1 /*
2  * I2C multiplexer
3  *
4  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
5  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
6  *
7  * This module supports the PCA954x and PCA954x series of I2C multiplexer/switch
8  * chips made by NXP Semiconductors.
9  * This includes the:
10  *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
11  *	 PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
12  *
13  * These chips are all controlled via the I2C bus itself, and all have a
14  * single 8-bit register. The upstream "parent" bus fans out to two,
15  * four, or eight downstream busses or channels; which of these
16  * are selected is determined by the chip type and register contents. A
17  * mux can select only one sub-bus at a time; a switch can select any
18  * combination simultaneously.
19  *
20  * Based on:
21  *	pca954x.c from Kumar Gala <galak@kernel.crashing.org>
22  * Copyright (C) 2006
23  *
24  * Based on:
25  *	pca954x.c from Ken Harrenstien
26  * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
27  *
28  * Based on:
29  *	i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
30  * and
31  *	pca9540.c from Jean Delvare <jdelvare@suse.de>.
32  *
33  * This file is licensed under the terms of the GNU General Public
34  * License version 2. This program is licensed "as is" without any
35  * warranty of any kind, whether express or implied.
36  */
37 
38 #include <linux/device.h>
39 #include <linux/delay.h>
40 #include <linux/gpio/consumer.h>
41 #include <linux/i2c.h>
42 #include <linux/i2c-mux.h>
43 #include <linux/interrupt.h>
44 #include <linux/irq.h>
45 #include <linux/module.h>
46 #include <linux/of.h>
47 #include <linux/of_device.h>
48 #include <linux/of_irq.h>
49 #include <linux/platform_data/pca954x.h>
50 #include <linux/pm.h>
51 #include <linux/slab.h>
52 #include <linux/spinlock.h>
53 
54 #define PCA954X_MAX_NCHANS 8
55 
56 #define PCA954X_IRQ_OFFSET 4
57 
58 enum pca_type {
59 	pca_9540,
60 	pca_9542,
61 	pca_9543,
62 	pca_9544,
63 	pca_9545,
64 	pca_9546,
65 	pca_9547,
66 	pca_9548,
67 	pca_9846,
68 	pca_9847,
69 	pca_9848,
70 	pca_9849,
71 };
72 
73 struct chip_desc {
74 	u8 nchans;
75 	u8 enable;	/* used for muxes only */
76 	u8 has_irq;
77 	enum muxtype {
78 		pca954x_ismux = 0,
79 		pca954x_isswi
80 	} muxtype;
81 	struct i2c_device_identity id;
82 };
83 
84 struct pca954x {
85 	const struct chip_desc *chip;
86 
87 	u8 last_chan;		/* last register value */
88 	u8 deselect;
89 	struct i2c_client *client;
90 
91 	struct irq_domain *irq;
92 	unsigned int irq_mask;
93 	raw_spinlock_t lock;
94 };
95 
96 /* Provide specs for the PCA954x types we know about */
97 static const struct chip_desc chips[] = {
98 	[pca_9540] = {
99 		.nchans = 2,
100 		.enable = 0x4,
101 		.muxtype = pca954x_ismux,
102 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
103 	},
104 	[pca_9542] = {
105 		.nchans = 2,
106 		.enable = 0x4,
107 		.has_irq = 1,
108 		.muxtype = pca954x_ismux,
109 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
110 	},
111 	[pca_9543] = {
112 		.nchans = 2,
113 		.has_irq = 1,
114 		.muxtype = pca954x_isswi,
115 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
116 	},
117 	[pca_9544] = {
118 		.nchans = 4,
119 		.enable = 0x4,
120 		.has_irq = 1,
121 		.muxtype = pca954x_ismux,
122 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
123 	},
124 	[pca_9545] = {
125 		.nchans = 4,
126 		.has_irq = 1,
127 		.muxtype = pca954x_isswi,
128 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
129 	},
130 	[pca_9546] = {
131 		.nchans = 4,
132 		.muxtype = pca954x_isswi,
133 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
134 	},
135 	[pca_9547] = {
136 		.nchans = 8,
137 		.enable = 0x8,
138 		.muxtype = pca954x_ismux,
139 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
140 	},
141 	[pca_9548] = {
142 		.nchans = 8,
143 		.muxtype = pca954x_isswi,
144 		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
145 	},
146 	[pca_9846] = {
147 		.nchans = 4,
148 		.muxtype = pca954x_isswi,
