summaryrefslogtreecommitdiffstats
path: root/drivers/pwm/pwm-pca9685.c
blob: a7eaf962a95b15725e43426edca3bd0f4d28acf6 (plain) (blame)
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
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
/*
 * Driver for PCA9685 16-channel 12-bit PWM LED controller
 *
 * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
 * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
 *
 * based on the pwm-twl-led.c driver
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/acpi.h>
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>

/*
 * Because the PCA9685 has only one prescaler per chip, changing the period of
 * one channel affects the period of all 16 PWM outputs!
 * However, the ratio between each configured duty cycle and the chip-wide
 * period remains constant, because the OFF time is set in proportion to the
 * counter range.
 */

#define PCA9685_MODE1		0x00
#define PCA9685_MODE2		0x01
#define PCA9685_SUBADDR1	0x02
#define PCA9685_SUBADDR2	0x03
#define PCA9685_SUBADDR3	0x04
#define PCA9685_ALLCALLADDR	0x05
#define PCA9685_LEDX_ON_L	0x06
#define PCA9685_LEDX_ON_H	0x07
#define PCA9685_LEDX_OFF_L	0x08
#define PCA9685_LEDX_OFF_H	0x09

#define PCA9685_ALL_LED_ON_L	0xFA
#define PCA9685_ALL_LED_ON_H	0xFB
#define PCA9685_ALL_LED_OFF_L	0xFC
#define PCA9685_ALL_LED_OFF_H	0xFD
#define PCA9685_PRESCALE	0xFE

#define PCA9685_PRESCALE_MIN	0x03	/* => max. frequency of 1526 Hz */
#define PCA9685_PRESCALE_MAX	0xFF	/* => min. frequency of 24 Hz */

#define PCA9685_COUNTER_RANGE	4096
#define PCA9685_DEFAULT_PERIOD	5000000	/* Default period_ns = 1/200 Hz */
#define PCA9685_OSC_CLOCK_MHZ	25	/* Internal oscillator with 25 MHz */

#define PCA9685_NUMREGS		0xFF
#define PCA9685_MAXCHAN		0x10

#define LED_FULL		(1 << 4)
#define MODE1_SLEEP		(1 << 4)
#define MODE2_INVRT		(1 << 4)
#define MODE2_OUTDRV		(1 << 2)

#define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))
#define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))
#define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))
#define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))

struct pca9685 {
	struct pwm_chip chip;
	struct regmap *regmap;
	int duty_ns;
	int period_ns;
#if IS_ENABLED(CONFIG_GPIOLIB)
	struct mutex lock;
	struct gpio_chip gpio;
#endif
};

static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
	return container_of(chip, struct pca9685, chip);
}

#if IS_ENABLED(CONFIG_GPIOLIB)
static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm;

	mutex_lock(&pca->lock);

	pwm = &pca->chip.pwms[offset];

	if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
		mutex_unlock(&pca->lock);
		return -EBUSY;
	}

	pwm_set_chip_data(pwm, (void *)1);

	mutex_unlock(&pca->lock);
	pm_runtime_get_sync(pca->chip.dev);
	return 0;
}

static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
{
	bool is_gpio = false;

	mutex_lock(&pca->lock);

	if (pwm->hwpwm >= PCA9685_MAXCHAN) {
		unsigned int i;

		/*
		 * Check if any of the GPIOs are requested and in that case
		 * prevent using the "all LEDs" channel.
		 */
		for (i = 0; i < pca->gpio.ngpio; i++)
			if (gpiochip_is_requested(&pca->gpio, i)) {
				is_gpio = true;
				break;
			}
	} else if (pwm_get_chip_data(pwm)) {
		is_gpio = true;
	}

	mutex_unlock(&pca->lock);
	return is_gpio;
}

static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm = &pca->chip.pwms[offset];
	unsigned int value;

	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);

	return value & LED_FULL;
}

static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
				 int value)
{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm = &pca->chip.pwms[offset];
	unsigned int on = value ? LED_FULL : 0;

	/* Clear both OFF registers */
	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);

