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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#include <linux/bitmap.h>
24
25/*
26 * Because the PCA9685 has only one prescaler per chip, only the first channel
27 * that is enabled is allowed to change the prescale register.
28 * PWM channels requested afterwards must use a period that results in the same
29 * prescale setting as the one set by the first requested channel.
30 * GPIOs do not count as enabled PWMs as they are not using the prescaler.
31 */
32
33#define PCA9685_MODE1 0x00
34#define PCA9685_MODE2 0x01
35#define PCA9685_SUBADDR1 0x02
36#define PCA9685_SUBADDR2 0x03
37#define PCA9685_SUBADDR3 0x04
38#define PCA9685_ALLCALLADDR 0x05
39#define PCA9685_LEDX_ON_L 0x06
40#define PCA9685_LEDX_ON_H 0x07
41#define PCA9685_LEDX_OFF_L 0x08
42#define PCA9685_LEDX_OFF_H 0x09
43
44#define PCA9685_ALL_LED_ON_L 0xFA
45#define PCA9685_ALL_LED_ON_H 0xFB
46#define PCA9685_ALL_LED_OFF_L 0xFC
47#define PCA9685_ALL_LED_OFF_H 0xFD
48#define PCA9685_PRESCALE 0xFE
49
50#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
51#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
52
53#define PCA9685_COUNTER_RANGE 4096
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 BIT(4)
60#define MODE1_ALLCALL BIT(0)
61#define MODE1_SUB3 BIT(1)
62#define MODE1_SUB2 BIT(2)
63#define MODE1_SUB1 BIT(3)
64#define MODE1_SLEEP BIT(4)
65#define MODE2_INVRT BIT(4)
66#define MODE2_OUTDRV BIT(2)
67
68#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N)))
69#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N)))
70#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N)))
71#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N)))
72
73#define REG_ON_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_H : LED_N_ON_H((C)))
74#define REG_ON_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_L : LED_N_ON_L((C)))
75#define REG_OFF_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_H : LED_N_OFF_H((C)))
76#define REG_OFF_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_L : LED_N_OFF_L((C)))
77
78struct pca9685 {
79 struct pwm_chip chip;
80 struct regmap *regmap;
81 struct mutex lock;
82 DECLARE_BITMAP(pwms_enabled, PCA9685_MAXCHAN + 1);
83#if IS_ENABLED(CONFIG_GPIOLIB)
84 struct gpio_chip gpio;
85 DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
86#endif
87};
88
89static inline struct pca9685 *to_pca(struct pwm_chip *chip)
90{
91 return container_of(chip, struct pca9685, chip);
92}
93
94/* This function is supposed to be called with the lock mutex held */
95static bool pca9685_prescaler_can_change(struct pca9685 *pca, int channel)
96{
97 /* No PWM enabled: Change allowed */
98 if (bitmap_empty(pca->pwms_enabled, PCA9685_MAXCHAN + 1))
99 return true;
100 /* More than one PWM enabled: Change not allowed */
101 if (bitmap_weight(pca->pwms_enabled, PCA9685_MAXCHAN + 1) > 1)
102 return false;
103 /*
104 * Only one PWM enabled: Change allowed if the PWM about to
105 * be changed is the one that is already enabled
106 */
107 return test_bit(channel, pca->pwms_enabled);
108}
109
110static int pca9685_read_reg(struct pca9685 *pca, unsigned int reg, unsigned int *val)
111{
112 struct device *dev = pca->chip.dev;
113 int err;
114
115 err = regmap_read(pca->regmap, reg, val);
116 if (err)
117 dev_err(dev, "regmap_read of register 0x%x failed: %pe\n", reg, ERR_PTR(err));
118
119 return err;
120}
121
122static int pca9685_write_reg(struct pca9685 *pca, unsigned int reg, unsigned int val)
123{
124 struct device *dev = pca->chip.dev;
125 int err;
126
127 err = regmap_write(pca->regmap, reg, val);
128 if (err)
129 dev_err(dev, "regmap_write to register 0x%x failed: %pe\n", reg, ERR_PTR(err));
130
131 return err;
132}
133
134/* Helper function to set the duty cycle ratio to duty/4096 (e.g. duty=2048 -> 50%) */
