xref: /linux/drivers/pwm/pwm-pca9685.c (revision ebf68996de0ab250c5d520eb2291ab65643e9a1e) 
1 /*
2  * Driver for PCA9685 16-channel 12-bit PWM LED controller
3  *
4  * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
5  * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
6  *
7  * based on the pwm-twl-led.c driver
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License version 2 as published by
11  * the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  *
18  * You should have received a copy of the GNU General Public License along with
19  * this program.  If not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include <linux/acpi.h>
23 #include <linux/gpio/driver.h>
24 #include <linux/i2c.h>
25 #include <linux/module.h>
26 #include <linux/mutex.h>
27 #include <linux/platform_device.h>
28 #include <linux/property.h>
29 #include <linux/pwm.h>
30 #include <linux/regmap.h>
31 #include <linux/slab.h>
32 #include <linux/delay.h>
33 #include <linux/pm_runtime.h>
34 
35 /*
36  * Because the PCA9685 has only one prescaler per chip, changing the period of
37  * one channel affects the period of all 16 PWM outputs!
38  * However, the ratio between each configured duty cycle and the chip-wide
39  * period remains constant, because the OFF time is set in proportion to the
40  * counter range.
41  */
42 
43 #define PCA9685_MODE1		0x00
44 #define PCA9685_MODE2		0x01
45 #define PCA9685_SUBADDR1	0x02
46 #define PCA9685_SUBADDR2	0x03
47 #define PCA9685_SUBADDR3	0x04
48 #define PCA9685_ALLCALLADDR	0x05
49 #define PCA9685_LEDX_ON_L	0x06
50 #define PCA9685_LEDX_ON_H	0x07
51 #define PCA9685_LEDX_OFF_L	0x08
52 #define PCA9685_LEDX_OFF_H	0x09
53 
54 #define PCA9685_ALL_LED_ON_L	0xFA
55 #define PCA9685_ALL_LED_ON_H	0xFB
56 #define PCA9685_ALL_LED_OFF_L	0xFC
57 #define PCA9685_ALL_LED_OFF_H	0xFD
58 #define PCA9685_PRESCALE	0xFE
59 
60 #define PCA9685_PRESCALE_MIN	0x03	/* => max. frequency of 1526 Hz */
61 #define PCA9685_PRESCALE_MAX	0xFF	/* => min. frequency of 24 Hz */
62 
63 #define PCA9685_COUNTER_RANGE	4096
64 #define PCA9685_DEFAULT_PERIOD	5000000	/* Default period_ns = 1/200 Hz */
65 #define PCA9685_OSC_CLOCK_MHZ	25	/* Internal oscillator with 25 MHz */
66 
67 #define PCA9685_NUMREGS		0xFF
68 #define PCA9685_MAXCHAN		0x10
69 
70 #define LED_FULL		(1 << 4)
71 #define MODE1_SLEEP		(1 << 4)
72 #define MODE2_INVRT		(1 << 4)
73 #define MODE2_OUTDRV		(1 << 2)
74 
75 #define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))
76 #define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))
77 #define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))
78 #define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))
79 
80 struct pca9685 {
81 	struct pwm_chip chip;
82 	struct regmap *regmap;
83 	int duty_ns;
84 	int period_ns;
85 #if IS_ENABLED(CONFIG_GPIOLIB)
86 	struct mutex lock;
87 	struct gpio_chip gpio;
88 #endif
89 };
90 
91 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
92 {
93 	return container_of(chip, struct pca9685, chip);
94 }
95 
96 #if IS_ENABLED(CONFIG_GPIOLIB)
97 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
98 {
99 	struct pca9685 *pca = gpiochip_get_data(gpio);
100 	struct pwm_device *pwm;
101 
102 	mutex_lock(&pca->lock);
103 
104 	pwm = &pca->chip.pwms[offset];
105 
106 	if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
107 		mutex_unlock(&pca->lock);
108 		return -EBUSY;
109 	}
110 
111 	pwm_set_chip_data(pwm, (void *)1);
112 
113 	mutex_unlock(&pca->lock);
114 	pm_runtime_get_sync(pca->chip.dev);
115 	return 0;
116 }
117 
118 static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
119 {
120 	bool is_gpio = false;
121 
122 	mutex_lock(&pca->lock);
123 
124 	if (pwm->hwpwm >= PCA9685_MAXCHAN) {
125 		unsigned int i;
126 
127 		/*
128 		 * Check if any of the GPIOs are requested and in that case
129 		 * prevent using the "all LEDs" channel.