	/* Set the full ON bit */
	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
}

static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
{
	struct pca9685 *pca = gpiochip_get_data(gpio);
	struct pwm_device *pwm;

	pca9685_pwm_gpio_set(gpio, offset, 0);
	pm_runtime_put(pca->chip.dev);
	mutex_lock(&pca->lock);
	pwm = &pca->chip.pwms[offset];
	pwm_set_chip_data(pwm, NULL);
	mutex_unlock(&pca->lock);
}

static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
					  unsigned int offset)
{
	/* Always out */
	return 0;
}

static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
					    unsigned int offset)
{
	return -EINVAL;
}

static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
					     unsigned int offset, int value)
{
	pca9685_pwm_gpio_set(gpio, offset, value);

	return 0;
}

/*
 * The PCA9685 has a bit for turning the PWM output full off or on. Some
 * boards like Intel Galileo actually uses these as normal GPIOs so we
 * expose a GPIO chip here which can exclusively take over the underlying
 * PWM channel.
 */
static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
	struct device *dev = pca->chip.dev;

	mutex_init(&pca->lock);

	pca->gpio.label = dev_name(dev);
	pca->gpio.parent = dev;
	pca->gpio.request = pca9685_pwm_gpio_request;
	pca->gpio.free = pca9685_pwm_gpio_free;
	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
	pca->gpio.get = pca9685_pwm_gpio_get;
	pca->gpio.set = pca9685_pwm_gpio_set;
	pca->gpio.base = -1;
	pca->gpio.ngpio = PCA9685_MAXCHAN;
	pca->gpio.can_sleep = true;

	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
}
#else
static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
				       struct pwm_device *pwm)
{
	return false;
}

static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
	return 0;
}
#endif

static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
{
	regmap_update_bits(pca->regmap, PCA9685_MODE1,
			   MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
	if (!enable) {
		/* Wait 500us for the oscillator to be back up */
		udelay(500);
	}
}

static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
			      int duty_ns, int period_ns)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned long long duty;
	unsigned int reg;
	int prescale;

	if (period_ns != pca->period_ns) {
		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
					     PCA9685_COUNTER_RANGE * 1000) - 1;

		if (prescale >= PCA9685_PRESCALE_MIN &&
			prescale <= PCA9685_PRESCALE_MAX) {
			/*
			 * putting the chip briefly into SLEEP mode
			 * at this point won't interfere with the
			 * pm_runtime framework, because the pm_runtime
			 * state is guaranteed active here.
			 */
			/* Put chip into sleep mode */
			pca9685_set_sleep_mode(pca, true);

			/* Change the chip-wide output frequency */
			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);

			/* Wake the chip up */
			pca9685_set_sleep_mode(pca, false);

			pca->period_ns = period_ns;
		} else {
			dev_err(chip->dev,
				"prescaler not set: period out of bounds!\n");
			return -EINVAL;
		}
	}

	pca->duty_ns = duty_ns;

	if (duty_ns < 1) {
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_H;
		else
			reg = LED_N_OFF_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, LED_FULL);

		return 0;
	}

	if (duty_ns == period_ns) {
		/* Clear both OFF registers */
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_L;
		else
			reg = LED_N_OFF_L(pwm->hwpwm);

		regmap_write(pca->regmap, reg, 0x0);

		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_OFF_H;
		else
			reg = LED_N_OFF_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, 0x0);

		/* Set the full ON bit */
		if (pwm->hwpwm >= PCA9685_MAXCHAN)
			reg = PCA9685_ALL_LED_ON_H;
		else
			reg = LED_N_ON_H(pwm->hwpwm);

		regmap_write(pca->regmap, reg, LED_FULL);

		return 0;
	}

	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
	duty = DIV_ROUND_UP_ULL(duty, period_ns);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_L;
	else
		reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, (int)duty & 0xff);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);

	/* Clear the full ON bit, otherwise the set OFF time has no effect */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_H;
	else
		reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	return 0;
}

static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	/*
	 * The PWM subsystem does not support a pre-delay.
	 * So, set the ON-timeout to 0
	 */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_L;
	else
		reg = LED_N_ON_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_ON_H;
	else
		reg = LED_N_ON_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0);

	/*
	 * Clear the full-off bit.
	 * It has precedence over the others and must be off.
	 */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);

	return 0;
}

static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);
	unsigned int reg;

	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_H;
	else
		reg = LED_N_OFF_H(pwm->hwpwm);

	regmap_write(pca->regmap, reg, LED_FULL);

