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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 <[email protected]>
6 * Copyright (C) 2015 Clemens Gruber <[email protected]>
7 *
8 * based on the pwm-twl-led.c driver
9 */
10
11#include <linux/gpio/driver.h>
12#include <linux/i2c.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/platform_device.h>
16#include <linux/property.h>
17#include <linux/pwm.h>
18#include <linux/regmap.h>
19#include <linux/slab.h>
20#include <linux/delay.h>
21#include <linux/pm_runtime.h>
22#include <linux/bitmap.h>
23
24/*
25 * Because the PCA9685 has only one prescaler per chip, only the first channel
26 * that is enabled is allowed to change the prescale register.
27 * PWM channels requested afterwards must use a period that results in the same
28 * prescale setting as the one set by the first requested channel.
29 */
30
31#define PCA9685_MODE1 0x00
32#define PCA9685_MODE2 0x01
33#define PCA9685_SUBADDR1 0x02
34#define PCA9685_SUBADDR2 0x03
35#define PCA9685_SUBADDR3 0x04
36#define PCA9685_ALLCALLADDR 0x05
37#define PCA9685_LEDX_ON_L 0x06
38#define PCA9685_LEDX_ON_H 0x07
39#define PCA9685_LEDX_OFF_L 0x08
40#define PCA9685_LEDX_OFF_H 0x09
41
42#define PCA9685_ALL_LED_ON_L 0xFA
43#define PCA9685_ALL_LED_ON_H 0xFB
44#define PCA9685_ALL_LED_OFF_L 0xFC
45#define PCA9685_ALL_LED_OFF_H 0xFD
46#define PCA9685_PRESCALE 0xFE
47
48#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
49#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
50
51#define PCA9685_COUNTER_RANGE 4096
52#define PCA9685_OSC_CLOCK_HZ 25000000 /* Internal oscillator with 25 MHz */
53
54/*
55 * The time value of one counter tick. Note that NSEC_PER_SEC is an integer
56 * multiple of PCA9685_OSC_CLOCK_HZ, so there is no rounding involved and we're
57 * not loosing precision due to the early division.
58 */
59#define PCA9685_QUANTUM_NS(_prescale) ((NSEC_PER_SEC / PCA9685_OSC_CLOCK_HZ) * (_prescale + 1))
60
61#define PCA9685_NUMREGS 0xFF
62#define PCA9685_MAXCHAN 0x10
63
64#define LED_FULL BIT(4)
65#define MODE1_ALLCALL BIT(0)
66#define MODE1_SUB3 BIT(1)
67#define MODE1_SUB2 BIT(2)
68#define MODE1_SUB1 BIT(3)
69#define MODE1_SLEEP BIT(4)
70#define MODE1_AI BIT(5)
71
72#define MODE2_INVRT BIT(4)
73#define MODE2_OUTDRV BIT(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#define REG_ON_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_H : LED_N_ON_H((C)))
81#define REG_ON_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_L : LED_N_ON_L((C)))
82#define REG_OFF_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_H : LED_N_OFF_H((C)))
83#define REG_OFF_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_L : LED_N_OFF_L((C)))
84
85struct pca9685 {
86 struct regmap *regmap;
87 struct mutex lock;
88 DECLARE_BITMAP(pwms_enabled, PCA9685_MAXCHAN + 1);
89};
90
91static inline struct pca9685 *to_pca(struct pwm_chip *chip)
92{
93 return pwmchip_get_drvdata(chip);
94}
95
96/* This function is supposed to be called with the lock mutex held */
97static bool pca9685_prescaler_can_change(struct pca9685 *pca, int channel)
98{
99 /* No PWM enabled: Change allowed */
100 if (bitmap_empty(pca->pwms_enabled, PCA9685_MAXCHAN + 1))
101 return true;
102 /* More than one PWM enabled: Change not allowed */
103 if (bitmap_weight(pca->pwms_enabled, PCA9685_MAXCHAN + 1) > 1)
104 return false;
105 /*
106 * Only one PWM enabled: Change allowed if the PWM about to
