1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Generic pwmlib implementation |
4 | * |
5 | * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de> |
6 | * Copyright (C) 2011-2012 Avionic Design GmbH |
7 | */ |
8 | |
9 | #include <linux/acpi.h> |
10 | #include <linux/module.h> |
11 | #include <linux/idr.h> |
12 | #include <linux/of.h> |
13 | #include <linux/pwm.h> |
14 | #include <linux/list.h> |
15 | #include <linux/mutex.h> |
16 | #include <linux/err.h> |
17 | #include <linux/slab.h> |
18 | #include <linux/device.h> |
19 | #include <linux/debugfs.h> |
20 | #include <linux/seq_file.h> |
21 | |
22 | #include <dt-bindings/pwm/pwm.h> |
23 | |
24 | #define CREATE_TRACE_POINTS |
25 | #include <trace/events/pwm.h> |
26 | |
27 | /* protects access to pwm_chips */ |
28 | static DEFINE_MUTEX(pwm_lock); |
29 | |
30 | static DEFINE_IDR(pwm_chips); |
31 | |
32 | static void pwm_apply_debug(struct pwm_device *pwm, |
33 | const struct pwm_state *state) |
34 | { |
35 | struct pwm_state *last = &pwm->last; |
36 | struct pwm_chip *chip = pwm->chip; |
37 | struct pwm_state s1 = { 0 }, s2 = { 0 }; |
38 | int err; |
39 | |
40 | if (!IS_ENABLED(CONFIG_PWM_DEBUG)) |
41 | return; |
42 | |
43 | /* No reasonable diagnosis possible without .get_state() */ |
44 | if (!chip->ops->get_state) |
45 | return; |
46 | |
47 | /* |
48 | * *state was just applied. Read out the hardware state and do some |
49 | * checks. |
50 | */ |
51 | |
52 | err = chip->ops->get_state(chip, pwm, &s1); |
53 | trace_pwm_get(pwm, state: &s1, err); |
54 | if (err) |
55 | /* If that failed there isn't much to debug */ |
56 | return; |
57 | |
58 | /* |
59 | * The lowlevel driver either ignored .polarity (which is a bug) or as |
60 | * best effort inverted .polarity and fixed .duty_cycle respectively. |
61 | * Undo this inversion and fixup for further tests. |
62 | */ |
63 | if (s1.enabled && s1.polarity != state->polarity) { |
64 | s2.polarity = state->polarity; |
65 | s2.duty_cycle = s1.period - s1.duty_cycle; |
66 | s2.period = s1.period; |
67 | s2.enabled = s1.enabled; |
68 | } else { |
69 | s2 = s1; |
70 | } |
71 | |
72 | if (s2.polarity != state->polarity && |
73 | state->duty_cycle < state->period) |
74 | dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n" ); |
75 | |
76 | if (state->enabled && |
77 | last->polarity == state->polarity && |
78 | last->period > s2.period && |
79 | last->period <= state->period) |
80 | dev_warn(pwmchip_parent(chip), |
81 | ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n" , |
82 | state->period, s2.period, last->period); |
83 | |
84 | if (state->enabled && state->period < s2.period) |
85 | dev_warn(pwmchip_parent(chip), |
86 | ".apply is supposed to round down period (requested: %llu, applied: %llu)\n" , |
87 | state->period, s2.period); |
88 | |
89 | if (state->enabled && |
90 | last->polarity == state->polarity && |
91 | last->period == s2.period && |
92 | last->duty_cycle > s2.duty_cycle && |
93 | last->duty_cycle <= state->duty_cycle) |
94 | dev_warn(pwmchip_parent(chip), |
95 | ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n" , |
96 | state->duty_cycle, state->period, |
97 | s2.duty_cycle, s2.period, |
98 | last->duty_cycle, last->period); |
99 | |
100 | if (state->enabled && state->duty_cycle < s2.duty_cycle) |
101 | dev_warn(pwmchip_parent(chip), |
102 | ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n" , |
103 | state->duty_cycle, state->period, |
104 | s2.duty_cycle, s2.period); |
105 | |
106 | if (!state->enabled && s2.enabled && s2.duty_cycle > 0) |
107 | dev_warn(pwmchip_parent(chip), |
108 | "requested disabled, but yielded enabled with duty > 0\n" ); |
109 | |
110 | /* reapply the state that the driver reported being configured. */ |
111 | err = chip->ops->apply(chip, pwm, &s1); |
112 | trace_pwm_apply(pwm, state: &s1, err); |
113 | if (err) { |
114 | *last = s1; |
115 | dev_err(pwmchip_parent(chip), "failed to reapply current setting\n" ); |
116 | return; |
117 | } |
118 | |
119 | *last = (struct pwm_state){ 0 }; |
120 | err = chip->ops->get_state(chip, pwm, last); |
121 | trace_pwm_get(pwm, last, err); |
122 | if (err) |
123 | return; |
124 | |
125 | /* reapplication of the current state should give an exact match */ |
126 | if (s1.enabled != last->enabled || |
127 | s1.polarity != last->polarity || |
128 | (s1.enabled && s1.period != last->period) || |
129 | (s1.enabled && s1.duty_cycle != last->duty_cycle)) { |
130 | dev_err(pwmchip_parent(chip), |
131 | ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n" , |
132 | s1.enabled, s1.polarity, s1.duty_cycle, s1.period, |
