xref: /openbmc/linux/drivers/i2c/i2c-core-base.c (revision 316be491)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux I2C core
4  *
5  * Copyright (C) 1995-99 Simon G. Vogl
6  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
9  *
10  * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11  */
12 
13 #define pr_fmt(fmt) "i2c-core: " fmt
14 
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/debugfs.h>
20 #include <linux/delay.h>
21 #include <linux/err.h>
22 #include <linux/errno.h>
23 #include <linux/gpio/consumer.h>
24 #include <linux/i2c.h>
25 #include <linux/i2c-smbus.h>
26 #include <linux/idr.h>
27 #include <linux/init.h>
28 #include <linux/interrupt.h>
29 #include <linux/irqflags.h>
30 #include <linux/jump_label.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/mutex.h>
34 #include <linux/of_device.h>
35 #include <linux/of.h>
36 #include <linux/of_irq.h>
37 #include <linux/pinctrl/consumer.h>
38 #include <linux/pinctrl/devinfo.h>
39 #include <linux/pm_domain.h>
40 #include <linux/pm_runtime.h>
41 #include <linux/pm_wakeirq.h>
42 #include <linux/property.h>
43 #include <linux/rwsem.h>
44 #include <linux/slab.h>
45 
46 #include "i2c-core.h"
47 
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/i2c.h>
50 
51 #define I2C_ADDR_OFFSET_TEN_BIT	0xa000
52 #define I2C_ADDR_OFFSET_SLAVE	0x1000
53 
54 #define I2C_ADDR_7BITS_MAX	0x77
55 #define I2C_ADDR_7BITS_COUNT	(I2C_ADDR_7BITS_MAX + 1)
56 
57 #define I2C_ADDR_DEVICE_ID	0x7c
58 
59 /*
60  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
61  * deletion of detected devices are serialized
62  */
63 static DEFINE_MUTEX(core_lock);
64 static DEFINE_IDR(i2c_adapter_idr);
65 
66 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67 
68 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
69 static bool is_registered;
70 
71 static struct dentry *i2c_debugfs_root;
72 
i2c_transfer_trace_reg(void)73 int i2c_transfer_trace_reg(void)
74 {
75 	static_branch_inc(&i2c_trace_msg_key);
76 	return 0;
77 }
78 
i2c_transfer_trace_unreg(void)79 void i2c_transfer_trace_unreg(void)
80 {
81 	static_branch_dec(&i2c_trace_msg_key);
82 }
83 
i2c_freq_mode_string(u32 bus_freq_hz)84 const char *i2c_freq_mode_string(u32 bus_freq_hz)
85 {
86 	switch (bus_freq_hz) {
87 	case I2C_MAX_STANDARD_MODE_FREQ:
88 		return "Standard Mode (100 kHz)";
89 	case I2C_MAX_FAST_MODE_FREQ:
90 		return "Fast Mode (400 kHz)";
91 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
92 		return "Fast Mode Plus (1.0 MHz)";
93 	case I2C_MAX_TURBO_MODE_FREQ:
94 		return "Turbo Mode (1.4 MHz)";
95 	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
96 		return "High Speed Mode (3.4 MHz)";
97 	case I2C_MAX_ULTRA_FAST_MODE_FREQ:
98 		return "Ultra Fast Mode (5.0 MHz)";
99 	default:
100 		return "Unknown Mode";
101 	}
102 }
103 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
104 
i2c_match_id(const struct i2c_device_id * id,const struct i2c_client * client)105 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
106 						const struct i2c_client *client)
107 {
108 	if (!(id && client))
109 		return NULL;
110 
111 	while (id->name[0]) {
112 		if (strcmp(client->name, id->name) == 0)
113 			return id;
114 		id++;
115 	}
116 	return NULL;
117 }
118 EXPORT_SYMBOL_GPL(i2c_match_id);
119 
i2c_get_match_data(const struct i2c_client * client)120 const void *i2c_get_match_data(const struct i2c_client *client)
121 {
122 	struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
123 	const struct i2c_device_id *match;
124 	const void *data;
125 
126 	data = device_get_match_data(&client->dev);
127 	if (!data) {
128 		match = i2c_match_id(driver->id_table, client);
129 		if (!match)
130 			return NULL;
131 
132 		data = (const void *)match->driver_data;
133 	}
134 
135 	return data;
136 }
137 EXPORT_SYMBOL(i2c_get_match_data);
138 
i2c_device_match(struct device * dev,struct device_driver * drv)139 static int i2c_device_match(struct device *dev, struct device_driver *drv)
140 {
141 	struct i2c_client	*client = i2c_verify_client(dev);
142 	struct i2c_driver	*driver;
143 
144 
145 	/* Attempt an OF style match */
146 	if (i2c_of_match_device(drv->of_match_table, client))
147 		return 1;
148 
149 	/* Then ACPI style match */
150 	if (acpi_driver_match_device(dev, drv))
151 		return 1;
152 
153 	driver = to_i2c_driver(drv);
154 
155 	/* Finally an I2C match */
156 	if (i2c_match_id(driver->id_table, client))
157 		return 1;
158 
159 	return 0;
160 }
161 
i2c_device_uevent(const struct device * dev,struct kobj_uevent_env * env)162 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
163 {
164 	const struct i2c_client *client = to_i2c_client(dev);
165 	int rc;
166 
167 	rc = of_device_uevent_modalias(dev, env);
168 	if (rc != -ENODEV)
169 		return rc;
170 
171 	rc = acpi_device_uevent_modalias(dev, env);
172 	if (rc != -ENODEV)
173 		return rc;
174 
175 	return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
176 }
177 
178 /* i2c bus recovery routines */
get_scl_gpio_value(struct i2c_adapter * adap)179 static int get_scl_gpio_value(struct i2c_adapter *adap)
180 {
181 	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
182 }
183 
set_scl_gpio_value(struct i2c_adapter * adap,int val)184 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
185 {
186 	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
187 }
188 
get_sda_gpio_value(struct i2c_adapter * adap)189 static int get_sda_gpio_value(struct i2c_adapter *adap)
190 {
191 	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
192 }
193 
set_sda_gpio_value(struct i2c_adapter * adap,int val)194 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
195 {
196 	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
197 }
198 
i2c_generic_bus_free(struct i2c_adapter * adap)199 static int i2c_generic_bus_free(struct i2c_adapter *adap)
200 {
201 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202 	int ret = -EOPNOTSUPP;
203 
204 	if (bri->get_bus_free)
205 		ret = bri->get_bus_free(adap);
206 	else if (bri->get_sda)
207 		ret = bri->get_sda(adap);
208 
209 	if (ret < 0)
210 		return ret;
211 
212 	return ret ? 0 : -EBUSY;
213 }
214 
215 /*
216  * We are generating clock pulses. ndelay() determines durating of clk pulses.
217  * We will generate clock with rate 100 KHz and so duration of both clock levels
218  * is: delay in ns = (10^6 / 100) / 2
219  */
220 #define RECOVERY_NDELAY		5000
221 #define RECOVERY_CLK_CNT	9
222 
i2c_generic_scl_recovery(struct i2c_adapter * adap)223 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
224 {
225 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
226 	int i = 0, scl = 1, ret = 0;
227 
228 	if (bri->prepare_recovery)
229 		bri->prepare_recovery(adap);
230 	if (bri->pinctrl)
231 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
232 
233 	/*
234 	 * If we can set SDA, we will always create a STOP to ensure additional
235 	 * pulses will do no harm. This is achieved by letting SDA follow SCL
236 	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
237 	 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
238 	 * here for simplicity.
239 	 */
240 	bri->set_scl(adap, scl);
241 	ndelay(RECOVERY_NDELAY);
242 	if (bri->set_sda)
243 		bri->set_sda(adap, scl);
244 	ndelay(RECOVERY_NDELAY / 2);
245 
246 	/*
247 	 * By this time SCL is high, as we need to give 9 falling-rising edges
248 	 */
249 	while (i++ < RECOVERY_CLK_CNT * 2) {
250 		if (scl) {
251 			/* SCL shouldn't be low here */
252 			if (!bri->get_scl(adap)) {
253 				dev_err(&adap->dev,
254 					"SCL is stuck low, exit recovery\n");
255 				ret = -EBUSY;
256 				break;
257 			}
258 		}
259 
260 		scl = !scl;
261 		bri->set_scl(adap, scl);
262 		/* Creating STOP again, see above */
263 		if (scl)  {
264 			/* Honour minimum tsu:sto */
265 			ndelay(RECOVERY_NDELAY);
266 		} else {
267 			/* Honour minimum tf and thd:dat */
268 			ndelay(RECOVERY_NDELAY / 2);
269 		}
270 		if (bri->set_sda)
271 			bri->set_sda(adap, scl);
272 		ndelay(RECOVERY_NDELAY / 2);
273 
274 		if (scl) {
275 			ret = i2c_generic_bus_free(adap);
276 			if (ret == 0)
277 				break;
278 		}
279 	}
280 
281 	/* If we can't check bus status, assume recovery worked */
282 	if (ret == -EOPNOTSUPP)
283 		ret = 0;
284 
285 	if (bri->unprepare_recovery)
286 		bri->unprepare_recovery(adap);
287 	if (bri->pinctrl)
288 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
289 
290 	return ret;
291 }
292 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
293 
i2c_recover_bus(struct i2c_adapter * adap)294 int i2c_recover_bus(struct i2c_adapter *adap)
295 {
296 	if (!adap->bus_recovery_info)
297 		return -EBUSY;
298 
299 	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
300 	return adap->bus_recovery_info->recover_bus(adap);
301 }
302 EXPORT_SYMBOL_GPL(i2c_recover_bus);
303 
i2c_gpio_init_pinctrl_recovery(struct i2c_adapter * adap)304 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
305 {
306 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
307 	struct device *dev = &adap->dev;
308 	struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
309 
310 	bri->pinctrl = p;
311 
312 	/*
313 	 * we can't change states without pinctrl, so remove the states if
314 	 * populated
315 	 */
316 	if (!p) {
317 		bri->pins_default = NULL;
318 		bri->pins_gpio = NULL;
319 		return;
320 	}
321 
322 	if (!bri->pins_default) {
323 		bri->pins_default = pinctrl_lookup_state(p,
324 							 PINCTRL_STATE_DEFAULT);
325 		if (IS_ERR(bri->pins_default)) {
326 			dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
327 			bri->pins_default = NULL;
328 		}
329 	}
330 	if (!bri->pins_gpio) {
331 		bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
332 		if (IS_ERR(bri->pins_gpio))
333 			bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
334 
335 		if (IS_ERR(bri->pins_gpio)) {
336 			dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
337 			bri->pins_gpio = NULL;
338 		}
339 	}
340 
341 	/* for pinctrl state changes, we need all the information */
342 	if (bri->pins_default && bri->pins_gpio) {
343 		dev_info(dev, "using pinctrl states for GPIO recovery");
344 	} else {
345 		bri->pinctrl = NULL;
346 		bri->pins_default = NULL;
347 		bri->pins_gpio = NULL;
348 	}
349 }
350 
i2c_gpio_init_generic_recovery(struct i2c_adapter * adap)351 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
352 {
353 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
354 	struct device *dev = &adap->dev;
355 	struct gpio_desc *gpiod;
356 	int ret = 0;
357 
358 	/*
359 	 * don't touch the recovery information if the driver is not using
360 	 * generic SCL recovery
361 	 */
362 	if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363 		return 0;
364 
365 	/*
366 	 * pins might be taken as GPIO, so we should inform pinctrl about
367 	 * this and move the state to GPIO
368 	 */
369 	if (bri->pinctrl)
370 		pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
371 
372 	/*
373 	 * if there is incomplete or no recovery information, see if generic
374 	 * GPIO recovery is available
375 	 */
376 	if (!bri->scl_gpiod) {
377 		gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
378 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 			ret  = -EPROBE_DEFER;
380 			goto cleanup_pinctrl_state;
381 		}
382 		if (!IS_ERR(gpiod)) {
383 			bri->scl_gpiod = gpiod;
384 			bri->recover_bus = i2c_generic_scl_recovery;
385 			dev_info(dev, "using generic GPIOs for recovery\n");
386 		}
387 	}
388 
389 	/* SDA GPIOD line is optional, so we care about DEFER only */
390 	if (!bri->sda_gpiod) {
391 		/*
392 		 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
393 		 * have no effect.