107 * be changed is the one that is already enabled
108 */
109 return test_bit(channel, pca->pwms_enabled);
110}
111
112static int pca9685_read_reg(struct pwm_chip *chip, unsigned int reg, unsigned int *val)
113{
114 struct pca9685 *pca = to_pca(chip);
115 struct device *dev = pwmchip_parent(chip);
116 int err;
117
118 err = regmap_read(pca->regmap, reg, val);
119 if (err)
120 dev_err(dev, "regmap_read of register 0x%x failed: %pe\n", reg, ERR_PTR(err));
121
122 return err;
123}
124
125static int pca9685_write_reg(struct pwm_chip *chip, unsigned int reg, unsigned int val)
126{
127 struct pca9685 *pca = to_pca(chip);
128 struct device *dev = pwmchip_parent(chip);
129 int err;
130
131 err = regmap_write(pca->regmap, reg, val);
132 if (err)
133 dev_err(dev, "regmap_write to register 0x%x failed: %pe\n", reg, ERR_PTR(err));
134
135 return err;
136}
137
138static int pca9685_write_4reg(struct pwm_chip *chip, unsigned int reg, u8 val[4])
139{
140 struct pca9685 *pca = to_pca(chip);
141 struct device *dev = pwmchip_parent(chip);
142 int err;
143
144 err = regmap_bulk_write(pca->regmap, reg, val, 4);
145 if (err)
146 dev_err(dev, "regmap_write to register 0x%x failed: %pe\n", reg, ERR_PTR(err));
147
148 return err;
149}
150
151static int pca9685_set_sleep_mode(struct pwm_chip *chip, bool enable)
152{
153 struct pca9685 *pca = to_pca(chip);
154 int err;
155
156 err = regmap_update_bits(pca->regmap, PCA9685_MODE1,
157 MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
158 if (err)
159 return err;
160
161 if (!enable) {
162 /* Wait 500us for the oscillator to be back up */
163 udelay(500);
164 }
165
166 return 0;
167}
168
169struct pca9685_waveform {
170 u8 onoff[4];
171 u8 prescale;
172};
173
174static int pca9685_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_waveform *wf, void *_wfhw)
175{
176 struct pca9685_waveform *wfhw = _wfhw;
177 struct pca9685 *pca = to_pca(chip);
178 unsigned int best_prescale;
179 u8 prescale;
180 unsigned int period_ns, duty;
181 int ret_tohw = 0;
182
183 if (!wf->period_length_ns) {
184 *wfhw = (typeof(*wfhw)){
185 .onoff = { 0, 0, 0, LED_FULL, },
186 .prescale = 0,
187 };
188
189 dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] -> [%hhx %hhx %hhx %hhx] PSC:%hhx\n",
190 pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
191 wfhw->onoff[0], wfhw->onoff[1], wfhw->onoff[2], wfhw->onoff[3], wfhw->prescale);
192
193 return 0;
194 }
195
196 if (wf->period_length_ns >= PCA9685_COUNTER_RANGE * PCA9685_QUANTUM_NS(255)) {
197 best_prescale = 255;
198 } else if (wf->period_length_ns < PCA9685_COUNTER_RANGE * PCA9685_QUANTUM_NS(3)) {
199 best_prescale = 3;
200 ret_tohw = 1;
201 } else {
202 best_prescale = (unsigned int)wf->period_length_ns / (PCA9685_COUNTER_RANGE * (NSEC_PER_SEC / PCA9685_OSC_CLOCK_HZ)) - 1;
203 }
204
205 guard(mutex)(&pca->lock);
206
207 if (!pca9685_prescaler_can_change(pca, pwm->hwpwm)) {
208 unsigned int current_prescale;
209 int ret;
210
211 ret = regmap_read(pca->regmap, PCA9685_PRESCALE, &current_prescale);
212 if (ret)
213 return ret;
214
215 if (current_prescale > best_prescale)
216 ret_tohw = 1;
217
218 prescale = current_prescale;
219 } else {
220 prescale = best_prescale;
221 }
222
223 period_ns = PCA9685_COUNTER_RANGE * PCA9685_QUANTUM_NS(prescale);
224
225 duty = (unsigned)min_t(u64, wf->duty_length_ns, period_ns) / PCA9685_QUANTUM_NS(prescale);
226
227 if (duty < PCA9685_COUNTER_RANGE) {
228 unsigned int on, off;