133 | last->enabled, last->polarity, last->duty_cycle, |
134 | last->period); |
135 | } |
136 | } |
137 | |
138 | /** |
139 | * __pwm_apply() - atomically apply a new state to a PWM device |
140 | * @pwm: PWM device |
141 | * @state: new state to apply |
142 | */ |
143 | static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state) |
144 | { |
145 | struct pwm_chip *chip; |
146 | int err; |
147 | |
148 | if (!pwm || !state || !state->period || |
149 | state->duty_cycle > state->period) |
150 | return -EINVAL; |
151 | |
152 | chip = pwm->chip; |
153 | |
154 | if (state->period == pwm->state.period && |
155 | state->duty_cycle == pwm->state.duty_cycle && |
156 | state->polarity == pwm->state.polarity && |
157 | state->enabled == pwm->state.enabled && |
158 | state->usage_power == pwm->state.usage_power) |
159 | return 0; |
160 | |
161 | err = chip->ops->apply(chip, pwm, state); |
162 | trace_pwm_apply(pwm, state, err); |
163 | if (err) |
164 | return err; |
165 | |
166 | pwm->state = *state; |
167 | |
168 | /* |
169 | * only do this after pwm->state was applied as some |
170 | * implementations of .get_state depend on this |
171 | */ |
172 | pwm_apply_debug(pwm, state); |
173 | |
174 | return 0; |
175 | } |
176 | |
177 | /** |
178 | * pwm_apply_might_sleep() - atomically apply a new state to a PWM device |
179 | * Cannot be used in atomic context. |
180 | * @pwm: PWM device |
181 | * @state: new state to apply |
182 | */ |
183 | int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state) |
184 | { |
185 | int err; |
186 | |
187 | /* |
188 | * Some lowlevel driver's implementations of .apply() make use of |
189 | * mutexes, also with some drivers only returning when the new |
190 | * configuration is active calling pwm_apply_might_sleep() from atomic context |
191 | * is a bad idea. So make it explicit that calling this function might |
192 | * sleep. |
193 | */ |
194 | might_sleep(); |
195 | |
196 | if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) { |
197 | /* |
198 | * Catch any drivers that have been marked as atomic but |
199 | * that will sleep anyway. |
200 | */ |
201 | non_block_start(); |
202 | err = __pwm_apply(pwm, state); |
203 | non_block_end(); |
204 | } else { |
205 | err = __pwm_apply(pwm, state); |
206 | } |
207 | |
208 | return err; |
209 | } |
210 | EXPORT_SYMBOL_GPL(pwm_apply_might_sleep); |
211 | |
212 | /** |
213 | * pwm_apply_atomic() - apply a new state to a PWM device from atomic context |
214 | * Not all PWM devices support this function, check with pwm_might_sleep(). |
215 | * @pwm: PWM device |
216 | * @state: new state to apply |
217 | */ |
218 | int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state) |
219 | { |
220 | WARN_ONCE(!pwm->chip->atomic, |
221 | "sleeping PWM driver used in atomic context\n" ); |
222 | |
223 | return __pwm_apply(pwm, state); |
224 | } |
225 | EXPORT_SYMBOL_GPL(pwm_apply_atomic); |
226 | |
227 | /** |
228 | * pwm_adjust_config() - adjust the current PWM config to the PWM arguments |
229 | * @pwm: PWM device |
230 | * |
231 | * This function will adjust the PWM config to the PWM arguments provided |
232 | * by the DT or PWM lookup table. This is particularly useful to adapt |
233 | * the bootloader config to the Linux one. |
234 | */ |
235 | int pwm_adjust_config(struct pwm_device *pwm) |
236 | { |
237 | struct pwm_state state; |
238 | struct pwm_args pargs; |
239 | |
240 | pwm_get_args(pwm, args: &pargs); |
241 | pwm_get_state(pwm, state: &state); |
242 | |
243 | /* |
244 | * If the current period is zero it means that either the PWM driver |
245 | * does not support initial state retrieval or the PWM has not yet |
246 | * been configured. |
247 | * |
248 | * In either case, we setup the new period and polarity, and assign a |
249 | * duty cycle of 0. |
250 | */ |
251 | if (!state.period) { |
252 | state.duty_cycle = 0; |
253 | state.period = pargs.period; |
254 | state.polarity = pargs.polarity; |
255 | |
256 | return pwm_apply_might_sleep(pwm, &state); |
257 | } |
258 | |
259 | /* |
260 | * Adjust the PWM duty cycle/period based on the period value provided |
261 | * in PWM args. |
262 | */ |
263 | if (pargs.period != state.period) { |
264 | u64 dutycycle = (u64)state.duty_cycle * pargs.period; |
265 | |
266 | do_div(dutycycle, state.period); |
267 | state.duty_cycle = dutycycle; |
268 | state.period = pargs.period; |
269 | } |
270 | |
271 | /* |
272 | * If the polarity changed, we should also change the duty cycle. |
273 | */ |
274 | if (pargs.polarity != state.polarity) { |