394 		 */
395 		gpiod_direction_output(bri->scl_gpiod, 0);
396 		udelay(10);
397 		gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
398 
399 		/* Wait a bit in case of a SDA glitch, and then release SCL. */
400 		udelay(10);
401 		gpiod_direction_output(bri->scl_gpiod, 1);
402 
403 		if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
404 			ret = -EPROBE_DEFER;
405 			goto cleanup_pinctrl_state;
406 		}
407 		if (!IS_ERR(gpiod))
408 			bri->sda_gpiod = gpiod;
409 	}
410 
411 cleanup_pinctrl_state:
412 	/* change the state of the pins back to their default state */
413 	if (bri->pinctrl)
414 		pinctrl_select_state(bri->pinctrl, bri->pins_default);
415 
416 	return ret;
417 }
418 
i2c_gpio_init_recovery(struct i2c_adapter * adap)419 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
420 {
421 	i2c_gpio_init_pinctrl_recovery(adap);
422 	return i2c_gpio_init_generic_recovery(adap);
423 }
424 
i2c_init_recovery(struct i2c_adapter * adap)425 static int i2c_init_recovery(struct i2c_adapter *adap)
426 {
427 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
428 	bool is_error_level = true;
429 	char *err_str;
430 
431 	if (!bri)
432 		return 0;
433 
434 	if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
435 		return -EPROBE_DEFER;
436 
437 	if (!bri->recover_bus) {
438 		err_str = "no suitable method provided";
439 		is_error_level = false;
440 		goto err;
441 	}
442 
443 	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
444 		bri->get_scl = get_scl_gpio_value;
445 		bri->set_scl = set_scl_gpio_value;
446 		if (bri->sda_gpiod) {
447 			bri->get_sda = get_sda_gpio_value;
448 			/* FIXME: add proper flag instead of '0' once available */
449 			if (gpiod_get_direction(bri->sda_gpiod) == 0)
450 				bri->set_sda = set_sda_gpio_value;
451 		}
452 	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
453 		/* Generic SCL recovery */
454 		if (!bri->set_scl || !bri->get_scl) {
455 			err_str = "no {get|set}_scl() found";
456 			goto err;
457 		}
458 		if (!bri->set_sda && !bri->get_sda) {
459 			err_str = "either get_sda() or set_sda() needed";
460 			goto err;
461 		}
462 	}
463 
464 	return 0;
465  err:
466 	if (is_error_level)
467 		dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
468 	else
469 		dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
470 	adap->bus_recovery_info = NULL;
471 
472 	return -EINVAL;
473 }
474 
i2c_smbus_host_notify_to_irq(const struct i2c_client * client)475 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
476 {
477 	struct i2c_adapter *adap = client->adapter;
478 	unsigned int irq;
479 
480 	if (!adap->host_notify_domain)
481 		return -ENXIO;
482 
483 	if (client->flags & I2C_CLIENT_TEN)
484 		return -EINVAL;
485 
486 	irq = irq_create_mapping(adap->host_notify_domain, client->addr);
487 
488 	return irq > 0 ? irq : -ENXIO;
489 }
490 
i2c_device_probe(struct device * dev)491 static int i2c_device_probe(struct device *dev)
492 {
493 	struct i2c_client	*client = i2c_verify_client(dev);
494 	struct i2c_driver	*driver;
495 	bool do_power_on;
496 	int status;
497 
498 	if (!client)
499 		return 0;
500 
501 	client->irq = client->init_irq;
502 
503 	if (!client->irq) {
504 		int irq = -ENOENT;
505 
506 		if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
507 			dev_dbg(dev, "Using Host Notify IRQ\n");
508 			/* Keep adapter active when Host Notify is required */
509 			pm_runtime_get_sync(&client->adapter->dev);
510 			irq = i2c_smbus_host_notify_to_irq(client);
511 		} else if (dev->of_node) {
512 			irq = of_irq_get_byname(dev->of_node, "irq");
513 			if (irq == -EINVAL || irq == -ENODATA)
514 				irq = of_irq_get(dev->of_node, 0);
515 		} else if (ACPI_COMPANION(dev)) {
516 			bool wake_capable;
517 
518 			irq = i2c_acpi_get_irq(client, &wake_capable);
519 			if (irq > 0 && wake_capable)
520 				client->flags |= I2C_CLIENT_WAKE;
521 		}
522 		if (irq == -EPROBE_DEFER) {
523 			status = irq;
524 			goto put_sync_adapter;
525 		}
526 
527 		if (irq < 0)
528 			irq = 0;
529 
530 		client->irq = irq;
531 	}
532 
533 	driver = to_i2c_driver(dev->driver);
534 
535 	/*
536 	 * An I2C ID table is not mandatory, if and only if, a suitable OF
537 	 * or ACPI ID table is supplied for the probing device.
538 	 */
539 	if (!driver->id_table &&
540 	    !acpi_driver_match_device(dev, dev->driver) &&
541 	    !i2c_of_match_device(dev->driver->of_match_table, client)) {
542 		status = -ENODEV;
543 		goto put_sync_adapter;
544 	}
545 
546 	if (client->flags & I2C_CLIENT_WAKE) {
547 		int wakeirq;
548 
549 		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
550 		if (wakeirq == -EPROBE_DEFER) {
551 			status = wakeirq;
552 			goto put_sync_adapter;
553 		}
554 
555 		device_init_wakeup(&client->dev, true);
556 
557 		if (wakeirq > 0 && wakeirq != client->irq)
558 			status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
559 		else if (client->irq > 0)
560 			status = dev_pm_set_wake_irq(dev, client->irq);
561 		else
562 			status = 0;
563 
564 		if (status)
565 			dev_warn(&client->dev, "failed to set up wakeup irq\n");
566 	}
567 
568 	dev_dbg(dev, "probe\n");
569 
570 	status = of_clk_set_defaults(dev->of_node, false);
571 	if (status < 0)
572 		goto err_clear_wakeup_irq;
573 
574 	do_power_on = !i2c_acpi_waive_d0_probe(dev);
575 	status = dev_pm_domain_attach(&client->dev, do_power_on);
576 	if (status)
577 		goto err_clear_wakeup_irq;
578 
579 	client->devres_group_id = devres_open_group(&client->dev, NULL,
580 						    GFP_KERNEL);
581 	if (!client->devres_group_id) {
582 		status = -ENOMEM;
583 		goto err_detach_pm_domain;
584 	}
585 
586 	if (driver->probe)
587 		status = driver->probe(client);
588 	else
589 		status = -EINVAL;
590 
591 	/*
592 	 * Note that we are not closing the devres group opened above so
593 	 * even resources that were attached to the device after probe is
594 	 * run are released when i2c_device_remove() is executed. This is
595 	 * needed as some drivers would allocate additional resources,
596 	 * for example when updating firmware.
597 	 */
598 
599 	if (status)
600 		goto err_release_driver_resources;
601 
602 	return 0;
603 
604 err_release_driver_resources:
605 	devres_release_group(&client->dev, client->devres_group_id);
606 err_detach_pm_domain:
607 	dev_pm_domain_detach(&client->dev, do_power_on);
608 err_clear_wakeup_irq:
609 	dev_pm_clear_wake_irq(&client->dev);
610 	device_init_wakeup(&client->dev, false);
611 put_sync_adapter:
612 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
613 		pm_runtime_put_sync(&client->adapter->dev);
614 
615 	return status;
616 }
617 
i2c_device_remove(struct device * dev)618 static void i2c_device_remove(struct device *dev)
619 {
620 	struct i2c_client	*client = to_i2c_client(dev);
621 	struct i2c_driver	*driver;
622 
623 	driver = to_i2c_driver(dev->driver);
624 	if (driver->remove) {
625 		dev_dbg(dev, "remove\n");
626 
627 		driver->remove(client);
628 	}
629 
630 	devres_release_group(&client->dev, client->devres_group_id);
631 
632 	dev_pm_domain_detach(&client->dev, true);
633 
634 	dev_pm_clear_wake_irq(&client->dev);
635 	device_init_wakeup(&client->dev, false);
636 
637 	client->irq = 0;
638 	if (client->flags & I2C_CLIENT_HOST_NOTIFY)
639 		pm_runtime_put(&client->adapter->dev);
640 }
641 
i2c_device_shutdown(struct device * dev)642 static void i2c_device_shutdown(struct device *dev)
643 {
644 	struct i2c_client *client = i2c_verify_client(dev);
645 	struct i2c_driver *driver;
646 
647 	if (!client || !dev->driver)
648 		return;
649 	driver = to_i2c_driver(dev->driver);
650 	if (driver->shutdown)
651 		driver->shutdown(client);
652 	else if (client->irq > 0)
653 		disable_irq(client->irq);
654 }
655 
i2c_client_dev_release(struct device * dev)656 static void i2c_client_dev_release(struct device *dev)
657 {
658 	kfree(to_i2c_client(dev));
659 }
660 
661 static ssize_t
name_show(struct device * dev,struct device_attribute * attr,char * buf)662 name_show(struct device *dev, struct device_attribute *attr, char *buf)
663 {
664 	return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
665 		       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
666 }
667 static DEVICE_ATTR_RO(name);
668 
669 static ssize_t
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)670 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
671 {
672 	struct i2c_client *client = to_i2c_client(dev);
673 	int len;
674 
675 	len = of_device_modalias(dev, buf, PAGE_SIZE);
676 	if (len != -ENODEV)
677 		return len;
678 
679 	len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
680 	if (len != -ENODEV)
681 		return len;
682 
683 	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
684 }
685 static DEVICE_ATTR_RO(modalias);
686 
687 static struct attribute *i2c_dev_attrs[] = {
688 	&dev_attr_name.attr,
689 	/* modalias helps coldplug:  modprobe $(cat .../modalias) */
690 	&dev_attr_modalias.attr,
691 	NULL
692 };
693 ATTRIBUTE_GROUPS(i2c_dev);
694 
695 struct bus_type i2c_bus_type = {
696 	.name		= "i2c",
697 	.match		= i2c_device_match,
698 	.probe		= i2c_device_probe,
699 	.remove		= i2c_device_remove,
700 	.shutdown	= i2c_device_shutdown,
701 };
702 EXPORT_SYMBOL_GPL(i2c_bus_type);
703 
704 struct device_type i2c_client_type = {
705 	.groups		= i2c_dev_groups,
706 	.uevent		= i2c_device_uevent,
707 	.release	= i2c_client_dev_release,
708 };
709 EXPORT_SYMBOL_GPL(i2c_client_type);
710 
711 
712 /**
713  * i2c_verify_client - return parameter as i2c_client, or NULL
714  * @dev: device, probably from some driver model iterator
715  *
716  * When traversing the driver model tree, perhaps using driver model
717  * iterators like @device_for_each_child(), you can't assume very much
718  * about the nodes you find.  Use this function to avoid oopses caused
719  * by wrongly treating some non-I2C device as an i2c_client.
