xref: /linux/drivers/pwm/pwm-pca9685.c (revision 44f57d78) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for PCA9685 16-channel 12-bit PWM LED controller
4  *
5  * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
6  * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
7  *
8  * based on the pwm-twl-led.c driver
9  */
10 
11 #include <linux/acpi.h>
12 #include <linux/gpio/driver.h>
13 #include <linux/i2c.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18 #include <linux/pwm.h>
19 #include <linux/regmap.h>
20 #include <linux/slab.h>
21 #include <linux/delay.h>
22 #include <linux/pm_runtime.h>
23 
24 /*
25  * Because the PCA9685 has only one prescaler per chip, changing the period of
26  * one channel affects the period of all 16 PWM outputs!
27  * However, the ratio between each configured duty cycle and the chip-wide
28  * period remains constant, because the OFF time is set in proportion to the
29  * counter range.
30  */
31 
32 #define PCA9685_MODE1		0x00
33 #define PCA9685_MODE2		0x01
34 #define PCA9685_SUBADDR1	0x02
35 #define PCA9685_SUBADDR2	0x03
36 #define PCA9685_SUBADDR3	0x04
37 #define PCA9685_ALLCALLADDR	0x05
38 #define PCA9685_LEDX_ON_L	0x06
39 #define PCA9685_LEDX_ON_H	0x07
40 #define PCA9685_LEDX_OFF_L	0x08
41 #define PCA9685_LEDX_OFF_H	0x09
42 
43 #define PCA9685_ALL_LED_ON_L	0xFA
44 #define PCA9685_ALL_LED_ON_H	0xFB
45 #define PCA9685_ALL_LED_OFF_L	0xFC
46 #define PCA9685_ALL_LED_OFF_H	0xFD
47 #define PCA9685_PRESCALE	0xFE
48 
49 #define PCA9685_PRESCALE_MIN	0x03	/* => max. frequency of 1526 Hz */
50 #define PCA9685_PRESCALE_MAX	0xFF	/* => min. frequency of 24 Hz */
51 
52 #define PCA9685_COUNTER_RANGE	4096
53 #define PCA9685_DEFAULT_PERIOD	5000000	/* Default period_ns = 1/200 Hz */
54 #define PCA9685_OSC_CLOCK_MHZ	25	/* Internal oscillator with 25 MHz */
55 
56 #define PCA9685_NUMREGS		0xFF
57 #define PCA9685_MAXCHAN		0x10
58 
59 #define LED_FULL		(1 << 4)
60 #define MODE1_SLEEP		(1 << 4)
61 #define MODE2_INVRT		(1 << 4)
62 #define MODE2_OUTDRV		(1 << 2)
63 
64 #define LED_N_ON_H(N)	(PCA9685_LEDX_ON_H + (4 * (N)))
65 #define LED_N_ON_L(N)	(PCA9685_LEDX_ON_L + (4 * (N)))
66 #define LED_N_OFF_H(N)	(PCA9685_LEDX_OFF_H + (4 * (N)))
67 #define LED_N_OFF_L(N)	(PCA9685_LEDX_OFF_L + (4 * (N)))
68 
69 struct pca9685 {
70 	struct pwm_chip chip;
71 	struct regmap *regmap;
72 	int duty_ns;
73 	int period_ns;
74 #if IS_ENABLED(CONFIG_GPIOLIB)
75 	struct mutex lock;
76 	struct gpio_chip gpio;
77 #endif
78 };
79 
80 static inline struct pca9685 *to_pca(struct pwm_chip *chip)
81 {
82 	return container_of(chip, struct pca9685, chip);
83 }
84 
85 #if IS_ENABLED(CONFIG_GPIOLIB)
86 static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
87 {
88 	struct pca9685 *pca = gpiochip_get_data(gpio);
89 	struct pwm_device *pwm;
90 
91 	mutex_lock(&pca->lock);
92 
93 	pwm = &pca->chip.pwms[offset];
94 
95 	if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
96 		mutex_unlock(&pca->lock);
97 		return -EBUSY;
98 	}
99 
100 	pwm_set_chip_data(pwm, (void *)1);
101 
102 	mutex_unlock(&pca->lock);
103 	pm_runtime_get_sync(pca->chip.dev);
104 	return 0;
105 }
106 
107 static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
108 {
109 	bool is_gpio = false;
110 
111 	mutex_lock(&pca->lock);
112 
113 	if (pwm->hwpwm >= PCA9685_MAXCHAN) {
114 		unsigned int i;
115 
116 		/*
117 		 * Check if any of the GPIOs are requested and in that case
118 		 * prevent using the "all LEDs" channel.