275 | state.polarity = pargs.polarity; |
276 | state.duty_cycle = state.period - state.duty_cycle; |
277 | } |
278 | |
279 | return pwm_apply_might_sleep(pwm, &state); |
280 | } |
281 | EXPORT_SYMBOL_GPL(pwm_adjust_config); |
282 | |
283 | /** |
284 | * pwm_capture() - capture and report a PWM signal |
285 | * @pwm: PWM device |
286 | * @result: structure to fill with capture result |
287 | * @timeout: time to wait, in milliseconds, before giving up on capture |
288 | * |
289 | * Returns: 0 on success or a negative error code on failure. |
290 | */ |
291 | int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, |
292 | unsigned long timeout) |
293 | { |
294 | int err; |
295 | |
296 | if (!pwm || !pwm->chip->ops) |
297 | return -EINVAL; |
298 | |
299 | if (!pwm->chip->ops->capture) |
300 | return -ENOSYS; |
301 | |
302 | mutex_lock(&pwm_lock); |
303 | err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout); |
304 | mutex_unlock(lock: &pwm_lock); |
305 | |
306 | return err; |
307 | } |
308 | EXPORT_SYMBOL_GPL(pwm_capture); |
309 | |
310 | static struct pwm_chip *pwmchip_find_by_name(const char *name) |
311 | { |
312 | struct pwm_chip *chip; |
313 | unsigned long id, tmp; |
314 | |
315 | if (!name) |
316 | return NULL; |
317 | |
318 | mutex_lock(&pwm_lock); |
319 | |
320 | idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) { |
321 | const char *chip_name = dev_name(dev: pwmchip_parent(chip)); |
322 | |
323 | if (chip_name && strcmp(chip_name, name) == 0) { |
324 | mutex_unlock(lock: &pwm_lock); |
325 | return chip; |
326 | } |
327 | } |
328 | |
329 | mutex_unlock(lock: &pwm_lock); |
330 | |
331 | return NULL; |
332 | } |
333 | |
334 | static int pwm_device_request(struct pwm_device *pwm, const char *label) |
335 | { |
336 | int err; |
337 | struct pwm_chip *chip = pwm->chip; |
338 | const struct pwm_ops *ops = chip->ops; |
339 | |
340 | if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
341 | return -EBUSY; |
342 | |
343 | if (!try_module_get(module: chip->owner)) |
344 | return -ENODEV; |
345 | |
346 | if (ops->request) { |
347 | err = ops->request(chip, pwm); |
348 | if (err) { |
349 | module_put(module: chip->owner); |
350 | return err; |
351 | } |
352 | } |
353 | |
354 | if (ops->get_state) { |
355 | /* |
356 | * Zero-initialize state because most drivers are unaware of |
357 | * .usage_power. The other members of state are supposed to be |
358 | * set by lowlevel drivers. We still initialize the whole |
359 | * structure for simplicity even though this might paper over |
360 | * faulty implementations of .get_state(). |
361 | */ |
362 | struct pwm_state state = { 0, }; |
363 | |
364 | err = ops->get_state(chip, pwm, &state); |
365 | trace_pwm_get(pwm, state: &state, err); |
366 | |
367 | if (!err) |
368 | pwm->state = state; |
369 | |
370 | if (IS_ENABLED(CONFIG_PWM_DEBUG)) |
371 | pwm->last = pwm->state; |
372 | } |
373 | |
374 | set_bit(nr: PWMF_REQUESTED, addr: &pwm->flags); |
375 | pwm->label = label; |
376 | |
377 | return 0; |
378 | } |
379 | |
380 | /** |
381 | * pwm_request_from_chip() - request a PWM device relative to a PWM chip |
382 | * @chip: PWM chip |
383 | * @index: per-chip index of the PWM to request |
384 | * @label: a literal description string of this PWM |
385 | * |
386 | * Returns: A pointer to the PWM device at the given index of the given PWM |
387 | * chip. A negative error code is returned if the index is not valid for the |
388 | * specified PWM chip or if the PWM device cannot be requested. |
389 | */ |
390 | struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
391 | unsigned int index, |
392 | const char *label) |
393 | { |
394 | struct pwm_device *pwm; |
395 | int err; |
396 | |
397 | if (!chip || index >= chip->npwm) |
398 | return ERR_PTR(error: -EINVAL); |
399 | |
400 | mutex_lock(&pwm_lock); |
401 | pwm = &chip->pwms[index]; |
402 | |
403 | err = pwm_device_request(pwm, label); |
404 | if (err < 0) |
405 | pwm = ERR_PTR(error: err); |
406 | |
407 | mutex_unlock(lock: &pwm_lock); |
408 | return pwm; |
409 | } |
410 | EXPORT_SYMBOL_GPL(pwm_request_from_chip); |
411 | |
412 | |
413 | struct pwm_device * |
414 | of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args) |
415 | { |
416 | struct pwm_device *pwm; |
417 | |
418 | /* period in the second cell and flags in the third cell are optional */ |
419 | if (args->args_count < 1) |
420 | return ERR_PTR(error: -EINVAL); |
421 | |
422 | pwm = pwm_request_from_chip(chip, args->args[0], NULL); |
423 | if (IS_ERR(ptr: pwm)) |
424 | return pwm; |
425 | |
426 | if (args->args_count > 1) |