720  */
i2c_verify_client(struct device * dev)721 struct i2c_client *i2c_verify_client(struct device *dev)
722 {
723 	return (dev->type == &i2c_client_type)
724 			? to_i2c_client(dev)
725 			: NULL;
726 }
727 EXPORT_SYMBOL(i2c_verify_client);
728 
729 
730 /* Return a unique address which takes the flags of the client into account */
i2c_encode_flags_to_addr(struct i2c_client * client)731 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
732 {
733 	unsigned short addr = client->addr;
734 
735 	/* For some client flags, add an arbitrary offset to avoid collisions */
736 	if (client->flags & I2C_CLIENT_TEN)
737 		addr |= I2C_ADDR_OFFSET_TEN_BIT;
738 
739 	if (client->flags & I2C_CLIENT_SLAVE)
740 		addr |= I2C_ADDR_OFFSET_SLAVE;
741 
742 	return addr;
743 }
744 
745 /* This is a permissive address validity check, I2C address map constraints
746  * are purposely not enforced, except for the general call address. */
i2c_check_addr_validity(unsigned int addr,unsigned short flags)747 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
748 {
749 	if (flags & I2C_CLIENT_TEN) {
750 		/* 10-bit address, all values are valid */
751 		if (addr > 0x3ff)
752 			return -EINVAL;
753 	} else {
754 		/* 7-bit address, reject the general call address */
755 		if (addr == 0x00 || addr > 0x7f)
756 			return -EINVAL;
757 	}
758 	return 0;
759 }
760 
761 /* And this is a strict address validity check, used when probing. If a
762  * device uses a reserved address, then it shouldn't be probed. 7-bit
763  * addressing is assumed, 10-bit address devices are rare and should be
764  * explicitly enumerated. */
i2c_check_7bit_addr_validity_strict(unsigned short addr)765 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
766 {
767 	/*
768 	 * Reserved addresses per I2C specification:
769 	 *  0x00       General call address / START byte
770 	 *  0x01       CBUS address
771 	 *  0x02       Reserved for different bus format
772 	 *  0x03       Reserved for future purposes
773 	 *  0x04-0x07  Hs-mode master code
774 	 *  0x78-0x7b  10-bit slave addressing
775 	 *  0x7c-0x7f  Reserved for future purposes
776 	 */
777 	if (addr < 0x08 || addr > 0x77)
778 		return -EINVAL;
779 	return 0;
780 }
781 
__i2c_check_addr_busy(struct device * dev,void * addrp)782 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
783 {
784 	struct i2c_client	*client = i2c_verify_client(dev);
785 	int			addr = *(int *)addrp;
786 
787 	if (client && i2c_encode_flags_to_addr(client) == addr)
788 		return -EBUSY;
789 	return 0;
790 }
791 
792 /* walk up mux tree */
i2c_check_mux_parents(struct i2c_adapter * adapter,int addr)793 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
794 {
795 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
796 	int result;
797 
798 	result = device_for_each_child(&adapter->dev, &addr,
799 					__i2c_check_addr_busy);
800 
801 	if (!result && parent)
802 		result = i2c_check_mux_parents(parent, addr);
803 
804 	return result;
805 }
806 
807 /* recurse down mux tree */
i2c_check_mux_children(struct device * dev,void * addrp)808 static int i2c_check_mux_children(struct device *dev, void *addrp)
809 {
810 	int result;
811 
812 	if (dev->type == &i2c_adapter_type)
813 		result = device_for_each_child(dev, addrp,
814 						i2c_check_mux_children);
815 	else
816 		result = __i2c_check_addr_busy(dev, addrp);
817 
818 	return result;
819 }
820 
i2c_check_addr_busy(struct i2c_adapter * adapter,int addr)821 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
822 {
823 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
824 	int result = 0;
825 
826 	if (parent)
827 		result = i2c_check_mux_parents(parent, addr);
828 
829 	if (!result)
830 		result = device_for_each_child(&adapter->dev, &addr,
831 						i2c_check_mux_children);
832 
833 	return result;
834 }
835 
836 /**
837  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
838  * @adapter: Target I2C bus segment
839  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
840  *	locks only this branch in the adapter tree
841  */
i2c_adapter_lock_bus(struct i2c_adapter * adapter,unsigned int flags)842 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
843 				 unsigned int flags)
844 {
845 	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
846 }
847 
848 /**
849  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
850  * @adapter: Target I2C bus segment
851  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
852  *	trylocks only this branch in the adapter tree
853  */
i2c_adapter_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)854 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
855 				   unsigned int flags)
856 {
857 	return rt_mutex_trylock(&adapter->bus_lock);
858 }
859 
860 /**
861  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
862  * @adapter: Target I2C bus segment
863  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
864  *	unlocks only this branch in the adapter tree
865  */
i2c_adapter_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)866 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
867 				   unsigned int flags)
868 {
869 	rt_mutex_unlock(&adapter->bus_lock);
870 }
871 
i2c_dev_set_name(struct i2c_adapter * adap,struct i2c_client * client,struct i2c_board_info const * info)872 static void i2c_dev_set_name(struct i2c_adapter *adap,
873 			     struct i2c_client *client,
874 			     struct i2c_board_info const *info)
875 {
876 	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
877 
878 	if (info && info->dev_name) {
879 		dev_set_name(&client->dev, "i2c-%s", info->dev_name);
880 		return;
881 	}
882 
883 	if (adev) {
884 		dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
885 		return;
886 	}
887 
888 	dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
889 		     i2c_encode_flags_to_addr(client));
890 }
891 
i2c_dev_irq_from_resources(const struct resource * resources,unsigned int num_resources)892 int i2c_dev_irq_from_resources(const struct resource *resources,
893 			       unsigned int num_resources)
894 {
895 	struct irq_data *irqd;
896 	int i;
897 
898 	for (i = 0; i < num_resources; i++) {
899 		const struct resource *r = &resources[i];
900 
901 		if (resource_type(r) != IORESOURCE_IRQ)
902 			continue;
903 
904 		if (r->flags & IORESOURCE_BITS) {
905 			irqd = irq_get_irq_data(r->start);
906 			if (!irqd)
907 				break;
908 
909 			irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
910 		}
911 
912 		return r->start;
913 	}
914 
915 	return 0;
916 }
917 
918 /*
919  * Serialize device instantiation in case it can be instantiated explicitly
920  * and by auto-detection
921  */
i2c_lock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)922 static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
923 			 unsigned short flags)
924 {
925 	if (!(flags & I2C_CLIENT_TEN) &&
926 	    test_and_set_bit(addr, adap->addrs_in_instantiation))
927 		return -EBUSY;
928 
929 	return 0;
930 }
931 
i2c_unlock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)932 static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
933 			    unsigned short flags)
934 {
935 	if (!(flags & I2C_CLIENT_TEN))
936 		clear_bit(addr, adap->addrs_in_instantiation);
937 }
938 
939 /**
940  * i2c_new_client_device - instantiate an i2c device
941  * @adap: the adapter managing the device
942  * @info: describes one I2C device; bus_num is ignored
943  * Context: can sleep
944  *
945  * Create an i2c device. Binding is handled through driver model
946  * probe()/remove() methods.  A driver may be bound to this device when we
947  * return from this function, or any later moment (e.g. maybe hotplugging will
948  * load the driver module).  This call is not appropriate for use by mainboard
949  * initialization logic, which usually runs during an arch_initcall() long
950  * before any i2c_adapter could exist.
951  *
952  * This returns the new i2c client, which may be saved for later use with
953  * i2c_unregister_device(); or an ERR_PTR to describe the error.
954  */
955 struct i2c_client *
i2c_new_client_device(struct i2c_adapter * adap,struct i2c_board_info const * info)956 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
957 {
958 	struct i2c_client *client;
959 	bool need_put = false;
960 	int status;
961 
962 	client = kzalloc(sizeof *client, GFP_KERNEL);
963 	if (!client)
964 		return ERR_PTR(-ENOMEM);
965 
966 	client->adapter = adap;
967 
968 	client->dev.platform_data = info->platform_data;
969 	client->flags = info->flags;
970 	client->addr = info->addr;
971 
972 	client->init_irq = info->irq;
973 	if (!client->init_irq)
974 		client->init_irq = i2c_dev_irq_from_resources(info->resources,
975 							 info->num_resources);
976 
977 	strscpy(client->name, info->type, sizeof(client->name));
978 
979 	status = i2c_check_addr_validity(client->addr, client->flags);
980 	if (status) {
981 		dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
982 			client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
983 		goto out_err_silent;
984 	}
985 
986 	status = i2c_lock_addr(adap, client->addr, client->flags);
987 	if (status)
988 		goto out_err_silent;
989 
990 	/* Check for address business */
991 	status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
992 	if (status)
993 		goto out_err;
994 
995 	client->dev.parent = &client->adapter->dev;
996 	client->dev.bus = &i2c_bus_type;
997 	client->dev.type = &i2c_client_type;
998 	client->dev.of_node = of_node_get(info->of_node);
999 	client->dev.fwnode = info->fwnode;
1000 
1001 	device_enable_async_suspend(&client->dev);
1002 
1003 	if (info->swnode) {
1004 		status = device_add_software_node(&client->dev, info->swnode);
1005 		if (status) {
1006 			dev_err(&adap->dev,
1007 				"Failed to add software node to client %s: %d\n",
1008 				client->name, status);
1009 			goto out_err_put_of_node;
1010 		}
1011 	}
1012 
1013 	i2c_dev_set_name(adap, client, info);
1014 	status = device_register(&client->dev);
1015 	if (status)
1016 		goto out_remove_swnode;
1017 
1018 	dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1019 		client->name, dev_name(&client->dev));
1020 
1021 	i2c_unlock_addr(adap, client->addr, client->flags);
1022 
1023 	return client;
1024 
1025 out_remove_swnode:
1026 	device_remove_software_node(&client->dev);
1027 	need_put = true;
1028 out_err_put_of_node:
1029 	of_node_put(info->of_node);
1030 out_err:
1031 	dev_err(&adap->dev,
1032 		"Failed to register i2c client %s at 0x%02x (%d)\n",
1033 		client->name, client->addr, status);
1034 	i2c_unlock_addr(adap, client->addr, client->flags);
1035 out_err_silent:
1036 	if (need_put)
1037 		put_device(&client->dev);
1038 	else
1039 		kfree(client);
1040 	return ERR_PTR(status);
1041 }
1042 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1043 
1044 /**
1045  * i2c_unregister_device - reverse effect of i2c_new_*_device()
1046  * @client: value returned from i2c_new_*_device()
1047  * Context: can sleep
1048  */
i2c_unregister_device(struct i2c_client * client)1049 void i2c_unregister_device(struct i2c_client *client)
1050 {
1051 	if (IS_ERR_OR_NULL(client))
1052 		return;
1053 
1054 	if (client->dev.of_node) {
1055 		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1056 		of_node_put(client->dev.of_node);
1057 	}
1058 
1059 	if (ACPI_COMPANION(&client->dev))
1060 		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1061 	device_remove_software_node(&client->dev);
1062 	device_unregister(&client->dev);
1063 }
1064 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1065 
1066 /**
1067  * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1068  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1069  *
1070  * Look up and return the &struct i2c_client corresponding to the @fwnode.