130 		 */
131 		for (i = 0; i < pca->gpio.ngpio; i++)
132 			if (gpiochip_is_requested(&pca->gpio, i)) {
133 				is_gpio = true;
134 				break;
135 			}
136 	} else if (pwm_get_chip_data(pwm)) {
137 		is_gpio = true;
138 	}
139 
140 	mutex_unlock(&pca->lock);
141 	return is_gpio;
142 }
143 
144 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
145 {
146 	struct pca9685 *pca = gpiochip_get_data(gpio);
147 	struct pwm_device *pwm = &pca->chip.pwms[offset];
148 	unsigned int value;
149 
150 	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
151 
152 	return value & LED_FULL;
153 }
154 
155 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
156 				 int value)
157 {
158 	struct pca9685 *pca = gpiochip_get_data(gpio);
159 	struct pwm_device *pwm = &pca->chip.pwms[offset];
160 	unsigned int on = value ? LED_FULL : 0;
161 
162 	/* Clear both OFF registers */
163 	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
164 	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
165 
166 	/* Set the full ON bit */
167 	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
168 }
169 
170 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
171 {
172 	struct pca9685 *pca = gpiochip_get_data(gpio);
173 	struct pwm_device *pwm;
174 
175 	pca9685_pwm_gpio_set(gpio, offset, 0);
176 	pm_runtime_put(pca->chip.dev);
177 	mutex_lock(&pca->lock);
178 	pwm = &pca->chip.pwms[offset];
179 	mutex_unlock(&pca->lock);
180 }
181 
182 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
183 					  unsigned int offset)
184 {
185 	/* Always out */
186 	return 0;
187 }
188 
189 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
190 					    unsigned int offset)
191 {
192 	return -EINVAL;
193 }
194 
195 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
196 					     unsigned int offset, int value)
197 {
198 	pca9685_pwm_gpio_set(gpio, offset, value);
199 
200 	return 0;
201 }
202 
203 /*
204  * The PCA9685 has a bit for turning the PWM output full off or on. Some
205  * boards like Intel Galileo actually uses these as normal GPIOs so we
206  * expose a GPIO chip here which can exclusively take over the underlying
207  * PWM channel.
208  */
209 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
210 {
211 	struct device *dev = pca->chip.dev;
212 
213 	mutex_init(&pca->lock);
214 
215 	pca->gpio.label = dev_name(dev);
216 	pca->gpio.parent = dev;
217 	pca->gpio.request = pca9685_pwm_gpio_request;
218 	pca->gpio.free = pca9685_pwm_gpio_free;
219 	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
220 	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
221 	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
222 	pca->gpio.get = pca9685_pwm_gpio_get;
223 	pca->gpio.set = pca9685_pwm_gpio_set;
224 	pca->gpio.base = -1;
225 	pca->gpio.ngpio = PCA9685_MAXCHAN;
226 	pca->gpio.can_sleep = true;
227 
228 	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
229 }
230 #else
231 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
232 				       struct pwm_device *pwm)
233 {
234 	return false;
235 }
236 
237 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
238 {
239 	return 0;
240 }
241 #endif
242 
243 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
244 {
245 	regmap_update_bits(pca->regmap, PCA9685_MODE1,
246 			   MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
247 	if (!enable) {
248 		/* Wait 500us for the oscillator to be back up */
249 		udelay(500);
250 	}
251 }
252 
253 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
254 			      int duty_ns, int period_ns)
255 {
256 	struct pca9685 *pca = to_pca(chip);
257 	unsigned long long duty;
258 	unsigned int reg;
259 	int prescale;
260 
261 	if (period_ns != pca->period_ns) {
262 		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
263 					     PCA9685_COUNTER_RANGE * 1000) - 1;
264 
265 		if (prescale >= PCA9685_PRESCALE_MIN &&
266 			prescale <= PCA9685_PRESCALE_MAX) {
267 			/*
268 			 * putting the chip briefly into SLEEP mode
269 			 * at this point won't interfere with the
270 			 * pm_runtime framework, because the pm_runtime
271 			 * state is guaranteed active here.