135static void pca9685_pwm_set_duty(struct pca9685 *pca, int channel, unsigned int duty)
136{
137 struct pwm_device *pwm = &pca->chip.pwms[channel];
138 unsigned int on, off;
139
140 if (duty == 0) {
141 /* Set the full OFF bit, which has the highest precedence */
142 pca9685_write_reg(pca, REG_OFF_H(channel), LED_FULL);
143 return;
144 } else if (duty >= PCA9685_COUNTER_RANGE) {
145 /* Set the full ON bit and clear the full OFF bit */
146 pca9685_write_reg(pca, REG_ON_H(channel), LED_FULL);
147 pca9685_write_reg(pca, REG_OFF_H(channel), 0);
148 return;
149 }
150
151
152 if (pwm->state.usage_power && channel < PCA9685_MAXCHAN) {
153 /*
154 * If usage_power is set, the pca9685 driver will phase shift
155 * the individual channels relative to their channel number.
156 * This improves EMI because the enabled channels no longer
157 * turn on at the same time, while still maintaining the
158 * configured duty cycle / power output.
159 */
160 on = channel * PCA9685_COUNTER_RANGE / PCA9685_MAXCHAN;
161 } else
162 on = 0;
163
164 off = (on + duty) % PCA9685_COUNTER_RANGE;
165
166 /* Set ON time (clears full ON bit) */
167 pca9685_write_reg(pca, REG_ON_L(channel), on & 0xff);
168 pca9685_write_reg(pca, REG_ON_H(channel), (on >> 8) & 0xf);
169 /* Set OFF time (clears full OFF bit) */
170 pca9685_write_reg(pca, REG_OFF_L(channel), off & 0xff);
171 pca9685_write_reg(pca, REG_OFF_H(channel), (off >> 8) & 0xf);
172}
173
174static unsigned int pca9685_pwm_get_duty(struct pca9685 *pca, int channel)
175{
176 struct pwm_device *pwm = &pca->chip.pwms[channel];
177 unsigned int off = 0, on = 0, val = 0;
178
179 if (WARN_ON(channel >= PCA9685_MAXCHAN)) {
180 /* HW does not support reading state of "all LEDs" channel */
181 return 0;
182 }
183
184 pca9685_read_reg(pca, LED_N_OFF_H(channel), &off);
185 if (off & LED_FULL) {
186 /* Full OFF bit is set */
187 return 0;
188 }
189
190 pca9685_read_reg(pca, LED_N_ON_H(channel), &on);
191 if (on & LED_FULL) {
192 /* Full ON bit is set */
193 return PCA9685_COUNTER_RANGE;
194 }
195
196 pca9685_read_reg(pca, LED_N_OFF_L(channel), &val);
197 off = ((off & 0xf) << 8) | (val & 0xff);
198 if (!pwm->state.usage_power)
199 return off;
200
201 /* Read ON register to calculate duty cycle of staggered output */
202 if (pca9685_read_reg(pca, LED_N_ON_L(channel), &val)) {
203 /* Reset val to 0 in case reading LED_N_ON_L failed */
204 val = 0;
205 }
206 on = ((on & 0xf) << 8) | (val & 0xff);
207 return (off - on) & (PCA9685_COUNTER_RANGE - 1);
208}
209
210#if IS_ENABLED(CONFIG_GPIOLIB)
211static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
212{
213 bool is_inuse;
214
215 mutex_lock(&pca->lock);
216 if (pwm_idx >= PCA9685_MAXCHAN) {
217 /*
218 * "All LEDs" channel:
219 * pretend already in use if any of the PWMs are requested
220 */
221 if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
222 is_inuse = true;
223 goto out;
224 }
225 } else {
226 /*
227 * Regular channel:
228 * pretend already in use if the "all LEDs" channel is requested
229 */
230 if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
231 is_inuse = true;
232 goto out;
233 }
234 }
235 is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
236out:
237 mutex_unlock(&pca->lock);
238 return is_inuse;
239}
240
241static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
242{
243 mutex_lock(&pca->lock);
244 clear_bit(pwm_idx, pca->pwms_inuse);
245 mutex_unlock(&pca->lock);
246}
247
248static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
249{
250 struct pca9685 *pca = gpiochip_get_data(gpio);
251
252 if (pca9685_pwm_test_and_set_inuse(pca, offset))
253 return -EBUSY;
254 pm_runtime_get_sync(pca->chip.dev);
255 return 0;
256}
257
258static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
259{
260 struct pca9685 *pca = gpiochip_get_data(gpio);
261
262 return pca9685_pwm_get_duty(pca, offset) != 0;