1071  * If no client can be found, or @fwnode is NULL, this returns NULL.
1072  *
1073  * The user must call put_device(&client->dev) once done with the i2c client.
1074  */
i2c_find_device_by_fwnode(struct fwnode_handle * fwnode)1075 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1076 {
1077 	struct i2c_client *client;
1078 	struct device *dev;
1079 
1080 	if (!fwnode)
1081 		return NULL;
1082 
1083 	dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1084 	if (!dev)
1085 		return NULL;
1086 
1087 	client = i2c_verify_client(dev);
1088 	if (!client)
1089 		put_device(dev);
1090 
1091 	return client;
1092 }
1093 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1094 
1095 
1096 static const struct i2c_device_id dummy_id[] = {
1097 	{ "dummy", 0 },
1098 	{ "smbus_host_notify", 0 },
1099 	{ },
1100 };
1101 
dummy_probe(struct i2c_client * client)1102 static int dummy_probe(struct i2c_client *client)
1103 {
1104 	return 0;
1105 }
1106 
1107 static struct i2c_driver dummy_driver = {
1108 	.driver.name	= "dummy",
1109 	.probe		= dummy_probe,
1110 	.id_table	= dummy_id,
1111 };
1112 
1113 /**
1114  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1115  * @adapter: the adapter managing the device
1116  * @address: seven bit address to be used
1117  * Context: can sleep
1118  *
1119  * This returns an I2C client bound to the "dummy" driver, intended for use
1120  * with devices that consume multiple addresses.  Examples of such chips
1121  * include various EEPROMS (like 24c04 and 24c08 models).
1122  *
1123  * These dummy devices have two main uses.  First, most I2C and SMBus calls
1124  * except i2c_transfer() need a client handle; the dummy will be that handle.
1125  * And second, this prevents the specified address from being bound to a
1126  * different driver.
1127  *
1128  * This returns the new i2c client, which should be saved for later use with
1129  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1130  */
i2c_new_dummy_device(struct i2c_adapter * adapter,u16 address)1131 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1132 {
1133 	struct i2c_board_info info = {
1134 		I2C_BOARD_INFO("dummy", address),
1135 	};
1136 
1137 	return i2c_new_client_device(adapter, &info);
1138 }
1139 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1140 
devm_i2c_release_dummy(void * client)1141 static void devm_i2c_release_dummy(void *client)
1142 {
1143 	i2c_unregister_device(client);
1144 }
1145 
1146 /**
1147  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1148  * @dev: device the managed resource is bound to
1149  * @adapter: the adapter managing the device
1150  * @address: seven bit address to be used
1151  * Context: can sleep
1152  *
1153  * This is the device-managed version of @i2c_new_dummy_device. It returns the
1154  * new i2c client or an ERR_PTR in case of an error.
1155  */
devm_i2c_new_dummy_device(struct device * dev,struct i2c_adapter * adapter,u16 address)1156 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1157 					     struct i2c_adapter *adapter,
1158 					     u16 address)
1159 {
1160 	struct i2c_client *client;
1161 	int ret;
1162 
1163 	client = i2c_new_dummy_device(adapter, address);
1164 	if (IS_ERR(client))
1165 		return client;
1166 
1167 	ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1168 	if (ret)
1169 		return ERR_PTR(ret);
1170 
1171 	return client;
1172 }
1173 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1174 
1175 /**
1176  * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1177  * and create the associated device
1178  * @client: Handle to the primary client
1179  * @name: Handle to specify which secondary address to get
1180  * @default_addr: Used as a fallback if no secondary address was specified
1181  * Context: can sleep
1182  *
1183  * I2C clients can be composed of multiple I2C slaves bound together in a single
1184  * component. The I2C client driver then binds to the master I2C slave and needs
1185  * to create I2C dummy clients to communicate with all the other slaves.
1186  *
1187  * This function creates and returns an I2C dummy client whose I2C address is
1188  * retrieved from the platform firmware based on the given slave name. If no
1189  * address is specified by the firmware default_addr is used.
1190  *
1191  * On DT-based platforms the address is retrieved from the "reg" property entry
1192  * cell whose "reg-names" value matches the slave name.
1193  *
1194  * This returns the new i2c client, which should be saved for later use with
1195  * i2c_unregister_device(); or an ERR_PTR to describe the error.
1196  */
i2c_new_ancillary_device(struct i2c_client * client,const char * name,u16 default_addr)1197 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1198 						const char *name,
1199 						u16 default_addr)
1200 {
1201 	struct device_node *np = client->dev.of_node;
1202 	u32 addr = default_addr;
1203 	int i;
1204 
1205 	if (np) {
1206 		i = of_property_match_string(np, "reg-names", name);
1207 		if (i >= 0)
1208 			of_property_read_u32_index(np, "reg", i, &addr);
1209 	}
1210 
1211 	dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1212 	return i2c_new_dummy_device(client->adapter, addr);
1213 }
1214 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1215 
1216 /* ------------------------------------------------------------------------- */
1217 
1218 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1219 
i2c_adapter_dev_release(struct device * dev)1220 static void i2c_adapter_dev_release(struct device *dev)
1221 {
1222 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1223 	complete(&adap->dev_released);
1224 }
1225 
i2c_adapter_depth(struct i2c_adapter * adapter)1226 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1227 {
1228 	unsigned int depth = 0;
1229 
1230 	while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1231 		depth++;
1232 
1233 	WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1234 		  "adapter depth exceeds lockdep subclass limit\n");
1235 
1236 	return depth;
1237 }
1238 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1239 
1240 /*
1241  * Let users instantiate I2C devices through sysfs. This can be used when
1242  * platform initialization code doesn't contain the proper data for
1243  * whatever reason. Also useful for drivers that do device detection and
1244  * detection fails, either because the device uses an unexpected address,
1245  * or this is a compatible device with different ID register values.
1246  *
1247  * Parameter checking may look overzealous, but we really don't want
1248  * the user to provide incorrect parameters.
1249  */
1250 static ssize_t
new_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1251 new_device_store(struct device *dev, struct device_attribute *attr,
1252 		 const char *buf, size_t count)
1253 {
1254 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1255 	struct i2c_board_info info;
1256 	struct i2c_client *client;
1257 	char *blank, end;
1258 	int res;
1259 
1260 	memset(&info, 0, sizeof(struct i2c_board_info));
1261 
1262 	blank = strchr(buf, ' ');
1263 	if (!blank) {
1264 		dev_err(dev, "%s: Missing parameters\n", "new_device");
1265 		return -EINVAL;
1266 	}
1267 	if (blank - buf > I2C_NAME_SIZE - 1) {
1268 		dev_err(dev, "%s: Invalid device name\n", "new_device");
1269 		return -EINVAL;
1270 	}
1271 	memcpy(info.type, buf, blank - buf);
1272 
1273 	/* Parse remaining parameters, reject extra parameters */
1274 	res = sscanf(++blank, "%hi%c", &info.addr, &end);
1275 	if (res < 1) {
1276 		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1277 		return -EINVAL;
1278 	}
1279 	if (res > 1  && end != '\n') {
1280 		dev_err(dev, "%s: Extra parameters\n", "new_device");
1281 		return -EINVAL;
1282 	}
1283 
1284 	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1285 		info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1286 		info.flags |= I2C_CLIENT_TEN;
1287 	}
1288 
1289 	if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1290 		info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1291 		info.flags |= I2C_CLIENT_SLAVE;
1292 	}
1293 
1294 	client = i2c_new_client_device(adap, &info);
1295 	if (IS_ERR(client))
1296 		return PTR_ERR(client);
1297 
1298 	/* Keep track of the added device */
1299 	mutex_lock(&adap->userspace_clients_lock);
1300 	list_add_tail(&client->detected, &adap->userspace_clients);
1301 	mutex_unlock(&adap->userspace_clients_lock);
1302 	dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1303 		 info.type, info.addr);
1304 
1305 	return count;
1306 }
1307 static DEVICE_ATTR_WO(new_device);
1308 
1309 /*
1310  * And of course let the users delete the devices they instantiated, if
1311  * they got it wrong. This interface can only be used to delete devices
1312  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1313  * don't delete devices to which some kernel code still has references.
1314  *
1315  * Parameter checking may look overzealous, but we really don't want
1316  * the user to delete the wrong device.
1317  */
1318 static ssize_t
delete_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1319 delete_device_store(struct device *dev, struct device_attribute *attr,
1320 		    const char *buf, size_t count)
1321 {
1322 	struct i2c_adapter *adap = to_i2c_adapter(dev);
1323 	struct i2c_client *client, *next;
1324 	unsigned short addr;
1325 	char end;
1326 	int res;
1327 
1328 	/* Parse parameters, reject extra parameters */
1329 	res = sscanf(buf, "%hi%c", &addr, &end);
1330 	if (res < 1) {
1331 		dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1332 		return -EINVAL;
1333 	}
1334 	if (res > 1  && end != '\n') {
1335 		dev_err(dev, "%s: Extra parameters\n", "delete_device");
1336 		return -EINVAL;
1337 	}
1338 
1339 	/* Make sure the device was added through sysfs */
1340 	res = -ENOENT;
1341 	mutex_lock_nested(&adap->userspace_clients_lock,
1342 			  i2c_adapter_depth(adap));
1343 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1344 				 detected) {
1345 		if (i2c_encode_flags_to_addr(client) == addr) {
1346 			dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1347 				 "delete_device", client->name, client->addr);
1348 
1349 			list_del(&client->detected);
1350 			i2c_unregister_device(client);
1351 			res = count;
1352 			break;
1353 		}
1354 	}
1355 	mutex_unlock(&adap->userspace_clients_lock);
1356 
1357 	if (res < 0)
1358 		dev_err(dev, "%s: Can't find device in list\n",
1359 			"delete_device");
1360 	return res;
1361 }
1362 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1363 				  delete_device_store);
1364 
1365 static struct attribute *i2c_adapter_attrs[] = {
1366 	&dev_attr_name.attr,
1367 	&dev_attr_new_device.attr,
1368 	&dev_attr_delete_device.attr,
1369 	NULL
1370 };
1371 ATTRIBUTE_GROUPS(i2c_adapter);
1372 
1373 struct device_type i2c_adapter_type = {
1374 	.groups		= i2c_adapter_groups,
1375 	.release	= i2c_adapter_dev_release,
1376 };
1377 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1378 
1379 /**
1380  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1381  * @dev: device, probably from some driver model iterator
1382  *
1383  * When traversing the driver model tree, perhaps using driver model
1384  * iterators like @device_for_each_child(), you can't assume very much
1385  * about the nodes you find.  Use this function to avoid oopses caused
1386  * by wrongly treating some non-I2C device as an i2c_adapter.