272 			 */
273 			/* Put chip into sleep mode */
274 			pca9685_set_sleep_mode(pca, true);
275 
276 			/* Change the chip-wide output frequency */
277 			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
278 
279 			/* Wake the chip up */
280 			pca9685_set_sleep_mode(pca, false);
281 
282 			pca->period_ns = period_ns;
283 		} else {
284 			dev_err(chip->dev,
285 				"prescaler not set: period out of bounds!\n");
286 			return -EINVAL;
287 		}
288 	}
289 
290 	pca->duty_ns = duty_ns;
291 
292 	if (duty_ns < 1) {
293 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
294 			reg = PCA9685_ALL_LED_OFF_H;
295 		else
296 			reg = LED_N_OFF_H(pwm->hwpwm);
297 
298 		regmap_write(pca->regmap, reg, LED_FULL);
299 
300 		return 0;
301 	}
302 
303 	if (duty_ns == period_ns) {
304 		/* Clear both OFF registers */
305 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
306 			reg = PCA9685_ALL_LED_OFF_L;
307 		else
308 			reg = LED_N_OFF_L(pwm->hwpwm);
309 
310 		regmap_write(pca->regmap, reg, 0x0);
311 
312 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
313 			reg = PCA9685_ALL_LED_OFF_H;
314 		else
315 			reg = LED_N_OFF_H(pwm->hwpwm);
316 
317 		regmap_write(pca->regmap, reg, 0x0);
318 
319 		/* Set the full ON bit */
320 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
321 			reg = PCA9685_ALL_LED_ON_H;
322 		else
323 			reg = LED_N_ON_H(pwm->hwpwm);
324 
325 		regmap_write(pca->regmap, reg, LED_FULL);
326 
327 		return 0;
328 	}
329 
330 	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
331 	duty = DIV_ROUND_UP_ULL(duty, period_ns);
332 
333 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
334 		reg = PCA9685_ALL_LED_OFF_L;
335 	else
336 		reg = LED_N_OFF_L(pwm->hwpwm);
337 
338 	regmap_write(pca->regmap, reg, (int)duty & 0xff);
339 
340 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
341 		reg = PCA9685_ALL_LED_OFF_H;
342 	else
343 		reg = LED_N_OFF_H(pwm->hwpwm);
344 
345 	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
346 
347 	/* Clear the full ON bit, otherwise the set OFF time has no effect */
348 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
349 		reg = PCA9685_ALL_LED_ON_H;
350 	else
351 		reg = LED_N_ON_H(pwm->hwpwm);
352 
353 	regmap_write(pca->regmap, reg, 0);
354 
355 	return 0;
356 }
357 
358 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
359 {
360 	struct pca9685 *pca = to_pca(chip);
361 	unsigned int reg;
362 
363 	/*
364 	 * The PWM subsystem does not support a pre-delay.
365 	 * So, set the ON-timeout to 0
366 	 */
367 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
368 		reg = PCA9685_ALL_LED_ON_L;
369 	else
370 		reg = LED_N_ON_L(pwm->hwpwm);
371 
372 	regmap_write(pca->regmap, reg, 0);
373 
374 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
375 		reg = PCA9685_ALL_LED_ON_H;
376 	else
377 		reg = LED_N_ON_H(pwm->hwpwm);
378 
379 	regmap_write(pca->regmap, reg, 0);
380 
381 	/*
382 	 * Clear the full-off bit.
383 	 * It has precedence over the others and must be off.
384 	 */
385 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
386 		reg = PCA9685_ALL_LED_OFF_H;
387 	else
388 		reg = LED_N_OFF_H(pwm->hwpwm);
389 
390 	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
391 
392 	return 0;
393 }
394 
395 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
396 {
397 	struct pca9685 *pca = to_pca(chip);
398 	unsigned int reg;
399 
400 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
401 		reg = PCA9685_ALL_LED_OFF_H;
402 	else
403 		reg = LED_N_OFF_H(pwm->hwpwm);
404 
405 	regmap_write(pca->regmap, reg, LED_FULL);
406 
407 	/* Clear the LED_OFF counter. */
408 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
409 		reg = PCA9685_ALL_LED_OFF_L;
410 	else
411 		reg = LED_N_OFF_L(pwm->hwpwm);
412 
413 	regmap_write(pca->regmap, reg, 0x0);
414 }
415 
416 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
417 {
418 	struct pca9685 *pca = to_pca(chip);
419 
420 	if (pca9685_pwm_is_gpio(pca, pwm))
421 		return -EBUSY;
422 	pm_runtime_get_sync(chip->dev);
423 
424 	return 0;
425 }
426 
427 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
428 {
429 	pca9685_pwm_disable(chip, pwm);
430 	pm_runtime_put(chip->dev);
431 }
432 
433 static const struct pwm_ops pca9685_pwm_ops = {
434 	.enable = pca9685_pwm_enable,
435 	.disable = pca9685_pwm_disable,