427 | pwm->args.period = args->args[1]; |
428 | |
429 | pwm->args.polarity = PWM_POLARITY_NORMAL; |
430 | if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED) |
431 | pwm->args.polarity = PWM_POLARITY_INVERSED; |
432 | |
433 | return pwm; |
434 | } |
435 | EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); |
436 | |
437 | struct pwm_device * |
438 | of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args) |
439 | { |
440 | struct pwm_device *pwm; |
441 | |
442 | pwm = pwm_request_from_chip(chip, 0, NULL); |
443 | if (IS_ERR(ptr: pwm)) |
444 | return pwm; |
445 | |
446 | if (args->args_count > 0) |
447 | pwm->args.period = args->args[0]; |
448 | |
449 | pwm->args.polarity = PWM_POLARITY_NORMAL; |
450 | if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED) |
451 | pwm->args.polarity = PWM_POLARITY_INVERSED; |
452 | |
453 | return pwm; |
454 | } |
455 | EXPORT_SYMBOL_GPL(of_pwm_single_xlate); |
456 | |
457 | #define PWMCHIP_ALIGN ARCH_DMA_MINALIGN |
458 | |
459 | static void *pwmchip_priv(struct pwm_chip *chip) |
460 | { |
461 | return (void *)chip + ALIGN(sizeof(*chip), PWMCHIP_ALIGN); |
462 | } |
463 | |
464 | /* This is the counterpart to pwmchip_alloc() */ |
465 | void pwmchip_put(struct pwm_chip *chip) |
466 | { |
467 | kfree(objp: chip); |
468 | } |
469 | EXPORT_SYMBOL_GPL(pwmchip_put); |
470 | |
471 | struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) |
472 | { |
473 | struct pwm_chip *chip; |
474 | size_t alloc_size; |
475 | |
476 | alloc_size = size_add(ALIGN(sizeof(*chip), PWMCHIP_ALIGN), addend2: sizeof_priv); |
477 | |
478 | chip = kzalloc(size: alloc_size, GFP_KERNEL); |
479 | if (!chip) |
480 | return ERR_PTR(error: -ENOMEM); |
481 | |
482 | chip->dev = parent; |
483 | chip->npwm = npwm; |
484 | |
485 | pwmchip_set_drvdata(chip, data: pwmchip_priv(chip)); |
486 | |
487 | return chip; |
488 | } |
489 | EXPORT_SYMBOL_GPL(pwmchip_alloc); |
490 | |
491 | static void devm_pwmchip_put(void *data) |
492 | { |
493 | struct pwm_chip *chip = data; |
494 | |
495 | pwmchip_put(chip); |
496 | } |
497 | |
498 | struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) |
499 | { |
500 | struct pwm_chip *chip; |
501 | int ret; |
502 | |
503 | chip = pwmchip_alloc(parent, npwm, sizeof_priv); |
504 | if (IS_ERR(ptr: chip)) |
505 | return chip; |
506 | |
507 | ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip); |
508 | if (ret) |
509 | return ERR_PTR(error: ret); |
510 | |
511 | return chip; |
512 | } |
513 | EXPORT_SYMBOL_GPL(devm_pwmchip_alloc); |
514 | |
515 | static void of_pwmchip_add(struct pwm_chip *chip) |
516 | { |
517 | if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node) |
518 | return; |
519 | |
520 | if (!chip->of_xlate) |
521 | chip->of_xlate = of_pwm_xlate_with_flags; |
522 | |
523 | of_node_get(node: pwmchip_parent(chip)->of_node); |
524 | } |
525 | |
526 | static void of_pwmchip_remove(struct pwm_chip *chip) |
527 | { |
528 | if (pwmchip_parent(chip)) |
529 | of_node_put(node: pwmchip_parent(chip)->of_node); |
530 | } |
531 | |
532 | static bool pwm_ops_check(const struct pwm_chip *chip) |
533 | { |
534 | const struct pwm_ops *ops = chip->ops; |
535 | |
536 | if (!ops->apply) |
537 | return false; |
538 | |
539 | if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state) |
540 | dev_warn(pwmchip_parent(chip), |
541 | "Please implement the .get_state() callback\n" ); |
542 | |
543 | return true; |
544 | } |
545 | |
546 | /** |
547 | * __pwmchip_add() - register a new PWM chip |
548 | * @chip: the PWM chip to add |
549 | * @owner: reference to the module providing the chip. |
550 | * |
551 | * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the |
552 | * pwmchip_add wrapper to do this right. |
553 | * |
554 | * Returns: 0 on success or a negative error code on failure. |
555 | */ |
556 | int __pwmchip_add(struct pwm_chip *chip, struct module *owner) |
557 | { |
558 | unsigned int i; |
559 | int ret; |
560 | |
561 | if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm) |
562 | return -EINVAL; |
563 | |
564 | if (!pwm_ops_check(chip)) |
565 | return -EINVAL; |
566 | |
567 | chip->owner = owner; |
568 | |
569 | chip->pwms = kcalloc(n: chip->npwm, size: sizeof(*chip->pwms), GFP_KERNEL); |
570 | if (!chip->pwms) |
571 | return -ENOMEM; |
572 | |
573 | mutex_lock(&pwm_lock); |
574 | |
575 | ret = idr_alloc(&pwm_chips, ptr: chip, start: 0, end: 0, GFP_KERNEL); |
576 | if (ret < 0) { |
577 | mutex_unlock(lock: &pwm_lock); |
578 | kfree(objp: chip->pwms); |
579 | return ret; |
580 | } |
581 | |
582 | chip->id = ret; |
583 | |
