xref: /openbmc/linux/drivers/pwm/pwm-pca9685.c (revision ba61bb17) 
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 	pwm_set_chip_data(pwm, NULL);
180 	mutex_unlock(&pca->lock);
181 }
182 
183 static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
184 					  unsigned int offset)
185 {
186 	/* Always out */
187 	return 0;
188 }
189 
190 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
191 					    unsigned int offset)
192 {
193 	return -EINVAL;
194 }
195 
196 static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
197 					     unsigned int offset, int value)
198 {
199 	pca9685_pwm_gpio_set(gpio, offset, value);
200 
201 	return 0;
202 }
203 
204 /*
205  * The PCA9685 has a bit for turning the PWM output full off or on. Some
206  * boards like Intel Galileo actually uses these as normal GPIOs so we
207  * expose a GPIO chip here which can exclusively take over the underlying
208  * PWM channel.
209  */
210 static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
211 {
212 	struct device *dev = pca->chip.dev;
213 
214 	mutex_init(&pca->lock);
215 
216 	pca->gpio.label = dev_name(dev);
217 	pca->gpio.parent = dev;
218 	pca->gpio.request = pca9685_pwm_gpio_request;
219 	pca->gpio.free = pca9685_pwm_gpio_free;
220 	pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
221 	pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
222 	pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
223 	pca->gpio.get = pca9685_pwm_gpio_get;
224 	pca->gpio.set = pca9685_pwm_gpio_set;
225 	pca->gpio.base = -1;
226 	pca->gpio.ngpio = PCA9685_MAXCHAN;
227 	pca->gpio.can_sleep = true;
228 
229 	return devm_gpiochip_add_data(dev, &pca->gpio, pca);
230 }
231 #else
232 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
233 				       struct pwm_device *pwm)
234 {
235 	return false;
236 }
237 
238 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
239 {
240 	return 0;
241 }
242 #endif
243 
244 static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
245 {
246 	regmap_update_bits(pca->regmap, PCA9685_MODE1,
247 			   MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
248 	if (!enable) {
249 		/* Wait 500us for the oscillator to be back up */
250 		udelay(500);
251 	}
252 }
253 
254 static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
255 			      int duty_ns, int period_ns)
256 {
257 	struct pca9685 *pca = to_pca(chip);
258 	unsigned long long duty;
259 	unsigned int reg;
260 	int prescale;
261 
262 	if (period_ns != pca->period_ns) {
263 		prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
264 					     PCA9685_COUNTER_RANGE * 1000) - 1;
265 
266 		if (prescale >= PCA9685_PRESCALE_MIN &&
267 			prescale <= PCA9685_PRESCALE_MAX) {
268 			/*
269 			 * putting the chip briefly into SLEEP mode
270 			 * at this point won't interfere with the
271 			 * pm_runtime framework, because the pm_runtime
272 			 * state is guaranteed active here.
273 			 */
274 			/* Put chip into sleep mode */
275 			pca9685_set_sleep_mode(pca, true);
276 
277 			/* Change the chip-wide output frequency */
278 			regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
279 
280 			/* Wake the chip up */
281 			pca9685_set_sleep_mode(pca, false);
282 
283 			pca->period_ns = period_ns;
284 		} else {
285 			dev_err(chip->dev,
286 				"prescaler not set: period out of bounds!\n");
287 			return -EINVAL;
288 		}
289 	}
290 
291 	pca->duty_ns = duty_ns;
292 
293 	if (duty_ns < 1) {
294 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
295 			reg = PCA9685_ALL_LED_OFF_H;
296 		else
297 			reg = LED_N_OFF_H(pwm->hwpwm);
298 
299 		regmap_write(pca->regmap, reg, LED_FULL);
300 
301 		return 0;
302 	}
303 
304 	if (duty_ns == period_ns) {
305 		/* Clear both OFF registers */
306 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
307 			reg = PCA9685_ALL_LED_OFF_L;
308 		else