1387  */
i2c_verify_adapter(struct device * dev)1388 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1389 {
1390 	return (dev->type == &i2c_adapter_type)
1391 			? to_i2c_adapter(dev)
1392 			: NULL;
1393 }
1394 EXPORT_SYMBOL(i2c_verify_adapter);
1395 
1396 #ifdef CONFIG_I2C_COMPAT
1397 static struct class_compat *i2c_adapter_compat_class;
1398 #endif
1399 
i2c_scan_static_board_info(struct i2c_adapter * adapter)1400 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1401 {
1402 	struct i2c_devinfo	*devinfo;
1403 
1404 	down_read(&__i2c_board_lock);
1405 	list_for_each_entry(devinfo, &__i2c_board_list, list) {
1406 		if (devinfo->busnum == adapter->nr &&
1407 		    IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1408 			dev_err(&adapter->dev,
1409 				"Can't create device at 0x%02x\n",
1410 				devinfo->board_info.addr);
1411 	}
1412 	up_read(&__i2c_board_lock);
1413 }
1414 
i2c_do_add_adapter(struct i2c_driver * driver,struct i2c_adapter * adap)1415 static int i2c_do_add_adapter(struct i2c_driver *driver,
1416 			      struct i2c_adapter *adap)
1417 {
1418 	/* Detect supported devices on that bus, and instantiate them */
1419 	i2c_detect(adap, driver);
1420 
1421 	return 0;
1422 }
1423 
__process_new_adapter(struct device_driver * d,void * data)1424 static int __process_new_adapter(struct device_driver *d, void *data)
1425 {
1426 	return i2c_do_add_adapter(to_i2c_driver(d), data);
1427 }
1428 
1429 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1430 	.lock_bus =    i2c_adapter_lock_bus,
1431 	.trylock_bus = i2c_adapter_trylock_bus,
1432 	.unlock_bus =  i2c_adapter_unlock_bus,
1433 };
1434 
1435 /*
1436  * For a non-mux adapter, the lock_select operation locks the chain of
1437  * adapters upwards, returning the root. If there's a mux above this adapter
1438  * somehow, it should also get locked and the desired channel selected.
1439  */
i2c_adapter_lock_select(struct i2c_adapter * adapter)1440 static struct i2c_adapter *i2c_adapter_lock_select(struct i2c_adapter *adapter)
1441 {
1442 	struct i2c_adapter *ret = adapter;
1443 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1444 
1445 	if (parent) {
1446 		ret = parent->mux_root_ops->lock_select(parent);
1447 		if (IS_ERR(ret))
1448 			return ret;
1449 	}
1450 
1451 	adapter->lock_ops->lock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
1452 	return ret;
1453 }
1454 
i2c_adapter_unlock_deselect(struct i2c_adapter * adapter)1455 static void i2c_adapter_unlock_deselect(struct i2c_adapter *adapter)
1456 {
1457 	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
1458 
1459 	adapter->lock_ops->unlock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
1460 
1461 	if (parent)
1462 		parent->mux_root_ops->unlock_deselect(parent);
1463 }
1464 
1465 static const struct i2c_mux_root_operations i2c_adapter_mux_root_ops = {
1466 	.lock_select = i2c_adapter_lock_select,
1467 	.unlock_deselect = i2c_adapter_unlock_deselect,
1468 };
1469 
i2c_host_notify_irq_teardown(struct i2c_adapter * adap)1470 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1471 {
1472 	struct irq_domain *domain = adap->host_notify_domain;
1473 	irq_hw_number_t hwirq;
1474 
1475 	if (!domain)
1476 		return;
1477 
1478 	for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1479 		irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1480 
1481 	irq_domain_remove(domain);
1482 	adap->host_notify_domain = NULL;
1483 }
1484 
i2c_host_notify_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw_irq_num)1485 static int i2c_host_notify_irq_map(struct irq_domain *h,
1486 					  unsigned int virq,
1487 					  irq_hw_number_t hw_irq_num)
1488 {
1489 	irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1490 
1491 	return 0;
1492 }
1493 
1494 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1495 	.map = i2c_host_notify_irq_map,
1496 };
1497 
i2c_setup_host_notify_irq_domain(struct i2c_adapter * adap)1498 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1499 {
1500 	struct irq_domain *domain;
1501 
1502 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1503 		return 0;
1504 
1505 	domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1506 					  I2C_ADDR_7BITS_COUNT,
1507 					  &i2c_host_notify_irq_ops, adap);
1508 	if (!domain)
1509 		return -ENOMEM;
1510 
1511 	adap->host_notify_domain = domain;
1512 
1513 	return 0;
1514 }
1515 
1516 /**
1517  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1518  * I2C client.
1519  * @adap: the adapter
1520  * @addr: the I2C address of the notifying device
1521  * Context: can't sleep
1522  *
1523  * Helper function to be called from an I2C bus driver's interrupt
1524  * handler. It will schedule the Host Notify IRQ.
1525  */
i2c_handle_smbus_host_notify(struct i2c_adapter * adap,unsigned short addr)1526 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1527 {
1528 	int irq;
1529 
1530 	if (!adap)
1531 		return -EINVAL;
1532 
1533 	irq = irq_find_mapping(adap->host_notify_domain, addr);
1534 	if (irq <= 0)
1535 		return -ENXIO;
1536 
1537 	generic_handle_irq_safe(irq);
1538 
1539 	return 0;
1540 }
1541 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1542 
i2c_register_adapter(struct i2c_adapter * adap)1543 static int i2c_register_adapter(struct i2c_adapter *adap)
1544 {
1545 	int res = -EINVAL;
1546 
1547 	/* Can't register until after driver model init */
1548 	if (WARN_ON(!is_registered)) {
1549 		res = -EAGAIN;
1550 		goto out_list;
1551 	}
1552 
1553 	/* Sanity checks */
1554 	if (WARN(!adap->name[0], "i2c adapter has no name"))
1555 		goto out_list;
1556 
1557 	if (!adap->algo) {
1558 		pr_err("adapter '%s': no algo supplied!\n", adap->name);
1559 		goto out_list;
1560 	}
1561 
1562 	if (!adap->lock_ops)
1563 		adap->lock_ops = &i2c_adapter_lock_ops;
1564 
1565 	if (!adap->mux_root_ops)
1566 		adap->mux_root_ops = &i2c_adapter_mux_root_ops;
1567 
1568 	adap->locked_flags = 0;
1569 	rt_mutex_init(&adap->bus_lock);
1570 	rt_mutex_init(&adap->mux_lock);
1571 	mutex_init(&adap->userspace_clients_lock);
1572 	INIT_LIST_HEAD(&adap->userspace_clients);
1573 
1574 	/* Set default timeout to 1 second if not already set */
1575 	if (adap->timeout == 0)
1576 		adap->timeout = HZ;
1577 
1578 	/* register soft irqs for Host Notify */
1579 	res = i2c_setup_host_notify_irq_domain(adap);
1580 	if (res) {
1581 		pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1582 		       adap->name, res);
1583 		goto out_list;
1584 	}
1585 
1586 	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1587 	adap->dev.bus = &i2c_bus_type;
1588 	adap->dev.type = &i2c_adapter_type;
1589 	res = device_register(&adap->dev);
1590 	if (res) {
1591 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1592 		goto out_list;
1593 	}
1594 
1595 	adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
1596 
1597 	res = i2c_setup_smbus_alert(adap);
1598 	if (res)
1599 		goto out_reg;
1600 
1601 	device_enable_async_suspend(&adap->dev);
1602 	pm_runtime_no_callbacks(&adap->dev);
1603 	pm_suspend_ignore_children(&adap->dev, true);
1604 	pm_runtime_enable(&adap->dev);
1605 
1606 	res = i2c_init_recovery(adap);
1607 	if (res == -EPROBE_DEFER)
1608 		goto out_reg;
1609 
1610 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1611 
1612 #ifdef CONFIG_I2C_COMPAT
1613 	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1614 				       adap->dev.parent);
1615 	if (res)
1616 		dev_warn(&adap->dev,
1617 			 "Failed to create compatibility class link\n");
1618 #endif
1619 
1620 	/* create pre-declared device nodes */
1621 	of_i2c_register_devices(adap);
1622 	i2c_acpi_install_space_handler(adap);
1623 	i2c_acpi_register_devices(adap);
1624 
1625 	if (adap->nr < __i2c_first_dynamic_bus_num)
1626 		i2c_scan_static_board_info(adap);
1627 
1628 	/* Notify drivers */
1629 	mutex_lock(&core_lock);
1630 	bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1631 	mutex_unlock(&core_lock);
1632 
1633 	return 0;
1634 
1635 out_reg:
1636 	debugfs_remove_recursive(adap->debugfs);
1637 	init_completion(&adap->dev_released);
1638 	device_unregister(&adap->dev);
1639 	wait_for_completion(&adap->dev_released);
1640 out_list:
1641 	mutex_lock(&core_lock);
1642 	idr_remove(&i2c_adapter_idr, adap->nr);
1643 	mutex_unlock(&core_lock);
1644 	return res;
1645 }
1646 
1647 /**
1648  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1649  * @adap: the adapter to register (with adap->nr initialized)
1650  * Context: can sleep
1651  *
1652  * See i2c_add_numbered_adapter() for details.
1653  */
__i2c_add_numbered_adapter(struct i2c_adapter * adap)1654 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1655 {
1656 	int id;
1657 
1658 	mutex_lock(&core_lock);
1659 	id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1660 	mutex_unlock(&core_lock);
1661 	if (WARN(id < 0, "couldn't get idr"))
1662 		return id == -ENOSPC ? -EBUSY : id;
1663 
1664 	return i2c_register_adapter(adap);
1665 }
1666 
1667 /**
1668  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1669  * @adapter: the adapter to add
1670  * Context: can sleep
1671  *
1672  * This routine is used to declare an I2C adapter when its bus number
1673  * doesn't matter or when its bus number is specified by an dt alias.
1674  * Examples of bases when the bus number doesn't matter: I2C adapters
1675  * dynamically added by USB links or PCI plugin cards.
1676  *
1677  * When this returns zero, a new bus number was allocated and stored
1678  * in adap->nr, and the specified adapter became available for clients.
1679  * Otherwise, a negative errno value is returned.
1680  */
i2c_add_adapter(struct i2c_adapter * adapter)1681 int i2c_add_adapter(struct i2c_adapter *adapter)
1682 {
1683 	struct device *dev = &adapter->dev;
1684 	int id;
1685 
1686 	if (dev->of_node) {
1687 		id = of_alias_get_id(dev->of_node, "i2c");
1688 		if (id >= 0) {
1689 			adapter->nr = id;
1690 			return __i2c_add_numbered_adapter(adapter);
1691 		}
1692 	}
1693 
1694 	mutex_lock(&core_lock);
1695 	id = idr_alloc(&i2c_adapter_idr, adapter,
1696 		       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1697 	mutex_unlock(&core_lock);
1698 	if (WARN(id < 0, "couldn't get idr"))
1699 		return id;
1700 
1701 	adapter->nr = id;
1702 
1703 	return i2c_register_adapter(adapter);
1704 }
1705 EXPORT_SYMBOL(i2c_add_adapter);
1706 
1707 /**
1708  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1709  * @adap: the adapter to register (with adap->nr initialized)
1710  * Context: can sleep
1711  *
1712  * This routine is used to declare an I2C adapter when its bus number
1713  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1714  * or otherwise built in to the system's mainboard, and where i2c_board_info
1715  * is used to properly configure I2C devices.
1716  *
1717  * If the requested bus number is set to -1, then this function will behave
1718  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1719  *
1720  * If no devices have pre-been declared for this bus, then be sure to
1721  * register the adapter before any dynamically allocated ones.  Otherwise
1722  * the required bus ID may not be available.