584 | for (i = 0; i < chip->npwm; i++) { |
585 | struct pwm_device *pwm = &chip->pwms[i]; |
586 | |
587 | pwm->chip = chip; |
588 | pwm->hwpwm = i; |
589 | } |
590 | |
591 | mutex_unlock(lock: &pwm_lock); |
592 | |
593 | if (IS_ENABLED(CONFIG_OF)) |
594 | of_pwmchip_add(chip); |
595 | |
596 | pwmchip_sysfs_export(chip); |
597 | |
598 | return 0; |
599 | } |
600 | EXPORT_SYMBOL_GPL(__pwmchip_add); |
601 | |
602 | /** |
603 | * pwmchip_remove() - remove a PWM chip |
604 | * @chip: the PWM chip to remove |
605 | * |
606 | * Removes a PWM chip. |
607 | */ |
608 | void pwmchip_remove(struct pwm_chip *chip) |
609 | { |
610 | pwmchip_sysfs_unexport(chip); |
611 | |
612 | if (IS_ENABLED(CONFIG_OF)) |
613 | of_pwmchip_remove(chip); |
614 | |
615 | mutex_lock(&pwm_lock); |
616 | |
617 | idr_remove(&pwm_chips, id: chip->id); |
618 | |
619 | mutex_unlock(lock: &pwm_lock); |
620 | |
621 | kfree(objp: chip->pwms); |
622 | } |
623 | EXPORT_SYMBOL_GPL(pwmchip_remove); |
624 | |
625 | static void devm_pwmchip_remove(void *data) |
626 | { |
627 | struct pwm_chip *chip = data; |
628 | |
629 | pwmchip_remove(chip); |
630 | } |
631 | |
632 | int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner) |
633 | { |
634 | int ret; |
635 | |
636 | ret = __pwmchip_add(chip, owner); |
637 | if (ret) |
638 | return ret; |
639 | |
640 | return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip); |
641 | } |
642 | EXPORT_SYMBOL_GPL(__devm_pwmchip_add); |
643 | |
644 | static struct device_link *pwm_device_link_add(struct device *dev, |
645 | struct pwm_device *pwm) |
646 | { |
647 | struct device_link *dl; |
648 | |
649 | if (!dev) { |
650 | /* |
651 | * No device for the PWM consumer has been provided. It may |
652 | * impact the PM sequence ordering: the PWM supplier may get |
653 | * suspended before the consumer. |
654 | */ |
655 | dev_warn(pwmchip_parent(pwm->chip), |
656 | "No consumer device specified to create a link to\n" ); |
657 | return NULL; |
658 | } |
659 | |
660 | dl = device_link_add(consumer: dev, supplier: pwmchip_parent(chip: pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER); |
661 | if (!dl) { |
662 | dev_err(dev, "failed to create device link to %s\n" , |
663 | dev_name(pwmchip_parent(pwm->chip))); |
664 | return ERR_PTR(error: -EINVAL); |
665 | } |
666 | |
667 | return dl; |
668 | } |
669 | |
670 | static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode) |
671 | { |
672 | struct pwm_chip *chip; |
673 | unsigned long id, tmp; |
674 | |
675 | mutex_lock(&pwm_lock); |
676 | |
677 | idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) |
678 | if (pwmchip_parent(chip) && device_match_fwnode(dev: pwmchip_parent(chip), fwnode)) { |
679 | mutex_unlock(lock: &pwm_lock); |
680 | return chip; |
681 | } |
682 | |
683 | mutex_unlock(lock: &pwm_lock); |
684 | |
685 | return ERR_PTR(error: -EPROBE_DEFER); |
686 | } |
687 | |
688 | /** |
689 | * of_pwm_get() - request a PWM via the PWM framework |
690 | * @dev: device for PWM consumer |
691 | * @np: device node to get the PWM from |
692 | * @con_id: consumer name |
693 | * |
694 | * Returns the PWM device parsed from the phandle and index specified in the |
695 | * "pwms" property of a device tree node or a negative error-code on failure. |
696 | * Values parsed from the device tree are stored in the returned PWM device |
697 | * object. |
698 | * |
699 | * If con_id is NULL, the first PWM device listed in the "pwms" property will |
700 | * be requested. Otherwise the "pwm-names" property is used to do a reverse |
701 | * lookup of the PWM index. This also means that the "pwm-names" property |
702 | * becomes mandatory for devices that look up the PWM device via the con_id |
703 | * parameter. |
704 | * |
705 | * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
706 | * error code on failure. |
707 | */ |
708 | static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np, |
709 | const char *con_id) |
710 | { |
711 | struct pwm_device *pwm = NULL; |
712 | struct of_phandle_args args; |
713 | struct device_link *dl; |
714 | struct pwm_chip *chip; |
715 | int index = 0; |
716 | int err; |
717 | |
718 | if (con_id) { |
719 | index = of_property_match_string(np, propname: "pwm-names" , string: con_id); |
720 | if (index < 0) |
721 | return ERR_PTR(error: index); |
722 | } |
723 | |
724 | err = of_parse_phandle_with_args(np, list_name: "pwms" , cells_name: "#pwm-cells" , index, |
725 | out_args: &args); |
726 | if (err) { |
727 | pr_err("%s(): can't parse \"pwms\" property\n" , __func__); |
728 | return ERR_PTR(error: err); |
729 | } |