149 		.id = {
150 			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
151 			.part_id = 0x10b,
152 		},
153 	},
154 	[pca_9847] = {
155 		.nchans = 8,
156 		.enable = 0x8,
157 		.muxtype = pca954x_ismux,
158 		.id = {
159 			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
160 			.part_id = 0x108,
161 		},
162 	},
163 	[pca_9848] = {
164 		.nchans = 8,
165 		.muxtype = pca954x_isswi,
166 		.id = {
167 			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
168 			.part_id = 0x10a,
169 		},
170 	},
171 	[pca_9849] = {
172 		.nchans = 4,
173 		.enable = 0x4,
174 		.muxtype = pca954x_ismux,
175 		.id = {
176 			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
177 			.part_id = 0x109,
178 		},
179 	},
180 };
181 
182 static const struct i2c_device_id pca954x_id[] = {
183 	{ "pca9540", pca_9540 },
184 	{ "pca9542", pca_9542 },
185 	{ "pca9543", pca_9543 },
186 	{ "pca9544", pca_9544 },
187 	{ "pca9545", pca_9545 },
188 	{ "pca9546", pca_9546 },
189 	{ "pca9547", pca_9547 },
190 	{ "pca9548", pca_9548 },
191 	{ "pca9846", pca_9846 },
192 	{ "pca9847", pca_9847 },
193 	{ "pca9848", pca_9848 },
194 	{ "pca9849", pca_9849 },
195 	{ }
196 };
197 MODULE_DEVICE_TABLE(i2c, pca954x_id);
198 
199 #ifdef CONFIG_OF
200 static const struct of_device_id pca954x_of_match[] = {
201 	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
202 	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
203 	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
204 	{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
205 	{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
206 	{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
207 	{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
208 	{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
209 	{ .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
210 	{ .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
211 	{ .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
212 	{ .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
213 	{}
214 };
215 MODULE_DEVICE_TABLE(of, pca954x_of_match);
216 #endif
217 
218 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
219    for this as they will try to lock adapter a second time */
220 static int pca954x_reg_write(struct i2c_adapter *adap,
221 			     struct i2c_client *client, u8 val)
222 {
223 	int ret = -ENODEV;
224 
225 	if (adap->algo->master_xfer) {
226 		struct i2c_msg msg;
227 		char buf[1];
228 
229 		msg.addr = client->addr;
230 		msg.flags = 0;
231 		msg.len = 1;
232 		buf[0] = val;
233 		msg.buf = buf;
234 		ret = __i2c_transfer(adap, &msg, 1);
235 
236 		if (ret >= 0 && ret != 1)
237 			ret = -EREMOTEIO;
238 	} else {
239 		union i2c_smbus_data data;
240 		ret = adap->algo->smbus_xfer(adap, client->addr,
241 					     client->flags,
242 					     I2C_SMBUS_WRITE,
243 					     val, I2C_SMBUS_BYTE, &data);
244 	}
245 
246 	return ret;
247 }
248 
249 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
250 {
251 	struct pca954x *data = i2c_mux_priv(muxc);
252 	struct i2c_client *client = data->client;
253 	const struct chip_desc *chip = data->chip;
254 	u8 regval;
255 	int ret = 0;
256 
257 	/* we make switches look like muxes, not sure how to be smarter */
258 	if (chip->muxtype == pca954x_ismux)
259 		regval = chan | chip->enable;
260 	else
261 		regval = 1 << chan;
262 
263 	/* Only select the channel if its different from the last channel */
264 	if (data->last_chan != regval) {
265 		ret = pca954x_reg_write(muxc->parent, client, regval);
266 		data->last_chan = ret < 0 ? 0 : regval;
267 	}
268 
269 	return ret;
270 }
271 
272 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
273 {
274 	struct pca954x *data = i2c_mux_priv(muxc);
275 	struct i2c_client *client = data->client;
276 
277 	if (!(data->deselect & (1 << chan)))
278 		return 0;
279 
280 	/* Deselect active channel */
281 	data->last_chan = 0;
282 	return pca954x_reg_write(muxc->parent, client, data->last_chan);
283 }
284 
285 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