263}
264
265static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
266 int value)
267{
268 struct pca9685 *pca = gpiochip_get_data(gpio);
269
270 pca9685_pwm_set_duty(pca, offset, value ? PCA9685_COUNTER_RANGE : 0);
271}
272
273static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
274{
275 struct pca9685 *pca = gpiochip_get_data(gpio);
276
277 pca9685_pwm_set_duty(pca, offset, 0);
278 pm_runtime_put(pca->chip.dev);
279 pca9685_pwm_clear_inuse(pca, offset);
280}
281
282static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
283 unsigned int offset)
284{
285 /* Always out */
286 return GPIO_LINE_DIRECTION_OUT;
287}
288
289static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
290 unsigned int offset)
291{
292 return -EINVAL;
293}
294
295static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
296 unsigned int offset, int value)
297{
298 pca9685_pwm_gpio_set(gpio, offset, value);
299
300 return 0;
301}
302
303/*
304 * The PCA9685 has a bit for turning the PWM output full off or on. Some
305 * boards like Intel Galileo actually uses these as normal GPIOs so we
306 * expose a GPIO chip here which can exclusively take over the underlying
307 * PWM channel.
308 */
309static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
310{
311 struct device *dev = pca->chip.dev;
312
313 pca->gpio.label = dev_name(dev);
314 pca->gpio.parent = dev;
315 pca->gpio.request = pca9685_pwm_gpio_request;
316 pca->gpio.free = pca9685_pwm_gpio_free;
317 pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
318 pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
319 pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
320 pca->gpio.get = pca9685_pwm_gpio_get;
321 pca->gpio.set = pca9685_pwm_gpio_set;
322 pca->gpio.base = -1;
323 pca->gpio.ngpio = PCA9685_MAXCHAN;
324 pca->gpio.can_sleep = true;
325
326 return devm_gpiochip_add_data(dev, &pca->gpio, pca);
327}
328#else
329static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
330 int pwm_idx)
331{
332 return false;
333}
334
335static inline void
336pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
337{
338}
339
340static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
341{
342 return 0;
343}
344#endif
345
346static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
347{
348 struct device *dev = pca->chip.dev;
349 int err = regmap_update_bits(pca->regmap, PCA9685_MODE1,
350 MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
351 if (err) {
352 dev_err(dev, "regmap_update_bits of register 0x%x failed: %pe\n",
353 PCA9685_MODE1, ERR_PTR(err));
354 return;
355 }
356
357 if (!enable) {
358 /* Wait 500us for the oscillator to be back up */
359 udelay(500);
360 }
361}
362
363static int __pca9685_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
364 const struct pwm_state *state)
365{
366 struct pca9685 *pca = to_pca(chip);
367 unsigned long long duty, prescale;
368 unsigned int val = 0;
369
370 if (state->polarity != PWM_POLARITY_NORMAL)
371 return -EINVAL;
372
373 prescale = DIV_ROUND_CLOSEST_ULL(PCA9685_OSC_CLOCK_MHZ * state->period,
374 PCA9685_COUNTER_RANGE * 1000) - 1;
375 if (prescale < PCA9685_PRESCALE_MIN || prescale > PCA9685_PRESCALE_MAX) {
376 dev_err(chip->dev, "pwm not changed: period out of bounds!\n");
377 return -EINVAL;
378 }
379
380 if (!state->enabled) {
381 pca9685_pwm_set_duty(pca, pwm->hwpwm, 0);
382 return 0;
383 }
384
385 pca9685_read_reg(pca, PCA9685_PRESCALE, &val);
386 if (prescale != val) {
387 if (!pca9685_prescaler_can_change(pca, pwm->hwpwm)) {
388 dev_err(chip->dev,
389 "pwm not changed: periods of enabled pwms must match!\n");
390 return -EBUSY;
391 }
392
393 /*
394 * Putting the chip briefly into SLEEP mode
395 * at this point won't interfere with the
396 * pm_runtime framework, because the pm_runtime
397 * state is guaranteed active here.