309 			reg = LED_N_OFF_L(pwm->hwpwm);
310 
311 		regmap_write(pca->regmap, reg, 0x0);
312 
313 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
314 			reg = PCA9685_ALL_LED_OFF_H;
315 		else
316 			reg = LED_N_OFF_H(pwm->hwpwm);
317 
318 		regmap_write(pca->regmap, reg, 0x0);
319 
320 		/* Set the full ON bit */
321 		if (pwm->hwpwm >= PCA9685_MAXCHAN)
322 			reg = PCA9685_ALL_LED_ON_H;
323 		else
324 			reg = LED_N_ON_H(pwm->hwpwm);
325 
326 		regmap_write(pca->regmap, reg, LED_FULL);
327 
328 		return 0;
329 	}
330 
331 	duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
332 	duty = DIV_ROUND_UP_ULL(duty, period_ns);
333 
334 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
335 		reg = PCA9685_ALL_LED_OFF_L;
336 	else
337 		reg = LED_N_OFF_L(pwm->hwpwm);
338 
339 	regmap_write(pca->regmap, reg, (int)duty & 0xff);
340 
341 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
342 		reg = PCA9685_ALL_LED_OFF_H;
343 	else
344 		reg = LED_N_OFF_H(pwm->hwpwm);
345 
346 	regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
347 
348 	/* Clear the full ON bit, otherwise the set OFF time has no effect */
349 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
350 		reg = PCA9685_ALL_LED_ON_H;
351 	else
352 		reg = LED_N_ON_H(pwm->hwpwm);
353 
354 	regmap_write(pca->regmap, reg, 0);
355 
356 	return 0;
357 }
358 
359 static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
360 {
361 	struct pca9685 *pca = to_pca(chip);
362 	unsigned int reg;
363 
364 	/*
365 	 * The PWM subsystem does not support a pre-delay.
366 	 * So, set the ON-timeout to 0
367 	 */
368 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
369 		reg = PCA9685_ALL_LED_ON_L;
370 	else
371 		reg = LED_N_ON_L(pwm->hwpwm);
372 
373 	regmap_write(pca->regmap, reg, 0);
374 
375 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
376 		reg = PCA9685_ALL_LED_ON_H;
377 	else
378 		reg = LED_N_ON_H(pwm->hwpwm);
379 
380 	regmap_write(pca->regmap, reg, 0);
381 
382 	/*
383 	 * Clear the full-off bit.
384 	 * It has precedence over the others and must be off.
385 	 */
386 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
387 		reg = PCA9685_ALL_LED_OFF_H;
388 	else
389 		reg = LED_N_OFF_H(pwm->hwpwm);
390 
391 	regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
392 
393 	return 0;
394 }
395 
396 static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
397 {
398 	struct pca9685 *pca = to_pca(chip);
399 	unsigned int reg;
400 
401 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
402 		reg = PCA9685_ALL_LED_OFF_H;
403 	else
404 		reg = LED_N_OFF_H(pwm->hwpwm);
405 
406 	regmap_write(pca->regmap, reg, LED_FULL);
407 
408 	/* Clear the LED_OFF counter. */
409 	if (pwm->hwpwm >= PCA9685_MAXCHAN)
410 		reg = PCA9685_ALL_LED_OFF_L;
411 	else
412 		reg = LED_N_OFF_L(pwm->hwpwm);
413 
414 	regmap_write(pca->regmap, reg, 0x0);
415 }
416 
417 static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
418 {
419 	struct pca9685 *pca = to_pca(chip);
420 
421 	if (pca9685_pwm_is_gpio(pca, pwm))
422 		return -EBUSY;
423 	pm_runtime_get_sync(chip->dev);
424 
425 	return 0;
426 }
427 
428 static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
429 {
430 	pca9685_pwm_disable(chip, pwm);
431 	pm_runtime_put(chip->dev);
432 }
433 
434 static const struct pwm_ops pca9685_pwm_ops = {
435 	.enable = pca9685_pwm_enable,
436 	.disable = pca9685_pwm_disable,
437 	.config = pca9685_pwm_config,
438 	.request = pca9685_pwm_request,
439 	.free = pca9685_pwm_free,
440 	.owner = THIS_MODULE,
441 };
442 
443 static const struct regmap_config pca9685_regmap_i2c_config = {
444 	.reg_bits = 8,
445 	.val_bits = 8,
446 	.max_register = PCA9685_NUMREGS,
447 	.cache_type = REGCACHE_NONE,
448 };
449 
450 static int pca9685_pwm_probe(struct i2c_client *client,
451 				const struct i2c_device_id *id)
452 {
453 	struct pca9685 *pca;
454 	int ret;