286 {
287 	struct pca954x *data = dev_id;
288 	unsigned int child_irq;
289 	int ret, i, handled = 0;
290 
291 	ret = i2c_smbus_read_byte(data->client);
292 	if (ret < 0)
293 		return IRQ_NONE;
294 
295 	for (i = 0; i < data->chip->nchans; i++) {
296 		if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
297 			child_irq = irq_linear_revmap(data->irq, i);
298 			handle_nested_irq(child_irq);
299 			handled++;
300 		}
301 	}
302 	return handled ? IRQ_HANDLED : IRQ_NONE;
303 }
304 
305 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
306 {
307 	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
308 		return -EINVAL;
309 	return 0;
310 }
311 
312 static struct irq_chip pca954x_irq_chip = {
313 	.name = "i2c-mux-pca954x",
314 	.irq_set_type = pca954x_irq_set_type,
315 };
316 
317 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
318 {
319 	struct pca954x *data = i2c_mux_priv(muxc);
320 	struct i2c_client *client = data->client;
321 	int c, irq;
322 
323 	if (!data->chip->has_irq || client->irq <= 0)
324 		return 0;
325 
326 	raw_spin_lock_init(&data->lock);
327 
328 	data->irq = irq_domain_add_linear(client->dev.of_node,
329 					  data->chip->nchans,
330 					  &irq_domain_simple_ops, data);
331 	if (!data->irq)
332 		return -ENODEV;
333 
334 	for (c = 0; c < data->chip->nchans; c++) {
335 		irq = irq_create_mapping(data->irq, c);
336 		if (!irq) {
337 			dev_err(&client->dev, "failed irq create map\n");
338 			return -EINVAL;
339 		}
340 		irq_set_chip_data(irq, data);
341 		irq_set_chip_and_handler(irq, &pca954x_irq_chip,
342 			handle_simple_irq);
343 	}
344 
345 	return 0;
346 }
347 
348 static void pca954x_cleanup(struct i2c_mux_core *muxc)
349 {
350 	struct pca954x *data = i2c_mux_priv(muxc);
351 	int c, irq;
352 
353 	if (data->irq) {
354 		for (c = 0; c < data->chip->nchans; c++) {
355 			irq = irq_find_mapping(data->irq, c);
356 			irq_dispose_mapping(irq);
357 		}
358 		irq_domain_remove(data->irq);
359 	}
360 	i2c_mux_del_adapters(muxc);
361 }
362 
363 /*
364  * I2C init/probing/exit functions
365  */
366 static int pca954x_probe(struct i2c_client *client,
367 			 const struct i2c_device_id *id)
368 {
369 	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
370 	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
371 	struct device_node *of_node = client->dev.of_node;
372 	bool idle_disconnect_dt;
373 	struct gpio_desc *gpio;
374 	int num, force, class;
375 	struct i2c_mux_core *muxc;
376 	struct pca954x *data;
377 	int ret;
378 
379 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
380 		return -ENODEV;
381 
382 	muxc = i2c_mux_alloc(adap, &client->dev,
383 			     PCA954X_MAX_NCHANS, sizeof(*data), 0,
384 			     pca954x_select_chan, pca954x_deselect_mux);
385 	if (!muxc)
386 		return -ENOMEM;
387 	data = i2c_mux_priv(muxc);
388 
389 	i2c_set_clientdata(client, muxc);
390 	data->client = client;
391 
392 	/* Reset the mux if a reset GPIO is specified. */
393 	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
394 	if (IS_ERR(gpio))
395 		return PTR_ERR(gpio);
396 	if (gpio) {
397 		udelay(1);
398 		gpiod_set_value_cansleep(gpio, 0);
399 		/* Give the chip some time to recover. */
400 		udelay(1);
401 	}
402 
403 	data->chip = of_device_get_match_data(&client->dev);
404 	if (!data->chip)
405 		data->chip = &chips[id->driver_data];
406 
407 	if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
408 		struct i2c_device_identity id;
409 
410 		ret = i2c_get_device_id(client, &id);
411 		if (ret && ret != -EOPNOTSUPP)
412 			return ret;
413 
414 		if (!ret &&
415 		    (id.manufacturer_id != data->chip->id.manufacturer_id ||
416 		     id.part_id != data->chip->id.part_id)) {
417 			dev_warn(&client->dev,
418 				 "unexpected device id %03x-%03x-%x\n",
419 				 id.manufacturer_id, id.part_id,
420 				 id.die_revision);
421 			return -ENODEV;
422 		}
423 	}
424 
425 	/* Write the mux register at addr to verify
426 	 * that the mux is in fact present. This also
427 	 * initializes the mux to disconnected state.