398 */
399 /* Put chip into sleep mode */
400 pca9685_set_sleep_mode(pca, true);
401
402 /* Change the chip-wide output frequency */
403 pca9685_write_reg(pca, PCA9685_PRESCALE, prescale);
404
405 /* Wake the chip up */
406 pca9685_set_sleep_mode(pca, false);
407 }
408
409 duty = PCA9685_COUNTER_RANGE * state->duty_cycle;
410 duty = DIV_ROUND_UP_ULL(duty, state->period);
411 pca9685_pwm_set_duty(pca, pwm->hwpwm, duty);
412 return 0;
413}
414
415static int pca9685_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
416 const struct pwm_state *state)
417{
418 struct pca9685 *pca = to_pca(chip);
419 int ret;
420
421 mutex_lock(&pca->lock);
422 ret = __pca9685_pwm_apply(chip, pwm, state);
423 if (ret == 0) {
424 if (state->enabled)
425 set_bit(pwm->hwpwm, pca->pwms_enabled);
426 else
427 clear_bit(pwm->hwpwm, pca->pwms_enabled);
428 }
429 mutex_unlock(&pca->lock);
430
431 return ret;
432}
433
434static int pca9685_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
435 struct pwm_state *state)
436{
437 struct pca9685 *pca = to_pca(chip);
438 unsigned long long duty;
439 unsigned int val = 0;
440
441 /* Calculate (chip-wide) period from prescale value */
442 pca9685_read_reg(pca, PCA9685_PRESCALE, &val);
443 /*
444 * PCA9685_OSC_CLOCK_MHZ is 25, i.e. an integer divider of 1000.
445 * The following calculation is therefore only a multiplication
446 * and we are not losing precision.
447 */
448 state->period = (PCA9685_COUNTER_RANGE * 1000 / PCA9685_OSC_CLOCK_MHZ) *
449 (val + 1);
450
451 /* The (per-channel) polarity is fixed */
452 state->polarity = PWM_POLARITY_NORMAL;
453
454 if (pwm->hwpwm >= PCA9685_MAXCHAN) {
455 /*
456 * The "all LEDs" channel does not support HW readout
457 * Return 0 and disabled for backwards compatibility
458 */
459 state->duty_cycle = 0;
460 state->enabled = false;
461 return 0;
462 }
463
464 state->enabled = true;
465 duty = pca9685_pwm_get_duty(pca, pwm->hwpwm);
466 state->duty_cycle = DIV_ROUND_DOWN_ULL(duty * state->period, PCA9685_COUNTER_RANGE);
467
468 return 0;
469}
470
471static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
472{
473 struct pca9685 *pca = to_pca(chip);
474
475 if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
476 return -EBUSY;
477
478 if (pwm->hwpwm < PCA9685_MAXCHAN) {
479 /* PWMs - except the "all LEDs" channel - default to enabled */
480 mutex_lock(&pca->lock);
481 set_bit(pwm->hwpwm, pca->pwms_enabled);
482 mutex_unlock(&pca->lock);
483 }
484
485 pm_runtime_get_sync(chip->dev);
486
487 return 0;
488}
489
490static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
491{
492 struct pca9685 *pca = to_pca(chip);
493
494 mutex_lock(&pca->lock);
495 pca9685_pwm_set_duty(pca, pwm->hwpwm, 0);
496 clear_bit(pwm->hwpwm, pca->pwms_enabled);
497 mutex_unlock(&pca->lock);
498
499 pm_runtime_put(chip->dev);
500 pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
501}
502
503static const struct pwm_ops pca9685_pwm_ops = {
504 .apply = pca9685_pwm_apply,
505 .get_state = pca9685_pwm_get_state,
506 .request = pca9685_pwm_request,
507 .free = pca9685_pwm_free,
508};
509
510static const struct regmap_config pca9685_regmap_i2c_config = {
511 .reg_bits = 8,
512 .val_bits = 8,
513 .max_register = PCA9685_NUMREGS,
514 .cache_type = REGCACHE_NONE,
515};
516
517static int pca9685_pwm_probe(struct i2c_client *client)
518{
519 struct pca9685 *pca;
520 unsigned int reg;
521 int ret;
522
523 pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
524 if (!pca)
