summaryrefslogtreecommitdiff
path: root/drivers/i2c/muxes/i2c-mux-pca954x.c
blob: fbc748027087dbfd9783a459ccc74a7834d1a480 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/*
 * I2C multiplexer
 *
 * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
 * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
 *
 * This module supports the PCA954x and PCA954x series of I2C multiplexer/switch
 * chips made by NXP Semiconductors.
 * This includes the:
 *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
 *	 PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
 *
 * These chips are all controlled via the I2C bus itself, and all have a
 * single 8-bit register. The upstream "parent" bus fans out to two,
 * four, or eight downstream busses or channels; which of these
 * are selected is determined by the chip type and register contents. A
 * mux can select only one sub-bus at a time; a switch can select any
 * combination simultaneously.
 *
 * Based on:
 *	pca954x.c from Kumar Gala <galak@kernel.crashing.org>
 * Copyright (C) 2006
 *
 * Based on:
 *	pca954x.c from Ken Harrenstien
 * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
 *
 * Based on:
 *	i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
 * and
 *	pca9540.c from Jean Delvare <jdelvare@suse.de>.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/device.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/platform_data/pca954x.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#define PCA954X_MAX_NCHANS 8

#define PCA954X_IRQ_OFFSET 4

enum pca_type {
	pca_9540,
	pca_9542,
	pca_9543,
	pca_9544,
	pca_9545,
	pca_9546,
	pca_9547,
	pca_9548,
	pca_9846,
	pca_9847,
	pca_9848,
	pca_9849,
};

struct chip_desc {
	u8 nchans;
	u8 enable;	/* used for muxes only */
	u8 has_irq;
	enum muxtype {
		pca954x_ismux = 0,
		pca954x_isswi
	} muxtype;
	struct i2c_device_identity id;
};

struct pca954x {
	const struct chip_desc *chip;

	u8 last_chan;		/* last register value */
	u8 deselect;
	struct i2c_client *client;

	struct irq_domain *irq;
	unsigned int irq_mask;
	raw_spinlock_t lock;
};

/* Provide specs for the PCA954x types we know about */
static const struct chip_desc chips[] = {
	[pca_9540] = {
		.nchans = 2,
		.enable = 0x4,
		.muxtype = pca954x_ismux,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9542] = {
		.nchans = 2,
		.enable = 0x4,
		.has_irq = 1,
		.muxtype = pca954x_ismux,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9543] = {
		.nchans = 2,
		.has_irq = 1,
		.muxtype = pca954x_isswi,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9544] = {
		.nchans = 4,
		.enable = 0x4,
		.has_irq = 1,
		.muxtype = pca954x_ismux,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9545] = {
		.nchans = 4,
		.has_irq = 1,
		.muxtype = pca954x_isswi,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9546] = {
		.nchans = 4,
		.muxtype = pca954x_isswi,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9547] = {
		.nchans = 8,
		.enable = 0x8,
		.muxtype = pca954x_ismux,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9548] = {
		.nchans = 8,
		.muxtype = pca954x_isswi,
		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
	},
	[pca_9846] = {
		.nchans = 4,
		.muxtype = pca954x_isswi,
		.id = {
			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
			.part_id = 0x10b,
		},
	},
	[pca_9847] = {
		.nchans = 8,
		.enable = 0x8,
		.muxtype = pca954x_ismux,
		.id = {
			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
			.part_id = 0x108,
		},
	},
	[pca_9848] = {
		.nchans = 8,
		.muxtype = pca954x_isswi,
		.id = {
			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
			.part_id = 0x10a,
		},
	},
	[pca_9849] = {
		.nchans = 4,
		.enable = 0x4,
		.muxtype = pca954x_ismux,
		.id = {
			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
			.part_id = 0x109,
		},
	},
};

static const struct i2c_device_id pca954x_id[] = {
	{ "pca9540", pca_9540 },
	{ "pca9542", pca_9542 },
	{ "pca9543", pca_9543 },
	{ "pca9544", pca_9544 },
	{ "pca9545", pca_9545 },
	{ "pca9546", pca_9546 },
	{ "pca9547", pca_9547 },
	{ "pca9548", pca_9548 },
	{ "pca9846", pca_9846 },
	{ "pca9847", pca_9847 },
	{ "pca9848", pca_9848 },
	{ "pca9849", pca_9849 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pca954x_id);