730 | |
731 | chip = fwnode_to_pwmchip(of_fwnode_handle(args.np)); |
732 | if (IS_ERR(ptr: chip)) { |
733 | if (PTR_ERR(ptr: chip) != -EPROBE_DEFER) |
734 | pr_err("%s(): PWM chip not found\n" , __func__); |
735 | |
736 | pwm = ERR_CAST(ptr: chip); |
737 | goto put; |
738 | } |
739 | |
740 | pwm = chip->of_xlate(chip, &args); |
741 | if (IS_ERR(ptr: pwm)) |
742 | goto put; |
743 | |
744 | dl = pwm_device_link_add(dev, pwm); |
745 | if (IS_ERR(ptr: dl)) { |
746 | /* of_xlate ended up calling pwm_request_from_chip() */ |
747 | pwm_put(pwm); |
748 | pwm = ERR_CAST(ptr: dl); |
749 | goto put; |
750 | } |
751 | |
752 | /* |
753 | * If a consumer name was not given, try to look it up from the |
754 | * "pwm-names" property if it exists. Otherwise use the name of |
755 | * the user device node. |
756 | */ |
757 | if (!con_id) { |
758 | err = of_property_read_string_index(np, propname: "pwm-names" , index, |
759 | output: &con_id); |
760 | if (err < 0) |
761 | con_id = np->name; |
762 | } |
763 | |
764 | pwm->label = con_id; |
765 | |
766 | put: |
767 | of_node_put(node: args.np); |
768 | |
769 | return pwm; |
770 | } |
771 | |
772 | /** |
773 | * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI |
774 | * @fwnode: firmware node to get the "pwms" property from |
775 | * |
776 | * Returns the PWM device parsed from the fwnode and index specified in the |
777 | * "pwms" property or a negative error-code on failure. |
778 | * Values parsed from the device tree are stored in the returned PWM device |
779 | * object. |
780 | * |
781 | * This is analogous to of_pwm_get() except con_id is not yet supported. |
782 | * ACPI entries must look like |
783 | * Package () {"pwms", Package () |
784 | * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}} |
785 | * |
786 | * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
787 | * error code on failure. |
788 | */ |
789 | static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode) |
790 | { |
791 | struct pwm_device *pwm; |
792 | struct fwnode_reference_args args; |
793 | struct pwm_chip *chip; |
794 | int ret; |
795 | |
796 | memset(&args, 0, sizeof(args)); |
797 | |
798 | ret = __acpi_node_get_property_reference(fwnode, name: "pwms" , index: 0, num_args: 3, args: &args); |
799 | if (ret < 0) |
800 | return ERR_PTR(error: ret); |
801 | |
802 | if (args.nargs < 2) |
803 | return ERR_PTR(error: -EPROTO); |
804 | |
805 | chip = fwnode_to_pwmchip(fwnode: args.fwnode); |
806 | if (IS_ERR(ptr: chip)) |
807 | return ERR_CAST(ptr: chip); |
808 | |
809 | pwm = pwm_request_from_chip(chip, args.args[0], NULL); |
810 | if (IS_ERR(ptr: pwm)) |
811 | return pwm; |
812 | |
813 | pwm->args.period = args.args[1]; |
814 | pwm->args.polarity = PWM_POLARITY_NORMAL; |
815 | |
816 | if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED) |
817 | pwm->args.polarity = PWM_POLARITY_INVERSED; |
818 | |
819 | return pwm; |
820 | } |
821 | |
822 | static DEFINE_MUTEX(pwm_lookup_lock); |
823 | static LIST_HEAD(pwm_lookup_list); |
824 | |
825 | /** |
826 | * pwm_add_table() - register PWM device consumers |
827 | * @table: array of consumers to register |
828 | * @num: number of consumers in table |
829 | */ |
830 | void pwm_add_table(struct pwm_lookup *table, size_t num) |
831 | { |
832 | mutex_lock(&pwm_lookup_lock); |
833 | |
834 | while (num--) { |
835 | list_add_tail(new: &table->list, head: &pwm_lookup_list); |
836 | table++; |
837 | } |
838 | |
839 | mutex_unlock(lock: &pwm_lookup_lock); |
840 | } |
841 | |
842 | /** |
843 | * pwm_remove_table() - unregister PWM device consumers |
844 | * @table: array of consumers to unregister |
845 | * @num: number of consumers in table |
846 | */ |
847 | void pwm_remove_table(struct pwm_lookup *table, size_t num) |
848 | { |
849 | mutex_lock(&pwm_lookup_lock); |
850 | |
851 | while (num--) { |
852 | list_del(entry: &table->list); |
853 | table++; |
854 | } |
855 | |
856 | mutex_unlock(lock: &pwm_lookup_lock); |
857 | } |
858 | |
859 | /** |
860 | * pwm_get() - look up and request a PWM device |
861 | * @dev: device for PWM consumer |
862 | * @con_id: consumer name |
863 | * |
864 | * Lookup is first attempted using DT. If the device was not instantiated from |
865 | * a device tree, a PWM chip and a relative index is looked up via a table |
866 | * supplied by board setup code (see pwm_add_table()). |
867 | * |
868 | * Once a PWM chip has been found the specified PWM device will be requested |
869 | * and is ready to be used. |
870 | * |
871 | * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
872 | * error code on failure. |
