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
to_pca(struct pwm_chip * chip)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)
pca9685_pwm_gpio_request(struct gpio_chip * gpio,unsigned int offset)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
pca9685_pwm_is_gpio(struct pca9685 * pca,struct pwm_device * pwm)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
pca9685_pwm_gpio_get(struct gpio_chip * gpio,unsigned int offset)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
pca9685_pwm_gpio_set(struct gpio_chip * gpio,unsigned int offset,int value)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
pca9685_pwm_gpio_free(struct gpio_chip * gpio,unsigned int offset)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
pca9685_pwm_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)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
pca9685_pwm_gpio_direction_input(struct gpio_chip * gpio,unsigned int offset)178 static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
179 unsigned int offset)
180 {
181 return -EINVAL;
182 }
183
pca9685_pwm_gpio_direction_output(struct gpio_chip * gpio,unsigned int offset,int value)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 */
pca9685_pwm_gpio_probe(struct pca9685 * pca)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
pca9685_pwm_is_gpio(struct pca9685 * pca,struct pwm_device * pwm)220 static inline bool pca9685_pwm_is_gpio(struct pca9685 *pca,
221 struct pwm_device *pwm)
222 {
223 return false;
224 }
225
pca9685_pwm_gpio_probe(struct pca9685 * pca)226 static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
227 {
228 return 0;
229 }
230 #endif
231
pca9685_set_sleep_mode(struct pca9685 * pca,bool enable)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
pca9685_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)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
pca9685_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)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
pca9685_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)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
pca9685_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)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
pca9685_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)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
pca9685_pwm_probe(struct i2c_client * client,const struct i2c_device_id * id)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
pca9685_pwm_remove(struct i2c_client * client)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
pca9685_pwm_runtime_suspend(struct device * dev)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
pca9685_pwm_runtime_resume(struct device * dev)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