525 return -ENOMEM;
526
527 pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
528 if (IS_ERR(pca->regmap)) {
529 ret = PTR_ERR(pca->regmap);
530 dev_err(&client->dev, "Failed to initialize register map: %d\n",
531 ret);
532 return ret;
533 }
534
535 i2c_set_clientdata(client, pca);
536
537 mutex_init(&pca->lock);
538
539 ret = pca9685_read_reg(pca, PCA9685_MODE2, ®);
540 if (ret)
541 return ret;
542
543 if (device_property_read_bool(&client->dev, "invert"))
544 reg |= MODE2_INVRT;
545 else
546 reg &= ~MODE2_INVRT;
547
548 if (device_property_read_bool(&client->dev, "open-drain"))
549 reg &= ~MODE2_OUTDRV;
550 else
551 reg |= MODE2_OUTDRV;
552
553 ret = pca9685_write_reg(pca, PCA9685_MODE2, reg);
554 if (ret)
555 return ret;
556
557 /* Disable all LED ALLCALL and SUBx addresses to avoid bus collisions */
558 pca9685_read_reg(pca, PCA9685_MODE1, ®);
559 reg &= ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3);
560 pca9685_write_reg(pca, PCA9685_MODE1, reg);
561
562 /* Reset OFF/ON registers to POR default */
563 pca9685_write_reg(pca, PCA9685_ALL_LED_OFF_L, 0);
564 pca9685_write_reg(pca, PCA9685_ALL_LED_OFF_H, LED_FULL);
565 pca9685_write_reg(pca, PCA9685_ALL_LED_ON_L, 0);
566 pca9685_write_reg(pca, PCA9685_ALL_LED_ON_H, LED_FULL);
567
568 pca->chip.ops = &pca9685_pwm_ops;
569 /* Add an extra channel for ALL_LED */
570 pca->chip.npwm = PCA9685_MAXCHAN + 1;
571
572 pca->chip.dev = &client->dev;
573
574 ret = pwmchip_add(&pca->chip);
575 if (ret < 0)
576 return ret;
577
578 ret = pca9685_pwm_gpio_probe(pca);
579 if (ret < 0) {
580 pwmchip_remove(&pca->chip);
581 return ret;
582 }
583
584 pm_runtime_enable(&client->dev);
585
586 if (pm_runtime_enabled(&client->dev)) {
587 /*
588 * Although the chip comes out of power-up in the sleep state,
589 * we force it to sleep in case it was woken up before
590 */
591 pca9685_set_sleep_mode(pca, true);
592 pm_runtime_set_suspended(&client->dev);
593 } else {
594 /* Wake the chip up if runtime PM is disabled */
595 pca9685_set_sleep_mode(pca, false);
596 }
597
598 return 0;
599}
600
601static void pca9685_pwm_remove(struct i2c_client *client)
602{
603 struct pca9685 *pca = i2c_get_clientdata(client);
604
605 pwmchip_remove(&pca->chip);
606
607 if (!pm_runtime_enabled(&client->dev)) {
608 /* Put chip in sleep state if runtime PM is disabled */
609 pca9685_set_sleep_mode(pca, true);
610 }
611
612 pm_runtime_disable(&client->dev);
613}
614
615static int __maybe_unused pca9685_pwm_runtime_suspend(struct device *dev)
616{
617 struct i2c_client *client = to_i2c_client(dev);
618 struct pca9685 *pca = i2c_get_clientdata(client);
619
620 pca9685_set_sleep_mode(pca, true);
621 return 0;
622}
623
624static int __maybe_unused pca9685_pwm_runtime_resume(struct device *dev)
625{
626 struct i2c_client *client = to_i2c_client(dev);
627 struct pca9685 *pca = i2c_get_clientdata(client);
628
629 pca9685_set_sleep_mode(pca, false);
630 return 0;
631}
632
633static const struct i2c_device_id pca9685_id[] = {
634 { "pca9685", 0 },
635 { /* sentinel */ },
636};
637MODULE_DEVICE_TABLE(i2c, pca9685_id);
638
639#ifdef CONFIG_ACPI
640static const struct acpi_device_id pca9685_acpi_ids[] = {
641 { "INT3492", 0 },
642 { /* sentinel */ },
643};
644MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
645#endif
646
647#ifdef CONFIG_OF
648static const struct of_device_id pca9685_dt_ids[] = {
649 { .compatible = "nxp,pca9685-pwm", },
650 { /* sentinel */ }
651};
652MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