873 | */ |
874 | struct pwm_device *pwm_get(struct device *dev, const char *con_id) |
875 | { |
876 | const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL; |
877 | const char *dev_id = dev ? dev_name(dev) : NULL; |
878 | struct pwm_device *pwm; |
879 | struct pwm_chip *chip; |
880 | struct device_link *dl; |
881 | unsigned int best = 0; |
882 | struct pwm_lookup *p, *chosen = NULL; |
883 | unsigned int match; |
884 | int err; |
885 | |
886 | /* look up via DT first */ |
887 | if (is_of_node(fwnode)) |
888 | return of_pwm_get(dev, to_of_node(fwnode), con_id); |
889 | |
890 | /* then lookup via ACPI */ |
891 | if (is_acpi_node(fwnode)) { |
892 | pwm = acpi_pwm_get(fwnode); |
893 | if (!IS_ERR(ptr: pwm) || PTR_ERR(ptr: pwm) != -ENOENT) |
894 | return pwm; |
895 | } |
896 | |
897 | /* |
898 | * We look up the provider in the static table typically provided by |
899 | * board setup code. We first try to lookup the consumer device by |
900 | * name. If the consumer device was passed in as NULL or if no match |
901 | * was found, we try to find the consumer by directly looking it up |
902 | * by name. |
903 | * |
904 | * If a match is found, the provider PWM chip is looked up by name |
905 | * and a PWM device is requested using the PWM device per-chip index. |
906 | * |
907 | * The lookup algorithm was shamelessly taken from the clock |
908 | * framework: |
909 | * |
910 | * We do slightly fuzzy matching here: |
911 | * An entry with a NULL ID is assumed to be a wildcard. |
912 | * If an entry has a device ID, it must match |
913 | * If an entry has a connection ID, it must match |
914 | * Then we take the most specific entry - with the following order |
915 | * of precedence: dev+con > dev only > con only. |
916 | */ |
917 | mutex_lock(&pwm_lookup_lock); |
918 | |
919 | list_for_each_entry(p, &pwm_lookup_list, list) { |
920 | match = 0; |
921 | |
922 | if (p->dev_id) { |
923 | if (!dev_id || strcmp(p->dev_id, dev_id)) |
924 | continue; |
925 | |
926 | match += 2; |
927 | } |
928 | |
929 | if (p->con_id) { |
930 | if (!con_id || strcmp(p->con_id, con_id)) |
931 | continue; |
932 | |
933 | match += 1; |
934 | } |
935 | |
936 | if (match > best) { |
937 | chosen = p; |
938 | |
939 | if (match != 3) |
940 | best = match; |
941 | else |
942 | break; |
943 | } |
944 | } |
945 | |
946 | mutex_unlock(lock: &pwm_lookup_lock); |
947 | |
948 | if (!chosen) |
949 | return ERR_PTR(error: -ENODEV); |
950 | |
951 | chip = pwmchip_find_by_name(name: chosen->provider); |
952 | |
953 | /* |
954 | * If the lookup entry specifies a module, load the module and retry |
955 | * the PWM chip lookup. This can be used to work around driver load |
956 | * ordering issues if driver's can't be made to properly support the |
957 | * deferred probe mechanism. |
958 | */ |
959 | if (!chip && chosen->module) { |
960 | err = request_module(chosen->module); |
961 | if (err == 0) |
962 | chip = pwmchip_find_by_name(name: chosen->provider); |
963 | } |
964 | |
965 | if (!chip) |
966 | return ERR_PTR(error: -EPROBE_DEFER); |
967 | |
968 | pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); |
969 | if (IS_ERR(ptr: pwm)) |
970 | return pwm; |
971 | |
972 | dl = pwm_device_link_add(dev, pwm); |
973 | if (IS_ERR(ptr: dl)) { |
974 | pwm_put(pwm); |
975 | return ERR_CAST(ptr: dl); |
976 | } |
977 | |
978 | pwm->args.period = chosen->period; |
979 | pwm->args.polarity = chosen->polarity; |
980 | |
981 | return pwm; |
982 | } |
983 | EXPORT_SYMBOL_GPL(pwm_get); |
984 | |
985 | /** |
986 | * pwm_put() - release a PWM device |
987 | * @pwm: PWM device |
988 | */ |
989 | void pwm_put(struct pwm_device *pwm) |
990 | { |
991 | if (!pwm) |
992 | return; |
993 | |
994 | mutex_lock(&pwm_lock); |
995 | |
996 | if (!test_and_clear_bit(nr: PWMF_REQUESTED, addr: &pwm->flags)) { |
997 | pr_warn("PWM device already freed\n" ); |
998 | goto out; |
999 | } |
1000 | |
1001 | if (pwm->chip->ops->free) |
1002 | pwm->chip->ops->free(pwm->chip, pwm); |
1003 | |
1004 | pwm->label = NULL; |
1005 | |
1006 | module_put(module: pwm->chip->owner); |
1007 | out: |
1008 | mutex_unlock(lock: &pwm_lock); |
1009 | } |
1010 | EXPORT_SYMBOL_GPL(pwm_put); |
1011 | |
1012 | static void devm_pwm_release(void *pwm) |
1013 | { |
1014 | pwm_put(pwm); |
1015 | } |
1016 | |
1017 | /** |
1018 | * devm_pwm_get() - resource managed pwm_get() |
1019 | * @dev: device for PWM consumer |
1020 | * @con_id: consumer name |
1021 | * |
1022 | * This function performs like pwm_get() but the acquired PWM device will |
1023 | * automatically be released on driver detach. |