229
230 on = (unsigned)min_t(u64, wf->duty_offset_ns, period_ns) / PCA9685_QUANTUM_NS(prescale);
231 off = (on + duty) % PCA9685_COUNTER_RANGE;
232
233 /*
234 * With a zero duty cycle, it doesn't matter if period was
235 * rounded up
236 */
237 if (!duty)
238 ret_tohw = 0;
239
240 *wfhw = (typeof(*wfhw)){
241 .onoff = { on & 0xff, (on >> 8) & 0xf, off & 0xff, (off >> 8) & 0xf },
242 .prescale = prescale,
243 };
244 } else {
245 *wfhw = (typeof(*wfhw)){
246 .onoff = { 0, LED_FULL, 0, 0, },
247 .prescale = prescale,
248 };
249 }
250
251 dev_dbg(&chip->dev, "pwm#%u: %lld/%lld [+%lld] -> %s[%hhx %hhx %hhx %hhx] PSC:%hhx\n",
252 pwm->hwpwm, wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
253 ret_tohw ? "#" : "", wfhw->onoff[0], wfhw->onoff[1], wfhw->onoff[2], wfhw->onoff[3], wfhw->prescale);
254
255 return ret_tohw;
256}
257
258static int pca9685_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
259 const void *_wfhw, struct pwm_waveform *wf)
260{
261 const struct pca9685_waveform *wfhw = _wfhw;
262 struct pca9685 *pca = to_pca(chip);
263 unsigned int prescale;
264
265 if (wfhw->prescale)
266 prescale = wfhw->prescale;
267 else
268 scoped_guard(mutex, &pca->lock) {
269 int ret;
270
271 ret = regmap_read(pca->regmap, PCA9685_PRESCALE, &prescale);
272 if (ret)
273 return ret;
274 }
275
276 wf->period_length_ns = PCA9685_COUNTER_RANGE * PCA9685_QUANTUM_NS(prescale);
277
278 if (wfhw->onoff[3] & LED_FULL) {
279 wf->duty_length_ns = 0;
280 wf->duty_offset_ns = 0;
281 } else if (wfhw->onoff[1] & LED_FULL) {
282 wf->duty_length_ns = wf->period_length_ns;
283 wf->duty_offset_ns = 0;
284 } else {
285 unsigned int on = wfhw->onoff[0] | (wfhw->onoff[1] & 0xf) << 8;
286 unsigned int off = wfhw->onoff[2] | (wfhw->onoff[3] & 0xf) << 8;
287
288 wf->duty_length_ns = (off - on) % PCA9685_COUNTER_RANGE * PCA9685_QUANTUM_NS(prescale);
289 wf->duty_offset_ns = on * PCA9685_QUANTUM_NS(prescale);
290 }
291
292 dev_dbg(&chip->dev, "pwm#%u: [%hhx %hhx %hhx %hhx] PSC:%hhx -> %lld/%lld [+%lld]\n",
293 pwm->hwpwm,
294 wfhw->onoff[0], wfhw->onoff[1], wfhw->onoff[2], wfhw->onoff[3], wfhw->prescale,
295 wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns);
296
297 return 0;
298}
299
300static int pca9685_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *_wfhw)
301{
302 struct pca9685_waveform *wfhw = _wfhw;
303 struct pca9685 *pca = to_pca(chip);
304 unsigned int prescale;
305 int ret;
306
307 guard(mutex)(&pca->lock);
308
309 ret = regmap_bulk_read(pca->regmap, REG_ON_L(pwm->hwpwm), &wfhw->onoff, 4);
310 if (ret)
311 return ret;
312
313 ret = regmap_read(pca->regmap, PCA9685_PRESCALE, &prescale);
314 if (ret)
315 return ret;
316
317 wfhw->prescale = prescale;
318
319 return 0;
320}
321
322static int pca9685_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *_wfhw)
323{
324 const struct pca9685_waveform *wfhw = _wfhw;
325 struct pca9685 *pca = to_pca(chip);
326 unsigned int current_prescale;
327 int ret;
328
329 guard(mutex)(&pca->lock);
330
331 if (wfhw->prescale) {
332 ret = regmap_read(pca->regmap, PCA9685_PRESCALE, &current_prescale);
333 if (ret)
334 return ret;
335
336 if (current_prescale != wfhw->prescale) {
337 if (!pca9685_prescaler_can_change(pca, pwm->hwpwm))
338 return -EBUSY;
339
340 /* Put chip into sleep mode */
341 ret = pca9685_set_sleep_mode(chip, true);
342 if (ret)
343 return ret;
344
345 /* Change the chip-wide output frequency */