#ifdef CONFIG_OF
static const struct of_device_id pca954x_of_match[] = {
	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
	{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
	{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
	{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
	{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
	{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
	{ .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
	{ .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
	{ .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
	{ .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
	{}
};
MODULE_DEVICE_TABLE(of, pca954x_of_match);
#endif

/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
   for this as they will try to lock adapter a second time */
static int pca954x_reg_write(struct i2c_adapter *adap,
			     struct i2c_client *client, u8 val)
{
	int ret = -ENODEV;

	if (adap->algo->master_xfer) {
		struct i2c_msg msg;
		char buf[1];

		msg.addr = client->addr;
		msg.flags = 0;
		msg.len = 1;
		buf[0] = val;
		msg.buf = buf;
		ret = __i2c_transfer(adap, &msg, 1);

		if (ret >= 0 && ret != 1)
			ret = -EREMOTEIO;
	} else {
		union i2c_smbus_data data;
		ret = adap->algo->smbus_xfer(adap, client->addr,
					     client->flags,
					     I2C_SMBUS_WRITE,
					     val, I2C_SMBUS_BYTE, &data);
	}

	return ret;
}

static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;
	const struct chip_desc *chip = data->chip;
	u8 regval;
	int ret = 0;

	/* we make switches look like muxes, not sure how to be smarter */
	if (chip->muxtype == pca954x_ismux)
		regval = chan | chip->enable;
	else
		regval = 1 << chan;

	/* Only select the channel if its different from the last channel */
	if (data->last_chan != regval) {
		ret = pca954x_reg_write(muxc->parent, client, regval);
		data->last_chan = ret < 0 ? 0 : regval;
	}

	return ret;
}

static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;

	if (!(data->deselect & (1 << chan)))
		return 0;

	/* Deselect active channel */
	data->last_chan = 0;
	return pca954x_reg_write(muxc->parent, client, data->last_chan);
}

static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
{
	struct pca954x *data = dev_id;
	unsigned int child_irq;
	int ret, i, handled = 0;

	ret = i2c_smbus_read_byte(data->client);
	if (ret < 0)
		return IRQ_NONE;

	for (i = 0; i < data->chip->nchans; i++) {
		if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
			child_irq = irq_linear_revmap(data->irq, i);
			handle_nested_irq(child_irq);
			handled++;
		}
	}
	return handled ? IRQ_HANDLED : IRQ_NONE;
}

static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
{
	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
		return -EINVAL;
	return 0;
}

static struct irq_chip pca954x_irq_chip = {
	.name = "i2c-mux-pca954x",
	.irq_set_type = pca954x_irq_set_type,
};

static int pca954x_irq_setup(struct i2c_mux_core *muxc)
{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;
	int c, irq;

	if (!data->chip->has_irq || client->irq <= 0)
		return 0;

	raw_spin_lock_init(&data->lock);

	data->irq = irq_domain_add_linear(client->dev.of_node,
					  data->chip->nchans,
					  &irq_domain_simple_ops, data);
	if (!data->irq)
		return -ENODEV;

	for (c = 0; c < data->chip->nchans; c++) {
		irq = irq_create_mapping(data->irq, c);
		if (!irq) {
			dev_err(&client->dev, "failed irq create map\n");
			return -EINVAL;
		}
		irq_set_chip_data(irq, data);
		irq_set_chip_and_handler(irq, &pca954x_irq_chip,
			handle_simple_irq);
	}

	return 0;
}

static void pca954x_cleanup(struct i2c_mux_core *muxc)
{
	struct pca954x *data = i2c_mux_priv(muxc);
	int c, irq;

	if (data->irq) {
		for (c = 0; c < data->chip->nchans; c++) {
			irq = irq_find_mapping(data->irq, c);
			irq_dispose_mapping(irq);
		}
		irq_domain_remove(data->irq);
	}
	i2c_mux_del_adapters(muxc);
}