1723  *
1724  * When this returns zero, the specified adapter became available for
1725  * clients using the bus number provided in adap->nr.  Also, the table
1726  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1727  * and the appropriate driver model device nodes are created.  Otherwise, a
1728  * negative errno value is returned.
1729  */
i2c_add_numbered_adapter(struct i2c_adapter * adap)1730 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1731 {
1732 	if (adap->nr == -1) /* -1 means dynamically assign bus id */
1733 		return i2c_add_adapter(adap);
1734 
1735 	return __i2c_add_numbered_adapter(adap);
1736 }
1737 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1738 
i2c_do_del_adapter(struct i2c_driver * driver,struct i2c_adapter * adapter)1739 static void i2c_do_del_adapter(struct i2c_driver *driver,
1740 			      struct i2c_adapter *adapter)
1741 {
1742 	struct i2c_client *client, *_n;
1743 
1744 	/* Remove the devices we created ourselves as the result of hardware
1745 	 * probing (using a driver's detect method) */
1746 	list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1747 		if (client->adapter == adapter) {
1748 			dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1749 				client->name, client->addr);
1750 			list_del(&client->detected);
1751 			i2c_unregister_device(client);
1752 		}
1753 	}
1754 }
1755 
__unregister_client(struct device * dev,void * dummy)1756 static int __unregister_client(struct device *dev, void *dummy)
1757 {
1758 	struct i2c_client *client = i2c_verify_client(dev);
1759 	if (client && strcmp(client->name, "dummy"))
1760 		i2c_unregister_device(client);
1761 	return 0;
1762 }
1763 
__unregister_dummy(struct device * dev,void * dummy)1764 static int __unregister_dummy(struct device *dev, void *dummy)
1765 {
1766 	struct i2c_client *client = i2c_verify_client(dev);
1767 	i2c_unregister_device(client);
1768 	return 0;
1769 }
1770 
__process_removed_adapter(struct device_driver * d,void * data)1771 static int __process_removed_adapter(struct device_driver *d, void *data)
1772 {
1773 	i2c_do_del_adapter(to_i2c_driver(d), data);
1774 	return 0;
1775 }
1776 
1777 /**
1778  * i2c_del_adapter - unregister I2C adapter
1779  * @adap: the adapter being unregistered
1780  * Context: can sleep
1781  *
1782  * This unregisters an I2C adapter which was previously registered
1783  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1784  */
i2c_del_adapter(struct i2c_adapter * adap)1785 void i2c_del_adapter(struct i2c_adapter *adap)
1786 {
1787 	struct i2c_adapter *found;
1788 	struct i2c_client *client, *next;
1789 
1790 	/* First make sure that this adapter was ever added */
1791 	mutex_lock(&core_lock);
1792 	found = idr_find(&i2c_adapter_idr, adap->nr);
1793 	mutex_unlock(&core_lock);
1794 	if (found != adap) {
1795 		pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1796 		return;
1797 	}
1798 
1799 	i2c_acpi_remove_space_handler(adap);
1800 	/* Tell drivers about this removal */
1801 	mutex_lock(&core_lock);
1802 	bus_for_each_drv(&i2c_bus_type, NULL, adap,
1803 			       __process_removed_adapter);
1804 	mutex_unlock(&core_lock);
1805 
1806 	/* Remove devices instantiated from sysfs */
1807 	mutex_lock_nested(&adap->userspace_clients_lock,
1808 			  i2c_adapter_depth(adap));
1809 	list_for_each_entry_safe(client, next, &adap->userspace_clients,
1810 				 detected) {
1811 		dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1812 			client->addr);
1813 		list_del(&client->detected);
1814 		i2c_unregister_device(client);
1815 	}
1816 	mutex_unlock(&adap->userspace_clients_lock);
1817 
1818 	/* Detach any active clients. This can't fail, thus we do not
1819 	 * check the returned value. This is a two-pass process, because
1820 	 * we can't remove the dummy devices during the first pass: they
1821 	 * could have been instantiated by real devices wishing to clean
1822 	 * them up properly, so we give them a chance to do that first. */
1823 	device_for_each_child(&adap->dev, NULL, __unregister_client);
1824 	device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1825 
1826 #ifdef CONFIG_I2C_COMPAT
1827 	class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1828 				 adap->dev.parent);
1829 #endif
1830 
1831 	/* device name is gone after device_unregister */
1832 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1833 
1834 	pm_runtime_disable(&adap->dev);
1835 
1836 	i2c_host_notify_irq_teardown(adap);
1837 
1838 	debugfs_remove_recursive(adap->debugfs);
1839 
1840 	/* wait until all references to the device are gone
1841 	 *
1842 	 * FIXME: This is old code and should ideally be replaced by an
1843 	 * alternative which results in decoupling the lifetime of the struct
1844 	 * device from the i2c_adapter, like spi or netdev do. Any solution
1845 	 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1846 	 */
1847 	init_completion(&adap->dev_released);
1848 	device_unregister(&adap->dev);
1849 	wait_for_completion(&adap->dev_released);
1850 
1851 	/* free bus id */
1852 	mutex_lock(&core_lock);
1853 	idr_remove(&i2c_adapter_idr, adap->nr);
1854 	mutex_unlock(&core_lock);
1855 
1856 	/* Clear the device structure in case this adapter is ever going to be
1857 	   added again */
1858 	memset(&adap->dev, 0, sizeof(adap->dev));
1859 }
1860 EXPORT_SYMBOL(i2c_del_adapter);
1861 
devm_i2c_del_adapter(void * adapter)1862 static void devm_i2c_del_adapter(void *adapter)
1863 {
1864 	i2c_del_adapter(adapter);
1865 }
1866 
1867 /**
1868  * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1869  * @dev: managing device for adding this I2C adapter
1870  * @adapter: the adapter to add
1871  * Context: can sleep
1872  *
1873  * Add adapter with dynamic bus number, same with i2c_add_adapter()
1874  * but the adapter will be auto deleted on driver detach.
1875  */
devm_i2c_add_adapter(struct device * dev,struct i2c_adapter * adapter)1876 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1877 {
1878 	int ret;
1879 
1880 	ret = i2c_add_adapter(adapter);
1881 	if (ret)
1882 		return ret;
1883 
1884 	return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1885 }
1886 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1887 
i2c_dev_or_parent_fwnode_match(struct device * dev,const void * data)1888 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1889 {
1890 	if (dev_fwnode(dev) == data)
1891 		return 1;
1892 
1893 	if (dev->parent && dev_fwnode(dev->parent) == data)
1894 		return 1;
1895 
1896 	return 0;
1897 }
1898 
1899 /**
1900  * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1901  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1902  *
1903  * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1904  * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1905  *
1906  * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1907  */
i2c_find_adapter_by_fwnode(struct fwnode_handle * fwnode)1908 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1909 {
1910 	struct i2c_adapter *adapter;
1911 	struct device *dev;
1912 
1913 	if (!fwnode)
1914 		return NULL;
1915 
1916 	dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1917 			      i2c_dev_or_parent_fwnode_match);
1918 	if (!dev)
1919 		return NULL;
1920 
1921 	adapter = i2c_verify_adapter(dev);
1922 	if (!adapter)
1923 		put_device(dev);
1924 
1925 	return adapter;
1926 }
1927 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1928 
1929 /**
1930  * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1931  * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1932  *
1933  * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1934  * and increment the adapter module's use count. If no adapter can be found,
1935  * or @fwnode is NULL, this returns NULL.
1936  *
1937  * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1938  * Note that this is different from i2c_find_adapter_by_node().
1939  */
i2c_get_adapter_by_fwnode(struct fwnode_handle * fwnode)1940 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1941 {
1942 	struct i2c_adapter *adapter;
1943 
1944 	adapter = i2c_find_adapter_by_fwnode(fwnode);
1945 	if (!adapter)
1946 		return NULL;
1947 
1948 	if (!try_module_get(adapter->owner)) {
1949 		put_device(&adapter->dev);
1950 		adapter = NULL;
1951 	}
1952 
1953 	return adapter;
1954 }
1955 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1956 
i2c_parse_timing(struct device * dev,char * prop_name,u32 * cur_val_p,u32 def_val,bool use_def)1957 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1958 			    u32 def_val, bool use_def)
1959 {
1960 	int ret;
1961 
1962 	ret = device_property_read_u32(dev, prop_name, cur_val_p);
1963 	if (ret && use_def)
1964 		*cur_val_p = def_val;
1965 
1966 	dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1967 }
1968 
1969 /**
1970  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1971  * @dev: The device to scan for I2C timing properties
1972  * @t: the i2c_timings struct to be filled with values
1973  * @use_defaults: bool to use sane defaults derived from the I2C specification
1974  *		  when properties are not found, otherwise don't update
1975  *
1976  * Scan the device for the generic I2C properties describing timing parameters
1977  * for the signal and fill the given struct with the results. If a property was
1978  * not found and use_defaults was true, then maximum timings are assumed which
1979  * are derived from the I2C specification. If use_defaults is not used, the
1980  * results will be as before, so drivers can apply their own defaults before
1981  * calling this helper. The latter is mainly intended for avoiding regressions
1982  * of existing drivers which want to switch to this function. New drivers
1983  * almost always should use the defaults.
1984  */
i2c_parse_fw_timings(struct device * dev,struct i2c_timings * t,bool use_defaults)1985 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1986 {
1987 	bool u = use_defaults;
1988 	u32 d;
1989 
1990 	i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1991 			 I2C_MAX_STANDARD_MODE_FREQ, u);
1992 
1993 	d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1994 	    t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1995 	i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1996 
1997 	d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1998 	i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1999 
2000 	i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
2001 			 &t->scl_int_delay_ns, 0, u);
2002 	i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
2003 			 t->scl_fall_ns, u);
2004 	i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
2005 	i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
2006 			 &t->digital_filter_width_ns, 0, u);
2007 	i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
2008 			 &t->analog_filter_cutoff_freq_hz, 0, u);
2009 }
2010 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
2011 
2012 /* ------------------------------------------------------------------------- */
2013 
i2c_for_each_dev(void * data,int (* fn)(struct device * dev,void * data))2014 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
2015 {
2016 	int res;
2017 
2018 	mutex_lock(&core_lock);
2019 	res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
2020 	mutex_unlock(&core_lock);
2021 
2022 	return res;
2023 }
2024 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
2025 
__process_new_driver(struct device * dev,void * data)2026 static int __process_new_driver(struct device *dev, void *data)
2027 {
2028 	if (dev->type != &i2c_adapter_type)
2029 		return 0;
2030 	return i2c_do_add_adapter(data, to_i2c_adapter(dev));
2031 }
2032 
2033 /*
2034  * An i2c_driver is used with one or more i2c_client (device) nodes to access
2035  * i2c slave chips, on a bus instance associated with some i2c_adapter.
2036  */
2037 
i2c_register_driver(struct module * owner,struct i2c_driver * driver)2038 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2039 {
2040 	int res;
2041 
2042 	/* Can't register until after driver model init */
2043 	if (WARN_ON(!is_registered))
2044 		return -EAGAIN;
2045 
2046 	/* add the driver to the list of i2c drivers in the driver core */
2047 	driver->driver.owner = owner;
2048 	driver->driver.bus = &i2c_bus_type;
2049 	INIT_LIST_HEAD(&driver->clients);
2050 
2051 	/* When registration returns, the driver core
2052 	 * will have called probe() for all matching-but-unbound devices.