428 	 */
429 	if (i2c_smbus_write_byte(client, 0) < 0) {
430 		dev_warn(&client->dev, "probe failed\n");
431 		return -ENODEV;
432 	}
433 
434 	data->last_chan = 0;		   /* force the first selection */
435 
436 	idle_disconnect_dt = of_node &&
437 		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
438 
439 	ret = pca954x_irq_setup(muxc);
440 	if (ret)
441 		goto fail_cleanup;
442 
443 	/* Now create an adapter for each channel */
444 	for (num = 0; num < data->chip->nchans; num++) {
445 		bool idle_disconnect_pd = false;
446 
447 		force = 0;			  /* dynamic adap number */
448 		class = 0;			  /* no class by default */
449 		if (pdata) {
450 			if (num < pdata->num_modes) {
451 				/* force static number */
452 				force = pdata->modes[num].adap_id;
453 				class = pdata->modes[num].class;
454 			} else
455 				/* discard unconfigured channels */
456 				break;
457 			idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
458 		}
459 		data->deselect |= (idle_disconnect_pd ||
460 				   idle_disconnect_dt) << num;
461 
462 		ret = i2c_mux_add_adapter(muxc, force, num, class);
463 		if (ret)
464 			goto fail_cleanup;
465 	}
466 
467 	if (data->irq) {
468 		ret = devm_request_threaded_irq(&client->dev, data->client->irq,
469 						NULL, pca954x_irq_handler,
470 						IRQF_ONESHOT | IRQF_SHARED,
471 						"pca954x", data);
472 		if (ret)
473 			goto fail_cleanup;
474 	}
475 
476 	dev_info(&client->dev,
477 		 "registered %d multiplexed busses for I2C %s %s\n",
478 		 num, data->chip->muxtype == pca954x_ismux
479 				? "mux" : "switch", client->name);
480 
481 	return 0;
482 
483 fail_cleanup:
484 	pca954x_cleanup(muxc);
485 	return ret;
486 }
487 
488 static int pca954x_remove(struct i2c_client *client)
489 {
490 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
491 
492 	pca954x_cleanup(muxc);
493 	return 0;
494 }
495 
496 #ifdef CONFIG_PM_SLEEP
497 static int pca954x_resume(struct device *dev)
498 {
499 	struct i2c_client *client = to_i2c_client(dev);
500 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
501 	struct pca954x *data = i2c_mux_priv(muxc);
502 
503 	data->last_chan = 0;
504 	return i2c_smbus_write_byte(client, 0);
505 }
506 #endif
507 
508 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
509 
510 static struct i2c_driver pca954x_driver = {
511 	.driver		= {
512 		.name	= "pca954x",
513 		.pm	= &pca954x_pm,
514 		.of_match_table = of_match_ptr(pca954x_of_match),
515 	},
516 	.probe		= pca954x_probe,
517 	.remove		= pca954x_remove,
518 	.id_table	= pca954x_id,
519 };
520 
521 module_i2c_driver(pca954x_driver);
522 
523 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
524 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
525 MODULE_LICENSE("GPL v2");
526