436 	.config = pca9685_pwm_config,
437 	.request = pca9685_pwm_request,
438 	.free = pca9685_pwm_free,
439 	.owner = THIS_MODULE,
440 };
441 
442 static const struct regmap_config pca9685_regmap_i2c_config = {
443 	.reg_bits = 8,
444 	.val_bits = 8,
445 	.max_register = PCA9685_NUMREGS,
446 	.cache_type = REGCACHE_NONE,
447 };
448 
449 static int pca9685_pwm_probe(struct i2c_client *client,
450 				const struct i2c_device_id *id)
451 {
452 	struct pca9685 *pca;
453 	int ret;
454 	int mode2;
455 
456 	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
457 	if (!pca)
458 		return -ENOMEM;
459 
460 	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
461 	if (IS_ERR(pca->regmap)) {
462 		ret = PTR_ERR(pca->regmap);
463 		dev_err(&client->dev, "Failed to initialize register map: %d\n",
464 			ret);
465 		return ret;
466 	}
467 	pca->duty_ns = 0;
468 	pca->period_ns = PCA9685_DEFAULT_PERIOD;
469 
470 	i2c_set_clientdata(client, pca);
471 
472 	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
473 
474 	if (device_property_read_bool(&client->dev, "invert"))
475 		mode2 |= MODE2_INVRT;
476 	else
477 		mode2 &= ~MODE2_INVRT;
478 
479 	if (device_property_read_bool(&client->dev, "open-drain"))
480 		mode2 &= ~MODE2_OUTDRV;
481 	else
482 		mode2 |= MODE2_OUTDRV;
483 
484 	regmap_write(pca->regmap, PCA9685_MODE2, mode2);
485 
486 	/* clear all "full off" bits */
487 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
488 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
489 
490 	pca->chip.ops = &pca9685_pwm_ops;
491 	/* add an extra channel for ALL_LED */
492 	pca->chip.npwm = PCA9685_MAXCHAN + 1;
493 
494 	pca->chip.dev = &client->dev;
495 	pca->chip.base = -1;
496 
497 	ret = pwmchip_add(&pca->chip);
498 	if (ret < 0)
499 		return ret;
500 
501 	ret = pca9685_pwm_gpio_probe(pca);
502 	if (ret < 0) {
503 		pwmchip_remove(&pca->chip);
504 		return ret;
505 	}
506 
507 	/* the chip comes out of power-up in the active state */
508 	pm_runtime_set_active(&client->dev);
509 	/*
510 	 * enable will put the chip into suspend, which is what we
511 	 * want as all outputs are disabled at this point
512 	 */
513 	pm_runtime_enable(&client->dev);
514 
515 	return 0;
516 }
517 
518 static int pca9685_pwm_remove(struct i2c_client *client)
519 {
520 	struct pca9685 *pca = i2c_get_clientdata(client);
521 	int ret;
522 
523 	ret = pwmchip_remove(&pca->chip);
524 	if (ret)
525 		return ret;
526 	pm_runtime_disable(&client->dev);
527 	return 0;
528 }
529 
530 #ifdef CONFIG_PM
531 static int pca9685_pwm_runtime_suspend(struct device *dev)
532 {
533 	struct i2c_client *client = to_i2c_client(dev);
534 	struct pca9685 *pca = i2c_get_clientdata(client);
535 
536 	pca9685_set_sleep_mode(pca, true);
537 	return 0;
538 }
539 
540 static int pca9685_pwm_runtime_resume(struct device *dev)
541 {
542 	struct i2c_client *client = to_i2c_client(dev);
543 	struct pca9685 *pca = i2c_get_clientdata(client);
544 
545 	pca9685_set_sleep_mode(pca, false);
546 	return 0;
547 }
548 #endif
549 
550 static const struct i2c_device_id pca9685_id[] = {
551 	{ "pca9685", 0 },
552 	{ /* sentinel */ },
553 };
554 MODULE_DEVICE_TABLE(i2c, pca9685_id);
555 
556 #ifdef CONFIG_ACPI
557 static const struct acpi_device_id pca9685_acpi_ids[] = {
558 	{ "INT3492", 0 },
559 	{ /* sentinel */ },
560 };
561 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
562 #endif
563 
564 #ifdef CONFIG_OF
565 static const struct of_device_id pca9685_dt_ids[] = {
566 	{ .compatible = "nxp,pca9685-pwm", },
567 	{ /* sentinel */ }
568 };
569 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
570 #endif
571 
572 static const struct dev_pm_ops pca9685_pwm_pm = {
573 	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
574 			   pca9685_pwm_runtime_resume, NULL)
575 };
576 
577 static struct i2c_driver pca9685_i2c_driver = {
578 	.driver = {
579 		.name = "pca9685-pwm",
580 		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
581 		.of_match_table = of_match_ptr(pca9685_dt_ids),
582 		.pm = &pca9685_pwm_pm,
583 	},
584 	.probe = pca9685_pwm_probe,
585 	.remove = pca9685_pwm_remove,
586 	.id_table = pca9685_id,
587 };
588 
589 module_i2c_driver(pca9685_i2c_driver);
590 
591 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
592 MODULE_DESCRIPTION("PWM driver for PCA9685");
593 MODULE_LICENSE("GPL");
594