346 ret = regmap_write(pca->regmap, PCA9685_PRESCALE, wfhw->prescale);
347 if (ret)
348 return ret;
349
350 /* Wake the chip up */
351 ret = pca9685_set_sleep_mode(chip, false);
352 if (ret)
353 return ret;
354 }
355 }
356
357 return regmap_bulk_write(pca->regmap, REG_ON_L(pwm->hwpwm), &wfhw->onoff, 4);
358}
359
360static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
361{
362 struct pca9685 *pca = to_pca(chip);
363
364 if (pwm->hwpwm < PCA9685_MAXCHAN) {
365 /* PWMs - except the "all LEDs" channel - default to enabled */
366 mutex_lock(&pca->lock);
367 set_bit(pwm->hwpwm, pca->pwms_enabled);
368 mutex_unlock(&pca->lock);
369 }
370
371 pm_runtime_get_sync(pwmchip_parent(chip));
372
373 return 0;
374}
375
376static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
377{
378 struct pca9685 *pca = to_pca(chip);
379
380 mutex_lock(&pca->lock);
381 clear_bit(pwm->hwpwm, pca->pwms_enabled);
382 mutex_unlock(&pca->lock);
383
384 pm_runtime_put(pwmchip_parent(chip));
385}
386
387static const struct pwm_ops pca9685_pwm_ops = {
388 .sizeof_wfhw = sizeof(struct pca9685_waveform),
389 .round_waveform_tohw = pca9685_round_waveform_tohw,
390 .round_waveform_fromhw = pca9685_round_waveform_fromhw,
391 .read_waveform = pca9685_read_waveform,
392 .write_waveform = pca9685_write_waveform,
393 .request = pca9685_pwm_request,
394 .free = pca9685_pwm_free,
395};
396
397static bool pca9685_readable_reg(struct device *dev, unsigned int reg)
398{
399 /* The ALL_LED registers are readable but read as zero */
400 return reg <= REG_OFF_H(15) || reg >= PCA9685_PRESCALE;
401}
402
403static bool pca9685_writeable_reg(struct device *dev, unsigned int reg)
404{
405 return reg <= REG_OFF_H(15) || reg >= PCA9685_ALL_LED_ON_L;
406}
407
408static bool pca9685_volatile_reg(struct device *dev, unsigned int reg)
409{
410 /*
411 * Writing to an ALL_LED register affects all LEDi registers, so they
412 * are not cachable. :-\
413 */
414 return reg < PCA9685_PRESCALE;
415}
416
417static const struct regmap_config pca9685_regmap_i2c_config = {
418 .reg_bits = 8,
419 .val_bits = 8,
420
421 .readable_reg = pca9685_readable_reg,
422 .writeable_reg = pca9685_writeable_reg,
423 .volatile_reg = pca9685_volatile_reg,
424
425 .max_register = PCA9685_NUMREGS,
426 .cache_type = REGCACHE_MAPLE,
427};
428
429static int pca9685_pwm_probe(struct i2c_client *client)
430{
431 struct pwm_chip *chip;
432 struct pca9685 *pca;
433 unsigned int reg;
434 int ret;
435
436 /* Add an extra channel for ALL_LED */
437 chip = devm_pwmchip_alloc(&client->dev, PCA9685_MAXCHAN + 1, sizeof(*pca));
438 if (IS_ERR(chip))
439 return PTR_ERR(chip);
440 pca = to_pca(chip);
441
442 pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
443 if (IS_ERR(pca->regmap)) {
444 ret = PTR_ERR(pca->regmap);
445 dev_err(&client->dev, "Failed to initialize register map: %d\n",
446 ret);
447 return ret;
448 }
449
450 i2c_set_clientdata(client, chip);
451
452 mutex_init(&pca->lock);
453
454 /* clear MODE2_OCH */
455 reg = 0;
456
457 if (device_property_read_bool(&client->dev, "invert"))
458 reg |= MODE2_INVRT;
459 else
460 reg &= ~MODE2_INVRT;
461
462 if (device_property_read_bool(&client->dev, "open-drain"))
463 reg &= ~MODE2_OUTDRV;
464 else
465 reg |= MODE2_OUTDRV;
466
467 ret = pca9685_write_reg(chip, PCA9685_MODE2, reg);
468 if (ret)
469 return ret;
470
471 /*
472 * Disable all LED ALLCALL and SUBx addresses to avoid bus collisions,
473 * enable Auto-Increment.