	/* Clear the LED_OFF counter. */
	if (pwm->hwpwm >= PCA9685_MAXCHAN)
		reg = PCA9685_ALL_LED_OFF_L;
	else
		reg = LED_N_OFF_L(pwm->hwpwm);

	regmap_write(pca->regmap, reg, 0x0);
}

static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
	struct pca9685 *pca = to_pca(chip);

	if (pca9685_pwm_is_gpio(pca, pwm))
		return -EBUSY;
	pm_runtime_get_sync(chip->dev);

	return 0;
}

static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
	pca9685_pwm_disable(chip, pwm);
	pm_runtime_put(chip->dev);
}

static const struct pwm_ops pca9685_pwm_ops = {
	.enable = pca9685_pwm_enable,
	.disable = pca9685_pwm_disable,
	.config = pca9685_pwm_config,
	.request = pca9685_pwm_request,
	.free = pca9685_pwm_free,
	.owner = THIS_MODULE,
};

static const struct regmap_config pca9685_regmap_i2c_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = PCA9685_NUMREGS,
	.cache_type = REGCACHE_NONE,
};

static int pca9685_pwm_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct pca9685 *pca;
	int ret;
	int mode2;

	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
	if (!pca)
		return -ENOMEM;

	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
	if (IS_ERR(pca->regmap)) {
		ret = PTR_ERR(pca->regmap);
		dev_err(&client->dev, "Failed to initialize register map: %d\n",
			ret);
		return ret;
	}
	pca->duty_ns = 0;
	pca->period_ns = PCA9685_DEFAULT_PERIOD;

	i2c_set_clientdata(client, pca);

	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);

	if (device_property_read_bool(&client->dev, "invert"))
		mode2 |= MODE2_INVRT;
	else
		mode2 &= ~MODE2_INVRT;

	if (device_property_read_bool(&client->dev, "open-drain"))
		mode2 &= ~MODE2_OUTDRV;
	else
		mode2 |= MODE2_OUTDRV;

	regmap_write(pca->regmap, PCA9685_MODE2, mode2);

	/* clear all "full off" bits */
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);

	pca->chip.ops = &pca9685_pwm_ops;
	/* add an extra channel for ALL_LED */
	pca->chip.npwm = PCA9685_MAXCHAN + 1;

	pca->chip.dev = &client->dev;
	pca->chip.base = -1;

	ret = pwmchip_add(&pca->chip);
	if (ret < 0)
		return ret;

	ret = pca9685_pwm_gpio_probe(pca);
	if (ret < 0) {
		pwmchip_remove(&pca->chip);
		return ret;
	}

	/* the chip comes out of power-up in the active state */
	pm_runtime_set_active(&client->dev);
	/*
	 * enable will put the chip into suspend, which is what we
	 * want as all outputs are disabled at this point
	 */
	pm_runtime_enable(&client->dev);

	return 0;
}

static int pca9685_pwm_remove(struct i2c_client *client)
{
	struct pca9685 *pca = i2c_get_clientdata(client);
	int ret;

	ret = pwmchip_remove(&pca->chip);
	if (ret)
		return ret;
	pm_runtime_disable(&client->dev);
	return 0;
}

#ifdef CONFIG_PM
static int pca9685_pwm_runtime_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct pca9685 *pca = i2c_get_clientdata(client);

	pca9685_set_sleep_mode(pca, true);
	return 0;
}

static int pca9685_pwm_runtime_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct pca9685 *pca = i2c_get_clientdata(client);

	pca9685_set_sleep_mode(pca, false);
	return 0;
}
#endif

static const struct i2c_device_id pca9685_id[] = {
	{ "pca9685", 0 },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(i2c, pca9685_id);

#ifdef CONFIG_ACPI
static const struct acpi_device_id pca9685_acpi_ids[] = {
	{ "INT3492", 0 },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
#endif

#ifdef CONFIG_OF
static const struct of_device_id pca9685_dt_ids[] = {
	{ .compatible = "nxp,pca9685-pwm", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
#endif

static const struct dev_pm_ops pca9685_pwm_pm = {
	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
			   pca9685_pwm_runtime_resume, NULL)
};

static struct i2c_driver pca9685_i2c_driver = {
	.driver = {
		.name = "pca9685-pwm",
		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
		.of_match_table = of_match_ptr(pca9685_dt_ids),
		.pm = &pca9685_pwm_pm,
	},
	.probe = pca9685_pwm_probe,
	.remove = pca9685_pwm_remove,
	.id_table = pca9685_id,
};

module_i2c_driver(pca9685_i2c_driver);

MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
MODULE_DESCRIPTION("PWM driver for PCA9685");
MODULE_LICENSE("GPL");