455 	int mode2;
456 
457 	pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
458 	if (!pca)
459 		return -ENOMEM;
460 
461 	pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
462 	if (IS_ERR(pca->regmap)) {
463 		ret = PTR_ERR(pca->regmap);
464 		dev_err(&client->dev, "Failed to initialize register map: %d\n",
465 			ret);
466 		return ret;
467 	}
468 	pca->duty_ns = 0;
469 	pca->period_ns = PCA9685_DEFAULT_PERIOD;
470 
471 	i2c_set_clientdata(client, pca);
472 
473 	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
474 
475 	if (device_property_read_bool(&client->dev, "invert"))
476 		mode2 |= MODE2_INVRT;
477 	else
478 		mode2 &= ~MODE2_INVRT;
479 
480 	if (device_property_read_bool(&client->dev, "open-drain"))
481 		mode2 &= ~MODE2_OUTDRV;
482 	else
483 		mode2 |= MODE2_OUTDRV;
484 
485 	regmap_write(pca->regmap, PCA9685_MODE2, mode2);
486 
487 	/* clear all "full off" bits */
488 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
489 	regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
490 
491 	pca->chip.ops = &pca9685_pwm_ops;
492 	/* add an extra channel for ALL_LED */
493 	pca->chip.npwm = PCA9685_MAXCHAN + 1;
494 
495 	pca->chip.dev = &client->dev;
496 	pca->chip.base = -1;
497 
498 	ret = pwmchip_add(&pca->chip);
499 	if (ret < 0)
500 		return ret;
501 
502 	ret = pca9685_pwm_gpio_probe(pca);
503 	if (ret < 0) {
504 		pwmchip_remove(&pca->chip);
505 		return ret;
506 	}
507 
508 	/* the chip comes out of power-up in the active state */
509 	pm_runtime_set_active(&client->dev);
510 	/*
511 	 * enable will put the chip into suspend, which is what we
512 	 * want as all outputs are disabled at this point
513 	 */
514 	pm_runtime_enable(&client->dev);
515 
516 	return 0;
517 }
518 
519 static int pca9685_pwm_remove(struct i2c_client *client)
520 {
521 	struct pca9685 *pca = i2c_get_clientdata(client);
522 	int ret;
523 
524 	ret = pwmchip_remove(&pca->chip);
525 	if (ret)
526 		return ret;
527 	pm_runtime_disable(&client->dev);
528 	return 0;
529 }
530 
531 #ifdef CONFIG_PM
532 static int pca9685_pwm_runtime_suspend(struct device *dev)
533 {
534 	struct i2c_client *client = to_i2c_client(dev);
535 	struct pca9685 *pca = i2c_get_clientdata(client);
536 
537 	pca9685_set_sleep_mode(pca, true);
538 	return 0;
539 }
540 
541 static int pca9685_pwm_runtime_resume(struct device *dev)
542 {
543 	struct i2c_client *client = to_i2c_client(dev);
544 	struct pca9685 *pca = i2c_get_clientdata(client);
545 
546 	pca9685_set_sleep_mode(pca, false);
547 	return 0;
548 }
549 #endif
550 
551 static const struct i2c_device_id pca9685_id[] = {
552 	{ "pca9685", 0 },
553 	{ /* sentinel */ },
554 };
555 MODULE_DEVICE_TABLE(i2c, pca9685_id);
556 
557 #ifdef CONFIG_ACPI
558 static const struct acpi_device_id pca9685_acpi_ids[] = {
559 	{ "INT3492", 0 },
560 	{ /* sentinel */ },
561 };
562 MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
563 #endif
564 
565 #ifdef CONFIG_OF
566 static const struct of_device_id pca9685_dt_ids[] = {
567 	{ .compatible = "nxp,pca9685-pwm", },
568 	{ /* sentinel */ }
569 };
570 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
571 #endif
572 
573 static const struct dev_pm_ops pca9685_pwm_pm = {
574 	SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
575 			   pca9685_pwm_runtime_resume, NULL)
576 };
577 
578 static struct i2c_driver pca9685_i2c_driver = {
579 	.driver = {
580 		.name = "pca9685-pwm",
581 		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
582 		.of_match_table = of_match_ptr(pca9685_dt_ids),
583 		.pm = &pca9685_pwm_pm,
584 	},
585 	.probe = pca9685_pwm_probe,
586 	.remove = pca9685_pwm_remove,
587 	.id_table = pca9685_id,
588 };
589 
590 module_i2c_driver(pca9685_i2c_driver);
591 
592 MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
593 MODULE_DESCRIPTION("PWM driver for PCA9685");
594 MODULE_LICENSE("GPL");
595