653#endif
654
655static const struct dev_pm_ops pca9685_pwm_pm = {
656 SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
657 pca9685_pwm_runtime_resume, NULL)
658};
659
660static struct i2c_driver pca9685_i2c_driver = {
661 .driver = {
662 .name = "pca9685-pwm",
663 .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
664 .of_match_table = of_match_ptr(pca9685_dt_ids),
665 .pm = &pca9685_pwm_pm,
666 },
667 .probe = pca9685_pwm_probe,
668 .remove = pca9685_pwm_remove,
669 .id_table = pca9685_id,
670};
671
672module_i2c_driver(pca9685_i2c_driver);
673
674MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
675MODULE_DESCRIPTION("PWM driver for PCA9685");
676MODULE_LICENSE("GPL");
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
69struct 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
80static 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)
86static 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
107static 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
133static 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
144static 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
159static 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
171static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
172 unsigned int offset)
173{
174 /* Always out */
175 return 0;
176}
177
178static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
179 unsigned int offset)
180{
181 return -EINVAL;
182}
183
184static 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 */
198static 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
220static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
221 struct pwm_device *pwm)
222{
223 return false;
224}
225
226static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
227{
228 return 0;
229}
230#endif
231
232static 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
242static 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
347static 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
384static 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
405static 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
416static 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
422static 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
431static 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
438static 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
507static 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
520static 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
529static 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
539static const struct i2c_device_id pca9685_id[] = {
540 { "pca9685", 0 },
541 { /* sentinel */ },
542};
543MODULE_DEVICE_TABLE(i2c, pca9685_id);
544
545#ifdef CONFIG_ACPI
546static const struct acpi_device_id pca9685_acpi_ids[] = {
547 { "INT3492", 0 },
548 { /* sentinel */ },
549};
550MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
551#endif
552
553#ifdef CONFIG_OF
554static const struct of_device_id pca9685_dt_ids[] = {
555 { .compatible = "nxp,pca9685-pwm", },
556 { /* sentinel */ }
557};
558MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
559#endif
560
561static 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
566static 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
578module_i2c_driver(pca9685_i2c_driver);
579
580MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
581MODULE_DESCRIPTION("PWM driver for PCA9685");
582MODULE_LICENSE("GPL");