/*
 * I2C init/probing/exit functions
 */
static int pca954x_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
	struct device_node *of_node = client->dev.of_node;
	bool idle_disconnect_dt;
	struct gpio_desc *gpio;
	int num, force, class;
	struct i2c_mux_core *muxc;
	struct pca954x *data;
	int ret;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
		return -ENODEV;

	muxc = i2c_mux_alloc(adap, &client->dev,
			     PCA954X_MAX_NCHANS, sizeof(*data), 0,
			     pca954x_select_chan, pca954x_deselect_mux);
	if (!muxc)
		return -ENOMEM;
	data = i2c_mux_priv(muxc);

	i2c_set_clientdata(client, muxc);
	data->client = client;

	/* Reset the mux if a reset GPIO is specified. */
	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(gpio))
		return PTR_ERR(gpio);
	if (gpio) {
		udelay(1);
		gpiod_set_value_cansleep(gpio, 0);
		/* Give the chip some time to recover. */
		udelay(1);
	}

	data->chip = of_device_get_match_data(&client->dev);
	if (!data->chip)
		data->chip = &chips[id->driver_data];

	if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
		struct i2c_device_identity id;

		ret = i2c_get_device_id(client, &id);
		if (ret && ret != -EOPNOTSUPP)
			return ret;

		if (!ret &&
		    (id.manufacturer_id != data->chip->id.manufacturer_id ||
		     id.part_id != data->chip->id.part_id)) {
			dev_warn(&client->dev,
				 "unexpected device id %03x-%03x-%x\n",
				 id.manufacturer_id, id.part_id,
				 id.die_revision);
			return -ENODEV;
		}
	}

	/* Write the mux register at addr to verify
	 * that the mux is in fact present. This also
	 * initializes the mux to disconnected state.
	 */
	if (i2c_smbus_write_byte(client, 0) < 0) {
		dev_warn(&client->dev, "probe failed\n");
		return -ENODEV;
	}

	data->last_chan = 0;		   /* force the first selection */

	idle_disconnect_dt = of_node &&
		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");

	ret = pca954x_irq_setup(muxc);
	if (ret)
		goto fail_cleanup;

	/* Now create an adapter for each channel */
	for (num = 0; num < data->chip->nchans; num++) {
		bool idle_disconnect_pd = false;

		force = 0;			  /* dynamic adap number */
		class = 0;			  /* no class by default */
		if (pdata) {
			if (num < pdata->num_modes) {
				/* force static number */
				force = pdata->modes[num].adap_id;
				class = pdata->modes[num].class;
			} else
				/* discard unconfigured channels */
				break;
			idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
		}
		data->deselect |= (idle_disconnect_pd ||
				   idle_disconnect_dt) << num;

		ret = i2c_mux_add_adapter(muxc, force, num, class);
		if (ret)
			goto fail_cleanup;
	}

	if (data->irq) {
		ret = devm_request_threaded_irq(&client->dev, data->client->irq,
						NULL, pca954x_irq_handler,
						IRQF_ONESHOT | IRQF_SHARED,
						"pca954x", data);
		if (ret)
			goto fail_cleanup;
	}

	dev_info(&client->dev,
		 "registered %d multiplexed busses for I2C %s %s\n",
		 num, data->chip->muxtype == pca954x_ismux
				? "mux" : "switch", client->name);

	return 0;

fail_cleanup:
	pca954x_cleanup(muxc);
	return ret;
}

static int pca954x_remove(struct i2c_client *client)
{
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);

	pca954x_cleanup(muxc);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pca954x_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
	struct pca954x *data = i2c_mux_priv(muxc);

	data->last_chan = 0;
	return i2c_smbus_write_byte(client, 0);
}
#endif

static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);

static struct i2c_driver pca954x_driver = {
	.driver		= {
		.name	= "pca954x",
		.pm	= &pca954x_pm,
		.of_match_table = of_match_ptr(pca954x_of_match),
	},
	.probe		= pca954x_probe,
	.remove		= pca954x_remove,
	.id_table	= pca954x_id,
};

module_i2c_driver(pca954x_driver);

MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
MODULE_LICENSE("GPL v2");