474 */
475 pca9685_read_reg(chip, PCA9685_MODE1, &reg);
476 reg &= ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3);
477 reg |= MODE1_AI;
478 pca9685_write_reg(chip, PCA9685_MODE1, reg);
479
480 /* Reset OFF/ON registers to POR default */
481 ret = pca9685_write_4reg(chip, PCA9685_ALL_LED_ON_L, (u8[]){ 0, LED_FULL, 0, LED_FULL });
482 if (ret < 0)
483 return dev_err_probe(&client->dev, ret, "Failed to reset ON/OFF registers\n");
484
485 chip->ops = &pca9685_pwm_ops;
486
487 ret = pwmchip_add(chip);
488 if (ret < 0)
489 return ret;
490
491 pm_runtime_enable(&client->dev);
492
493 if (pm_runtime_enabled(&client->dev)) {
494 /*
495 * Although the chip comes out of power-up in the sleep state,
496 * we force it to sleep in case it was woken up before
497 */
498 pca9685_set_sleep_mode(chip, true);
499 pm_runtime_set_suspended(&client->dev);
500 } else {
501 /* Wake the chip up if runtime PM is disabled */
502 pca9685_set_sleep_mode(chip, false);
503 }
504
505 return 0;
506}
507
508static void pca9685_pwm_remove(struct i2c_client *client)
509{
510 struct pwm_chip *chip = i2c_get_clientdata(client);
511
512 pwmchip_remove(chip);
513
514 if (!pm_runtime_enabled(&client->dev)) {
515 /* Put chip in sleep state if runtime PM is disabled */
516 pca9685_set_sleep_mode(chip, true);
517 }
518
519 pm_runtime_disable(&client->dev);
520}
521
522static int __maybe_unused pca9685_pwm_runtime_suspend(struct device *dev)
523{
524 struct i2c_client *client = to_i2c_client(dev);
525 struct pwm_chip *chip = i2c_get_clientdata(client);
526
527 pca9685_set_sleep_mode(chip, true);
528 return 0;
529}
530
531static int __maybe_unused pca9685_pwm_runtime_resume(struct device *dev)
532{
533 struct i2c_client *client = to_i2c_client(dev);
534 struct pwm_chip *chip = i2c_get_clientdata(client);
535
536 pca9685_set_sleep_mode(chip, false);
537 return 0;
538}
539
540static const struct i2c_device_id pca9685_id[] = {
541 { .name = "pca9685" },
542 { /* sentinel */ }
543};
544MODULE_DEVICE_TABLE(i2c, pca9685_id);
545
546static const struct acpi_device_id pca9685_acpi_ids[] = {
547 { .id = "INT3492" },
548 { /* sentinel */ }
549};
550MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
551
552static const struct of_device_id pca9685_dt_ids[] = {
553 { .compatible = "nxp,pca9685-pwm" },
554 { /* sentinel */ }
555};
556MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
557
558static const struct dev_pm_ops pca9685_pwm_pm = {
559 SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
560 pca9685_pwm_runtime_resume, NULL)
561};
562
563static struct i2c_driver pca9685_i2c_driver = {
564 .driver = {
565 .name = "pca9685-pwm",
566 .acpi_match_table = pca9685_acpi_ids,
567 .of_match_table = pca9685_dt_ids,
568 .pm = &pca9685_pwm_pm,
569 },
570 .probe = pca9685_pwm_probe,
571 .remove = pca9685_pwm_remove,
572 .id_table = pca9685_id,
573};
574
575module_i2c_driver(pca9685_i2c_driver);
576
577MODULE_AUTHOR("Steffen Trumtrar <[email protected]>");
578MODULE_DESCRIPTION("PWM driver for PCA9685");
579MODULE_LICENSE("GPL");