2053 	 */
2054 	res = driver_register(&driver->driver);
2055 	if (res)
2056 		return res;
2057 
2058 	pr_debug("driver [%s] registered\n", driver->driver.name);
2059 
2060 	/* Walk the adapters that are already present */
2061 	i2c_for_each_dev(driver, __process_new_driver);
2062 
2063 	return 0;
2064 }
2065 EXPORT_SYMBOL(i2c_register_driver);
2066 
__process_removed_driver(struct device * dev,void * data)2067 static int __process_removed_driver(struct device *dev, void *data)
2068 {
2069 	if (dev->type == &i2c_adapter_type)
2070 		i2c_do_del_adapter(data, to_i2c_adapter(dev));
2071 	return 0;
2072 }
2073 
2074 /**
2075  * i2c_del_driver - unregister I2C driver
2076  * @driver: the driver being unregistered
2077  * Context: can sleep
2078  */
i2c_del_driver(struct i2c_driver * driver)2079 void i2c_del_driver(struct i2c_driver *driver)
2080 {
2081 	i2c_for_each_dev(driver, __process_removed_driver);
2082 
2083 	driver_unregister(&driver->driver);
2084 	pr_debug("driver [%s] unregistered\n", driver->driver.name);
2085 }
2086 EXPORT_SYMBOL(i2c_del_driver);
2087 
2088 /* ------------------------------------------------------------------------- */
2089 
2090 struct i2c_cmd_arg {
2091 	unsigned	cmd;
2092 	void		*arg;
2093 };
2094 
i2c_cmd(struct device * dev,void * _arg)2095 static int i2c_cmd(struct device *dev, void *_arg)
2096 {
2097 	struct i2c_client	*client = i2c_verify_client(dev);
2098 	struct i2c_cmd_arg	*arg = _arg;
2099 	struct i2c_driver	*driver;
2100 
2101 	if (!client || !client->dev.driver)
2102 		return 0;
2103 
2104 	driver = to_i2c_driver(client->dev.driver);
2105 	if (driver->command)
2106 		driver->command(client, arg->cmd, arg->arg);
2107 	return 0;
2108 }
2109 
i2c_clients_command(struct i2c_adapter * adap,unsigned int cmd,void * arg)2110 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2111 {
2112 	struct i2c_cmd_arg	cmd_arg;
2113 
2114 	cmd_arg.cmd = cmd;
2115 	cmd_arg.arg = arg;
2116 	device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2117 }
2118 EXPORT_SYMBOL(i2c_clients_command);
2119 
i2c_init(void)2120 static int __init i2c_init(void)
2121 {
2122 	int retval;
2123 
2124 	retval = of_alias_get_highest_id("i2c");
2125 
2126 	down_write(&__i2c_board_lock);
2127 	if (retval >= __i2c_first_dynamic_bus_num)
2128 		__i2c_first_dynamic_bus_num = retval + 1;
2129 	up_write(&__i2c_board_lock);
2130 
2131 	retval = bus_register(&i2c_bus_type);
2132 	if (retval)
2133 		return retval;
2134 
2135 	is_registered = true;
2136 
2137 	i2c_debugfs_root = debugfs_create_dir("i2c", NULL);
2138 
2139 #ifdef CONFIG_I2C_COMPAT
2140 	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2141 	if (!i2c_adapter_compat_class) {
2142 		retval = -ENOMEM;
2143 		goto bus_err;
2144 	}
2145 #endif
2146 	retval = i2c_add_driver(&dummy_driver);
2147 	if (retval)
2148 		goto class_err;
2149 
2150 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2151 		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2152 	if (IS_ENABLED(CONFIG_ACPI))
2153 		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2154 
2155 	return 0;
2156 
2157 class_err:
2158 #ifdef CONFIG_I2C_COMPAT
2159 	class_compat_unregister(i2c_adapter_compat_class);
2160 bus_err:
2161 #endif
2162 	is_registered = false;
2163 	bus_unregister(&i2c_bus_type);
2164 	return retval;
2165 }
2166 
i2c_exit(void)2167 static void __exit i2c_exit(void)
2168 {
2169 	if (IS_ENABLED(CONFIG_ACPI))
2170 		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2171 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2172 		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2173 	i2c_del_driver(&dummy_driver);
2174 #ifdef CONFIG_I2C_COMPAT
2175 	class_compat_unregister(i2c_adapter_compat_class);
2176 #endif
2177 	debugfs_remove_recursive(i2c_debugfs_root);
2178 	bus_unregister(&i2c_bus_type);
2179 	tracepoint_synchronize_unregister();
2180 }
2181 
2182 /* We must initialize early, because some subsystems register i2c drivers
2183  * in subsys_initcall() code, but are linked (and initialized) before i2c.
2184  */
2185 postcore_initcall(i2c_init);
2186 module_exit(i2c_exit);
2187 
2188 /* ----------------------------------------------------
2189  * the functional interface to the i2c busses.
2190  * ----------------------------------------------------
2191  */
2192 
2193 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2194 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2195 
i2c_quirk_error(struct i2c_adapter * adap,struct i2c_msg * msg,char * err_msg)2196 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2197 {
2198 	dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2199 			    err_msg, msg->addr, msg->len,
2200 			    msg->flags & I2C_M_RD ? "read" : "write");
2201 	return -EOPNOTSUPP;
2202 }
2203 
i2c_check_for_quirks(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2204 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2205 {
2206 	const struct i2c_adapter_quirks *q = adap->quirks;
2207 	int max_num = q->max_num_msgs, i;
2208 	bool do_len_check = true;
2209 
2210 	if (q->flags & I2C_AQ_COMB) {
2211 		max_num = 2;
2212 
2213 		/* special checks for combined messages */
2214 		if (num == 2) {
2215 			if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2216 				return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2217 
2218 			if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2219 				return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2220 
2221 			if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2222 				return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2223 
2224 			if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2225 				return i2c_quirk_error(adap, &msgs[0], "msg too long");
2226 
2227 			if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2228 				return i2c_quirk_error(adap, &msgs[1], "msg too long");
2229 
2230 			do_len_check = false;
2231 		}
2232 	}
2233 
2234 	if (i2c_quirk_exceeded(num, max_num))
2235 		return i2c_quirk_error(adap, &msgs[0], "too many messages");
2236 
2237 	for (i = 0; i < num; i++) {
2238 		u16 len = msgs[i].len;
2239 
2240 		if (msgs[i].flags & I2C_M_RD) {
2241 			if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2242 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2243 
2244 			if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2245 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2246 		} else {
2247 			if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2248 				return i2c_quirk_error(adap, &msgs[i], "msg too long");
2249 
2250 			if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2251 				return i2c_quirk_error(adap, &msgs[i], "no zero length");
2252 		}
2253 	}
2254 
2255 	return 0;
2256 }
2257 
2258 /**
2259  * __i2c_transfer - unlocked flavor of i2c_transfer
2260  * @adap: Handle to I2C bus
2261  * @msgs: One or more messages to execute before STOP is issued to
2262  *	terminate the operation; each message begins with a START.
2263  * @num: Number of messages to be executed.
2264  *
2265  * Returns negative errno, else the number of messages executed.
2266  *
2267  * Adapter lock must be held when calling this function. No debug logging
2268  * takes place.
2269  */
__i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2270 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2271 {
2272 	unsigned long orig_jiffies;
2273 	int ret, try;
2274 
2275 	if (!adap->algo->master_xfer) {
2276 		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2277 		return -EOPNOTSUPP;
2278 	}
2279 
2280 	if (WARN_ON(!msgs || num < 1))
2281 		return -EINVAL;
2282 
2283 	ret = __i2c_check_suspended(adap);
2284 	if (ret)
2285 		return ret;
2286 
2287 	if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2288 		return -EOPNOTSUPP;
2289 
2290 	/*
2291 	 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2292 	 * enabled.  This is an efficient way of keeping the for-loop from
2293 	 * being executed when not needed.
2294 	 */
2295 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2296 		int i;
2297 		for (i = 0; i < num; i++)
2298 			if (msgs[i].flags & I2C_M_RD)
2299 				trace_i2c_read(adap, &msgs[i], i);
2300 			else
2301 				trace_i2c_write(adap, &msgs[i], i);
2302 	}
2303 
2304 	/* Retry automatically on arbitration loss */
2305 	orig_jiffies = jiffies;
2306 	for (ret = 0, try = 0; try <= adap->retries; try++) {
2307 		if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2308 			ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2309 		else
2310 			ret = adap->algo->master_xfer(adap, msgs, num);
2311 
2312 		if (ret != -EAGAIN)
2313 			break;
2314 		if (time_after(jiffies, orig_jiffies + adap->timeout))
2315 			break;
2316 	}
2317 
2318 	if (static_branch_unlikely(&i2c_trace_msg_key)) {
2319 		int i;
2320 		for (i = 0; i < ret; i++)
2321 			if (msgs[i].flags & I2C_M_RD)
2322 				trace_i2c_reply(adap, &msgs[i], i);
2323 		trace_i2c_result(adap, num, ret);
2324 	}
2325 
2326 	return ret;
2327 }
2328 EXPORT_SYMBOL(__i2c_transfer);
2329 
2330 /**
2331  * i2c_transfer - execute a single or combined I2C message
2332  * @adap: Handle to I2C bus
2333  * @msgs: One or more messages to execute before STOP is issued to
2334  *	terminate the operation; each message begins with a START.
2335  * @num: Number of messages to be executed.
2336  *
2337  * Returns negative errno, else the number of messages executed.
2338  *
2339  * Note that there is no requirement that each message be sent to
2340  * the same slave address, although that is the most common model.
2341  */
i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2342 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2343 {
2344 	int ret;
2345 
2346 	/* REVISIT the fault reporting model here is weak:
2347 	 *
2348 	 *  - When we get an error after receiving N bytes from a slave,
2349 	 *    there is no way to report "N".
2350 	 *
2351 	 *  - When we get a NAK after transmitting N bytes to a slave,
2352 	 *    there is no way to report "N" ... or to let the master
2353 	 *    continue executing the rest of this combined message, if
2354 	 *    that's the appropriate response.
2355 	 *
2356 	 *  - When for example "num" is two and we successfully complete
2357 	 *    the first message but get an error part way through the
2358 	 *    second, it's unclear whether that should be reported as
2359 	 *    one (discarding status on the second message) or errno
2360 	 *    (discarding status on the first one).
2361 	 */
2362 	ret = __i2c_lock_bus_helper(adap);
2363 	if (ret)
2364 		return ret;
2365 
2366 	ret = __i2c_transfer(adap, msgs, num);
2367 	i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2368 
2369 	return ret;
2370 }
2371 EXPORT_SYMBOL(i2c_transfer);
2372 
2373 /**
2374  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2375  *			       to/from a buffer
2376  * @client: Handle to slave device
2377  * @buf: Where the data is stored
2378  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2379  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2380  *
2381  * Returns negative errno, or else the number of bytes transferred.
2382  */
i2c_transfer_buffer_flags(const struct i2c_client * client,char * buf,int count,u16 flags)2383 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2384 			      int count, u16 flags)
2385 {
2386 	int ret;
2387 	struct i2c_msg msg = {
2388 		.addr = client->addr,
2389 		.flags = flags | (client->flags & I2C_M_TEN),
2390 		.len = count,
2391 		.buf = buf,
2392 	};
2393 
2394 	ret = i2c_transfer(client->adapter, &msg, 1);
2395 
2396 	/*
2397 	 * If everything went ok (i.e. 1 msg transferred), return #bytes
2398 	 * transferred, else error code.