1024 | * |
1025 | * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
1026 | * error code on failure. |
1027 | */ |
1028 | struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id) |
1029 | { |
1030 | struct pwm_device *pwm; |
1031 | int ret; |
1032 | |
1033 | pwm = pwm_get(dev, con_id); |
1034 | if (IS_ERR(ptr: pwm)) |
1035 | return pwm; |
1036 | |
1037 | ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm); |
1038 | if (ret) |
1039 | return ERR_PTR(error: ret); |
1040 | |
1041 | return pwm; |
1042 | } |
1043 | EXPORT_SYMBOL_GPL(devm_pwm_get); |
1044 | |
1045 | /** |
1046 | * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node |
1047 | * @dev: device for PWM consumer |
1048 | * @fwnode: firmware node to get the PWM from |
1049 | * @con_id: consumer name |
1050 | * |
1051 | * Returns the PWM device parsed from the firmware node. See of_pwm_get() and |
1052 | * acpi_pwm_get() for a detailed description. |
1053 | * |
1054 | * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded |
1055 | * error code on failure. |
1056 | */ |
1057 | struct pwm_device *devm_fwnode_pwm_get(struct device *dev, |
1058 | struct fwnode_handle *fwnode, |
1059 | const char *con_id) |
1060 | { |
1061 | struct pwm_device *pwm = ERR_PTR(error: -ENODEV); |
1062 | int ret; |
1063 | |
1064 | if (is_of_node(fwnode)) |
1065 | pwm = of_pwm_get(dev, to_of_node(fwnode), con_id); |
1066 | else if (is_acpi_node(fwnode)) |
1067 | pwm = acpi_pwm_get(fwnode); |
1068 | if (IS_ERR(ptr: pwm)) |
1069 | return pwm; |
1070 | |
1071 | ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm); |
1072 | if (ret) |
1073 | return ERR_PTR(error: ret); |
1074 | |
1075 | return pwm; |
1076 | } |
1077 | EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get); |
1078 | |
1079 | #ifdef CONFIG_DEBUG_FS |
1080 | static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) |
1081 | { |
1082 | unsigned int i; |
1083 | |
1084 | for (i = 0; i < chip->npwm; i++) { |
1085 | struct pwm_device *pwm = &chip->pwms[i]; |
1086 | struct pwm_state state; |
1087 | |
1088 | pwm_get_state(pwm, state: &state); |
1089 | |
1090 | seq_printf(m: s, fmt: " pwm-%-3d (%-20.20s):" , i, pwm->label); |
1091 | |
1092 | if (test_bit(PWMF_REQUESTED, &pwm->flags)) |
1093 | seq_puts(m: s, s: " requested" ); |
1094 | |
1095 | if (state.enabled) |
1096 | seq_puts(m: s, s: " enabled" ); |
1097 | |
1098 | seq_printf(m: s, fmt: " period: %llu ns" , state.period); |
1099 | seq_printf(m: s, fmt: " duty: %llu ns" , state.duty_cycle); |
1100 | seq_printf(m: s, fmt: " polarity: %s" , |
1101 | state.polarity ? "inverse" : "normal" ); |
1102 | |
1103 | if (state.usage_power) |
1104 | seq_puts(m: s, s: " usage_power" ); |
1105 | |
1106 | seq_puts(m: s, s: "\n" ); |
1107 | } |
1108 | } |
1109 | |
1110 | static void *pwm_seq_start(struct seq_file *s, loff_t *pos) |
1111 | { |
1112 | unsigned long id = *pos; |
1113 | void *ret; |
1114 | |
1115 | mutex_lock(&pwm_lock); |
1116 | s->private = "" ; |
1117 | |
1118 | ret = idr_get_next_ul(&pwm_chips, nextid: &id); |
1119 | *pos = id; |
1120 | return ret; |
1121 | } |
1122 | |
1123 | static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos) |
1124 | { |
1125 | unsigned long id = *pos + 1; |
1126 | void *ret; |
1127 | |
1128 | s->private = "\n" ; |
1129 | |
1130 | ret = idr_get_next_ul(&pwm_chips, nextid: &id); |
1131 | *pos = id; |
1132 | return ret; |
1133 | } |
1134 | |
1135 | static void pwm_seq_stop(struct seq_file *s, void *v) |
1136 | { |
1137 | mutex_unlock(lock: &pwm_lock); |
1138 | } |
1139 | |
1140 | static int pwm_seq_show(struct seq_file *s, void *v) |
1141 | { |
1142 | struct pwm_chip *chip = v; |
1143 | |
1144 | seq_printf(m: s, fmt: "%s%d: %s/%s, %d PWM device%s\n" , |
1145 | (char *)s->private, chip->id, |
1146 | pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus" , |
1147 | dev_name(dev: pwmchip_parent(chip)), chip->npwm, |
1148 | (chip->npwm != 1) ? "s" : "" ); |
1149 | |
1150 | pwm_dbg_show(chip, s); |
1151 | |
1152 | return 0; |
1153 | } |
1154 | |
1155 | static const struct seq_operations pwm_debugfs_sops = { |
1156 | .start = pwm_seq_start, |
1157 | .next = pwm_seq_next, |
1158 | .stop = pwm_seq_stop, |
1159 | .show = pwm_seq_show, |
1160 | }; |
1161 | |
1162 | DEFINE_SEQ_ATTRIBUTE(pwm_debugfs); |
1163 | |
1164 | static int __init pwm_debugfs_init(void) |
1165 | { |
1166 | debugfs_create_file(name: "pwm" , mode: 0444, NULL, NULL, fops: &pwm_debugfs_fops); |
1167 | |
1168 | return 0; |
1169 | } |
1170 | subsys_initcall(pwm_debugfs_init); |
1171 | #endif /* CONFIG_DEBUG_FS */ |
1172 | |