119 		 */
120 		for (i = 0; i < pca->gpio.ngpio; i++)
121 			if (gpiochip_is_requested(&pca->gpio, i)) {
122 				is_gpio = true;
123 				break;
124 			}
125 	} else if (pwm_get_chip_data(pwm)) {
126 		is_gpio = true;
127 	}
128 
129 	mutex_unlock(&pca->lock);
130 	return is_gpio;
131 }
132 
133 static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
134 {
135 	struct pca9685 *pca = gpiochip_get_data(gpio);
136 	struct pwm_device *pwm = &pca->chip.pwms[offset];
137 	unsigned int value;
138 
139 	regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
140 
141 	return value & LED_FULL;
142 }
143 
144 static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
145 				 int value)
146 {
147 	struct pca9685 *pca = gpiochip_get_data(gpio);
148 	struct pwm_device *pwm = &pca->chip.pwms[offset];
149 	unsigned int on = value ? LED_FULL : 0;
150 
151 	/* Clear both OFF registers */
152 	regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
153 	regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
154 
155 	/* Set the full ON bit */
156 	regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
157 }
158 
159 static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
160 {
161 	struct pca9685 *pca = gpiochip_get_data(gpio);
162 	struct pwm_device *pwm;
163 
164 	pca9685_pwm_gpio_set(gpio, offset, 0);
165 	pm_runtime_put(pca->chip.dev);
166 	mutex_lock(&pca->lock);
167 	pwm = &pca->chip.pwms[offset];
168 	mutex_unlock(&pca->lock);
169 }
170 
171 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
172 					  unsigned int offset)
173 {
174 	/* Always out */
175 	return 0;
176 }
177 
178 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
179 					    unsigned int offset)
180 {
181 	return -EINVAL;
182 }
183 
184 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
185 					     unsigned int offset, int value)
186 {
187 	pca9685_pwm_gpio_set(gpio, offset, value);
188 
189 	return 0;
190 }
191 
192 /*
193  * The PCA9685 has a bit for turning the PWM output full off or on. Some
194  * boards like Intel Galileo actually uses these as normal GPIOs so we
195  * expose a GPIO chip here which can exclusively take over the underlying
196  * PWM channel.
197  */
198 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
199 {
200 	struct device *dev = pca->chip.dev;
201 
202 	mutex_init(&pca->lock);
203 
204 	pca->gpio.label = dev_name(dev);
205 	pca->gpio.parent = dev;
206 	pca->gpio.request = pca9685_pwm_gpio_request;
207 	pca->gpio.free = pca9685_pwm_gpio_free;
208 	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
209 	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
210 	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
211 	pca->gpio.get = pca9685_pwm_gpio_get;
212 	pca->gpio.set = pca9685_pwm_gpio_set;
213 	pca->gpio.base = -1;
214 	pca->gpio.ngpio = PCA9685_MAXCHAN;
215 	pca->gpio.can_sleep = true;
216 
217 	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
218 }
219 #else
220 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
221 				       struct pwm_device *pwm)
222 {
223 	return false;
224 }
225 
226 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
227 {
228 	return 0;
229 }
230 #endif
231 
232 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
233 {
234 	regmap_update_bits(pca->regmap, PCA9685_MODE1,
235 			   MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
236 	if (!enable) {
237 		/* Wait 500us for the oscillator to be back up */
238 		udelay(500);
239 	}
240 }
241 
242 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
243 			      int duty_ns, int period_ns)
244 {
245 	struct pca9685 *pca = to_pca(chip);
246 	unsigned long long duty;
247 	unsigned int reg;
248 	int prescale;
249 
250 	if (period_ns != pca->period_ns) {
251 		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
252 					     PCA9685_COUNTER_RANGE * 1000) - 1;
253 
254 		if (prescale >= PCA9685_PRESCALE_MIN &&
255 			prescale <= PCA9685_PRESCALE_MAX) {
256 			/*
257 			 * putting the chip briefly into SLEEP mode
258 			 * at this point won't interfere with the
259 			 * pm_runtime framework, because the pm_runtime
260 			 * state is guaranteed active here.