2399 	 */
2400 	return (ret == 1) ? count : ret;
2401 }
2402 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2403 
2404 /**
2405  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2406  * @client: The device to query
2407  * @id: The queried information
2408  *
2409  * Returns negative errno on error, zero on success.
2410  */
i2c_get_device_id(const struct i2c_client * client,struct i2c_device_identity * id)2411 int i2c_get_device_id(const struct i2c_client *client,
2412 		      struct i2c_device_identity *id)
2413 {
2414 	struct i2c_adapter *adap = client->adapter;
2415 	union i2c_smbus_data raw_id;
2416 	int ret;
2417 
2418 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2419 		return -EOPNOTSUPP;
2420 
2421 	raw_id.block[0] = 3;
2422 	ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2423 			     I2C_SMBUS_READ, client->addr << 1,
2424 			     I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2425 	if (ret)
2426 		return ret;
2427 
2428 	id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2429 	id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2430 	id->die_revision = raw_id.block[3] & 0x7;
2431 	return 0;
2432 }
2433 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2434 
2435 /**
2436  * i2c_client_get_device_id - get the driver match table entry of a device
2437  * @client: the device to query. The device must be bound to a driver
2438  *
2439  * Returns a pointer to the matching entry if found, NULL otherwise.
2440  */
i2c_client_get_device_id(const struct i2c_client * client)2441 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2442 {
2443 	const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2444 
2445 	return i2c_match_id(drv->id_table, client);
2446 }
2447 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2448 
2449 /* ----------------------------------------------------
2450  * the i2c address scanning function
2451  * Will not work for 10-bit addresses!
2452  * ----------------------------------------------------
2453  */
2454 
2455 /*
2456  * Legacy default probe function, mostly relevant for SMBus. The default
2457  * probe method is a quick write, but it is known to corrupt the 24RF08
2458  * EEPROMs due to a state machine bug, and could also irreversibly
2459  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2460  * we use a short byte read instead. Also, some bus drivers don't implement
2461  * quick write, so we fallback to a byte read in that case too.
2462  * On x86, there is another special case for FSC hardware monitoring chips,
2463  * which want regular byte reads (address 0x73.) Fortunately, these are the
2464  * only known chips using this I2C address on PC hardware.
2465  * Returns 1 if probe succeeded, 0 if not.
2466  */
i2c_default_probe(struct i2c_adapter * adap,unsigned short addr)2467 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2468 {
2469 	int err;
2470 	union i2c_smbus_data dummy;
2471 
2472 #ifdef CONFIG_X86
2473 	if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2474 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2475 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2476 				     I2C_SMBUS_BYTE_DATA, &dummy);
2477 	else
2478 #endif
2479 	if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2480 	 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2481 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2482 				     I2C_SMBUS_QUICK, NULL);
2483 	else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2484 		err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2485 				     I2C_SMBUS_BYTE, &dummy);
2486 	else {
2487 		dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2488 			 addr);
2489 		err = -EOPNOTSUPP;
2490 	}
2491 
2492 	return err >= 0;
2493 }
2494 
i2c_detect_address(struct i2c_client * temp_client,struct i2c_driver * driver)2495 static int i2c_detect_address(struct i2c_client *temp_client,
2496 			      struct i2c_driver *driver)
2497 {
2498 	struct i2c_board_info info;
2499 	struct i2c_adapter *adapter = temp_client->adapter;
2500 	int addr = temp_client->addr;
2501 	int err;
2502 
2503 	/* Make sure the address is valid */
2504 	err = i2c_check_7bit_addr_validity_strict(addr);
2505 	if (err) {
2506 		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2507 			 addr);
2508 		return err;
2509 	}
2510 
2511 	/* Skip if already in use (7 bit, no need to encode flags) */
2512 	if (i2c_check_addr_busy(adapter, addr))
2513 		return 0;
2514 
2515 	/* Make sure there is something at this address */
2516 	if (!i2c_default_probe(adapter, addr))
2517 		return 0;
2518 
2519 	/* Finally call the custom detection function */
2520 	memset(&info, 0, sizeof(struct i2c_board_info));
2521 	info.addr = addr;
2522 	err = driver->detect(temp_client, &info);
2523 	if (err) {
2524 		/* -ENODEV is returned if the detection fails. We catch it
2525 		   here as this isn't an error. */
2526 		return err == -ENODEV ? 0 : err;
2527 	}
2528 
2529 	/* Consistency check */
2530 	if (info.type[0] == '\0') {
2531 		dev_err(&adapter->dev,
2532 			"%s detection function provided no name for 0x%x\n",
2533 			driver->driver.name, addr);
2534 	} else {
2535 		struct i2c_client *client;
2536 
2537 		/* Detection succeeded, instantiate the device */
2538 		if (adapter->class & I2C_CLASS_DEPRECATED)
2539 			dev_warn(&adapter->dev,
2540 				"This adapter will soon drop class based instantiation of devices. "
2541 				"Please make sure client 0x%02x gets instantiated by other means. "
2542 				"Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2543 				info.addr);
2544 
2545 		dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2546 			info.type, info.addr);
2547 		client = i2c_new_client_device(adapter, &info);
2548 		if (!IS_ERR(client))
2549 			list_add_tail(&client->detected, &driver->clients);
2550 		else
2551 			dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2552 				info.type, info.addr);
2553 	}
2554 	return 0;
2555 }
2556 
i2c_detect(struct i2c_adapter * adapter,struct i2c_driver * driver)2557 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2558 {
2559 	const unsigned short *address_list;
2560 	struct i2c_client *temp_client;
2561 	int i, err = 0;
2562 
2563 	address_list = driver->address_list;
2564 	if (!driver->detect || !address_list)
2565 		return 0;
2566 
2567 	/* Warn that the adapter lost class based instantiation */
2568 	if (adapter->class == I2C_CLASS_DEPRECATED) {
2569 		dev_dbg(&adapter->dev,
2570 			"This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2571 			"If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2572 			driver->driver.name);
2573 		return 0;
2574 	}
2575 
2576 	/* Stop here if the classes do not match */
2577 	if (!(adapter->class & driver->class))
2578 		return 0;
2579 
2580 	/* Set up a temporary client to help detect callback */
2581 	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2582 	if (!temp_client)
2583 		return -ENOMEM;
2584 	temp_client->adapter = adapter;
2585 
2586 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2587 		dev_dbg(&adapter->dev,
2588 			"found normal entry for adapter %d, addr 0x%02x\n",
2589 			i2c_adapter_id(adapter), address_list[i]);
2590 		temp_client->addr = address_list[i];
2591 		err = i2c_detect_address(temp_client, driver);
2592 		if (unlikely(err))
2593 			break;
2594 	}
2595 
2596 	kfree(temp_client);
2597 	return err;
2598 }
2599 
i2c_probe_func_quick_read(struct i2c_adapter * adap,unsigned short addr)2600 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2601 {
2602 	return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2603 			      I2C_SMBUS_QUICK, NULL) >= 0;
2604 }
2605 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2606 
2607 struct i2c_client *
i2c_new_scanned_device(struct i2c_adapter * adap,struct i2c_board_info * info,unsigned short const * addr_list,int (* probe)(struct i2c_adapter * adap,unsigned short addr))2608 i2c_new_scanned_device(struct i2c_adapter *adap,
2609 		       struct i2c_board_info *info,
2610 		       unsigned short const *addr_list,
2611 		       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2612 {
2613 	int i;
2614 
2615 	if (!probe)
2616 		probe = i2c_default_probe;
2617 
2618 	for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2619 		/* Check address validity */
2620 		if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2621 			dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2622 				 addr_list[i]);
2623 			continue;
2624 		}
2625 
2626 		/* Check address availability (7 bit, no need to encode flags) */
2627 		if (i2c_check_addr_busy(adap, addr_list[i])) {
2628 			dev_dbg(&adap->dev,
2629 				"Address 0x%02x already in use, not probing\n",
2630 				addr_list[i]);
2631 			continue;
2632 		}
2633 
2634 		/* Test address responsiveness */
2635 		if (probe(adap, addr_list[i]))
2636 			break;
2637 	}
2638 
2639 	if (addr_list[i] == I2C_CLIENT_END) {
2640 		dev_dbg(&adap->dev, "Probing failed, no device found\n");
2641 		return ERR_PTR(-ENODEV);
2642 	}
2643 
2644 	info->addr = addr_list[i];
2645 	return i2c_new_client_device(adap, info);
2646 }
2647 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2648 
i2c_get_adapter(int nr)2649 struct i2c_adapter *i2c_get_adapter(int nr)
2650 {
2651 	struct i2c_adapter *adapter;
2652 
2653 	mutex_lock(&core_lock);
2654 	adapter = idr_find(&i2c_adapter_idr, nr);
2655 	if (!adapter)
2656 		goto exit;
2657 
2658 	if (try_module_get(adapter->owner))
2659 		get_device(&adapter->dev);
2660 	else
2661 		adapter = NULL;
2662 
2663  exit:
2664 	mutex_unlock(&core_lock);
2665 	return adapter;
2666 }
2667 EXPORT_SYMBOL(i2c_get_adapter);
2668 
i2c_put_adapter(struct i2c_adapter * adap)2669 void i2c_put_adapter(struct i2c_adapter *adap)
2670 {
2671 	if (!adap)
2672 		return;
2673 
2674 	module_put(adap->owner);
2675 	/* Should be last, otherwise we risk use-after-free with 'adap' */
2676 	put_device(&adap->dev);
2677 }
2678 EXPORT_SYMBOL(i2c_put_adapter);
2679 
2680 /**
2681  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2682  * @msg: the message to be checked
2683  * @threshold: the minimum number of bytes for which using DMA makes sense.
2684  *	       Should at least be 1.
2685  *
2686  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2687  *	   Or a valid pointer to be used with DMA. After use, release it by
2688  *	   calling i2c_put_dma_safe_msg_buf().
2689  *
2690  * This function must only be called from process context!
2691  */
i2c_get_dma_safe_msg_buf(struct i2c_msg * msg,unsigned int threshold)2692 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2693 {
2694 	/* also skip 0-length msgs for bogus thresholds of 0 */
2695 	if (!threshold)
2696 		pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2697 			 msg->addr);
2698 	if (msg->len < threshold || msg->len == 0)
2699 		return NULL;
2700 
2701 	if (msg->flags & I2C_M_DMA_SAFE)
2702 		return msg->buf;
2703 
2704 	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2705 		 msg->addr, msg->len);
2706 
2707 	if (msg->flags & I2C_M_RD)
2708 		return kzalloc(msg->len, GFP_KERNEL);
2709 	else
2710 		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2711 }
2712 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2713 
2714 /**
2715  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2716  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2717  * @msg: the message which the buffer corresponds to
2718  * @xferred: bool saying if the message was transferred
2719  */
i2c_put_dma_safe_msg_buf(u8 * buf,struct i2c_msg * msg,bool xferred)2720 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2721 {
2722 	if (!buf || buf == msg->buf)
2723 		return;
2724 
2725 	if (xferred && msg->flags & I2C_M_RD)
2726 		memcpy(msg->buf, buf, msg->len);
2727 
2728 	kfree(buf);
2729 }
2730 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2731 
2732 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2733 MODULE_DESCRIPTION("I2C-Bus main module");
2734 MODULE_LICENSE("GPL");
2735