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