261 			 */
262 			/* Put chip into sleep mode */
263 			pca9685_set_sleep_mode(pca, true);
264 
265 			/* Change the chip-wide output frequency */
266 			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
267 
268 			/* Wake the chip up */
269 			pca9685_set_sleep_mode(pca, false);
270 
271 			pca->period_ns = period_ns;
272 		} else {
273 			dev_err(chip->dev,
274 				"prescaler not set: period out of bounds!\n");
275 			return -EINVAL;
276 		}
277 	}
278 
279 	pca->duty_ns = duty_ns;
280 
281 	if (duty_ns < 1) {
282 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
283 			reg = PCA9685_ALL_LED_OFF_H;
284 		else
285 			reg = LED_N_OFF_H(pwm->hwpwm);
286 
287 		regmap_write(pca->regmap, reg, LED_FULL);
288 
289 		return 0;
290 	}
291 
292 	if (duty_ns == period_ns) {
293 		/* Clear both OFF registers */
294 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
295 			reg = PCA9685_ALL_LED_OFF_L;
296 		else
297 			reg = LED_N_OFF_L(pwm->hwpwm);
298 
299 		regmap_write(pca->regmap, reg, 0x0);
300 
301 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
302 			reg = PCA9685_ALL_LED_OFF_H;
303 		else
304 			reg = LED_N_OFF_H(pwm->hwpwm);
305 
306 		regmap_write(pca->regmap, reg, 0x0);
307 
308 		/* Set the full ON bit */
309 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
310 			reg = PCA9685_ALL_LED_ON_H;
311 		else
312 			reg = LED_N_ON_H(pwm->hwpwm);
313 
314 		regmap_write(pca->regmap, reg, LED_FULL);
315 
316 		return 0;
317 	}
318 
319 	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
320 	duty = DIV_ROUND_UP_ULL(duty, period_ns);
321 
322 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
323 		reg = PCA9685_ALL_LED_OFF_L;
324 	else
325 		reg = LED_N_OFF_L(pwm->hwpwm);
326 
327 	regmap_write(pca->regmap, reg, (int)duty & 0xff);
328 
329 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
330 		reg = PCA9685_ALL_LED_OFF_H;
331 	else
332 		reg = LED_N_OFF_H(pwm->hwpwm);
333 
334 	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
335 
336 	/* Clear the full ON bit, otherwise the set OFF time has no effect */
337 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
338 		reg = PCA9685_ALL_LED_ON_H;
339 	else
340 		reg = LED_N_ON_H(pwm->hwpwm);
341 
342 	regmap_write(pca->regmap, reg, 0);
343 
344 	return 0;
345 }
346 
347 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
348 {
349 	struct pca9685 *pca = to_pca(chip);
350 	unsigned int reg;
351 
352 	/*
353 	 * The PWM subsystem does not support a pre-delay.
354 	 * So, set the ON-timeout to 0
355 	 */
356 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
357 		reg = PCA9685_ALL_LED_ON_L;
358 	else
359 		reg = LED_N_ON_L(pwm->hwpwm);
360 
361 	regmap_write(pca->regmap, reg, 0);
362 
363 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
364 		reg = PCA9685_ALL_LED_ON_H;
365 	else
366 		reg = LED_N_ON_H(pwm->hwpwm);
367 
368 	regmap_write(pca->regmap, reg, 0);
369 
370 	/*
371 	 * Clear the full-off bit.
372 	 * It has precedence over the others and must be off.
373 	 */
374 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
375 		reg = PCA9685_ALL_LED_OFF_H;
376 	else
377 		reg = LED_N_OFF_H(pwm->hwpwm);
378 
379 	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
380 
381 	return 0;
382 }
383 
384 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
385 {
386 	struct pca9685 *pca = to_pca(chip);
387 	unsigned int reg;
388 
389 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
390 		reg = PCA9685_ALL_LED_OFF_H;
391 	else
392 		reg = LED_N_OFF_H(pwm->hwpwm);
393 
394 	regmap_write(pca->regmap, reg, LED_FULL);
395 
396 	/* Clear the LED_OFF counter. */
397 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
398 		reg = PCA9685_ALL_LED_OFF_L;
399 	else
400 		reg = LED_N_OFF_L(pwm->hwpwm);
401 
402 	regmap_write(pca->regmap, reg, 0x0);
403 }
404 
405 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
406 {
407 	struct pca9685 *pca = to_pca(chip);
408 
409 	if (pca9685_pwm_is_gpio(pca, pwm))
410 		return -EBUSY;
411 	pm_runtime_get_sync(chip->dev);
412 
413 	return 0;
414 }
415 
416 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
417 {
418 	pca9685_pwm_disable(chip, pwm);
419 	pm_runtime_put(chip->dev);
420 }
421 
422 static const struct pwm_ops pca9685_pwm_ops = {
423 	.enable = pca9685_pwm_enable,
424 	.disable = pca9685_pwm_disable,
425 	.config = pca9685_pwm_config,
426 	.request = pca9685_pwm_request,
427 	.free = pca9685_pwm_free,
428 	.owner = THIS_MODULE,
429 };
430 
431 static const struct regmap_config pca9685_regmap_i2c_config = {
432 	.reg_bits = 8,
433 	.val_bits = 8,
434 	.max_register = PCA9685_NUMREGS,
435 	.cache_type = REGCACHE_NONE,
436 };
437 
438 static int pca9685_pwm_probe(struct i2c_client *client,
439 				const struct i2c_device_id *id)
440 {
441 	struct pca9685 *pca;
442 	int ret;
443 	int mode2;
444 
445 	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
446 	if (!pca)
447 		return -ENOMEM;
448 
449 	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
450 	if (IS_ERR(pca->regmap)) {
451 		ret = PTR_ERR(pca->regmap);
452 		dev_err(&client->dev, "Failed to initialize register map: %d\n",
453 			ret);
454 		return ret;
455 	}
456 	pca->duty_ns = 0;
457 	pca->period_ns = PCA9685_DEFAULT_PERIOD;
458 
459 	i2c_set_clientdata(client, pca);
460 
461 	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
462 
463 	if (device_property_read_bool(&client->dev, "invert"))
464 		mode2 |= MODE2_INVRT;
465 	else
466 		mode2 &= ~MODE2_INVRT;
467 
468 	if (device_property_read_bool(&client->dev, "open-drain"))
469 		mode2 &= ~MODE2_OUTDRV;
470 	else
471 		mode2 |= MODE2_OUTDRV;
472 
473 	regmap_write(pca->regmap, PCA9685_MODE2, mode2);
474 
475 	/* clear all "full off" bits */
476 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
477 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
478 
479 	pca->chip.ops = &pca9685_pwm_ops;
480 	/* add an extra channel for ALL_LED */
481 	pca->chip.npwm = PCA9685_MAXCHAN + 1;
482 
483 	pca->chip.dev = &client->dev;
484 	pca->chip.base = -1;
485 
486 	ret = pwmchip_add(&pca->chip);
487 	if (ret < 0)
488 		return ret;
489 
490 	ret = pca9685_pwm_gpio_probe(pca);
491 	if (ret < 0) {
492 		pwmchip_remove(&pca->chip);
493 		return ret;
494 	}
495 
496 	/* the chip comes out of power-up in the active state */
497 	pm_runtime_set_active(&client->dev);
498 	/*
499 	 * enable will put the chip into suspend, which is what we
500 	 * want as all outputs are disabled at this point
501 	 */
502 	pm_runtime_enable(&client->dev);
503 
504 	return 0;
505 }
506 
507 static int pca9685_pwm_remove(struct i2c_client *client)
508 {
509 	struct pca9685 *pca = i2c_get_clientdata(client);
510 	int ret;
511 
512 	ret = pwmchip_remove(&pca->chip);
513 	if (ret)
514 		return ret;
515 	pm_runtime_disable(&client->dev);
516 	return 0;
517 }
518 
519 #ifdef CONFIG_PM
520 static int pca9685_pwm_runtime_suspend(struct device *dev)
521 {
522 	struct i2c_client *client = to_i2c_client(dev);
523 	struct pca9685 *pca = i2c_get_clientdata(client);
524 
525 	pca9685_set_sleep_mode(pca, true);
526 	return 0;
527 }
528 
529 static int pca9685_pwm_runtime_resume(struct device *dev)
530 {
531 	struct i2c_client *client = to_i2c_client(dev);
532 	struct pca9685 *pca = i2c_get_clientdata(client);
533 
534 	pca9685_set_sleep_mode(pca, false);
535 	return 0;
536 }
537 #endif
538 
539 static const struct i2c_device_id pca9685_id[] = {
540 	{ "pca9685", 0 },
541 	{ /* sentinel */ },
542 };
543 MODULE_DEVICE_TABLE(i2c, pca9685_id);
544 
545 #ifdef CONFIG_ACPI
546 static const struct acpi_device_id pca9685_acpi_ids[] = {
547 	{ "INT3492", 0 },
548 	{ /* sentinel */ },
549 };
550 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
551 #endif
552 
553 #ifdef CONFIG_OF
554 static const struct of_device_id pca9685_dt_ids[] = {
555 	{ .compatible = "nxp,pca9685-pwm", },
556 	{ /* sentinel */ }
557 };
558 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
559 #endif
560 
561 static const struct dev_pm_ops pca9685_pwm_pm = {
562 	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
563 			   pca9685_pwm_runtime_resume, NULL)
564 };
565 
566 static struct i2c_driver pca9685_i2c_driver = {
567 	.driver = {
568 		.name = "pca9685-pwm",
569 		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
570 		.of_match_table = of_match_ptr(pca9685_dt_ids),
571 		.pm = &pca9685_pwm_pm,
572 	},
573 	.probe = pca9685_pwm_probe,
574 	.remove = pca9685_pwm_remove,
575 	.id_table = pca9685_id,
576 };
577 
578 module_i2c_driver(pca9685_i2c_driver);
579 
580 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
581 MODULE_DESCRIPTION("PWM driver for PCA9685");
582 MODULE_LICENSE("GPL");
583