1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __LINUX_PWM_H |
3 | #define __LINUX_PWM_H |
4 | |
5 | #include <linux/err.h> |
6 | #include <linux/mutex.h> |
7 | #include <linux/of.h> |
8 | |
9 | struct pwm_chip; |
10 | |
11 | /** |
12 | * enum pwm_polarity - polarity of a PWM signal |
13 | * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- |
14 | * cycle, followed by a low signal for the remainder of the pulse |
15 | * period |
16 | * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- |
17 | * cycle, followed by a high signal for the remainder of the pulse |
18 | * period |
19 | */ |
20 | enum pwm_polarity { |
21 | PWM_POLARITY_NORMAL, |
22 | PWM_POLARITY_INVERSED, |
23 | }; |
24 | |
25 | /** |
26 | * struct pwm_args - board-dependent PWM arguments |
27 | * @period: reference period |
28 | * @polarity: reference polarity |
29 | * |
30 | * This structure describes board-dependent arguments attached to a PWM |
31 | * device. These arguments are usually retrieved from the PWM lookup table or |
32 | * device tree. |
33 | * |
34 | * Do not confuse this with the PWM state: PWM arguments represent the initial |
35 | * configuration that users want to use on this PWM device rather than the |
36 | * current PWM hardware state. |
37 | */ |
38 | struct pwm_args { |
39 | u64 period; |
40 | enum pwm_polarity polarity; |
41 | }; |
42 | |
43 | enum { |
44 | PWMF_REQUESTED = 0, |
45 | PWMF_EXPORTED = 1, |
46 | }; |
47 | |
48 | /* |
49 | * struct pwm_state - state of a PWM channel |
50 | * @period: PWM period (in nanoseconds) |
51 | * @duty_cycle: PWM duty cycle (in nanoseconds) |
52 | * @polarity: PWM polarity |
53 | * @enabled: PWM enabled status |
54 | * @usage_power: If set, the PWM driver is only required to maintain the power |
55 | * output but has more freedom regarding signal form. |
56 | * If supported, the signal can be optimized, for example to |
57 | * improve EMI by phase shifting individual channels. |
58 | */ |
59 | struct pwm_state { |
60 | u64 period; |
61 | u64 duty_cycle; |
62 | enum pwm_polarity polarity; |
63 | bool enabled; |
64 | bool usage_power; |
65 | }; |
66 | |
67 | /** |
68 | * struct pwm_device - PWM channel object |
69 | * @label: name of the PWM device |
70 | * @flags: flags associated with the PWM device |
71 | * @hwpwm: per-chip relative index of the PWM device |
72 | * @chip: PWM chip providing this PWM device |
73 | * @args: PWM arguments |
74 | * @state: last applied state |
75 | * @last: last implemented state (for PWM_DEBUG) |
76 | */ |
77 | struct pwm_device { |
78 | const char *label; |
79 | unsigned long flags; |
80 | unsigned int hwpwm; |
81 | struct pwm_chip *chip; |
82 | |
83 | struct pwm_args args; |
84 | struct pwm_state state; |
85 | struct pwm_state last; |
86 | }; |
87 | |
88 | /** |
89 | * pwm_get_state() - retrieve the current PWM state |
90 | * @pwm: PWM device |
91 | * @state: state to fill with the current PWM state |
92 | * |
93 | * The returned PWM state represents the state that was applied by a previous call to |
94 | * pwm_apply_might_sleep(). Drivers may have to slightly tweak that state before programming it to |
95 | * hardware. If pwm_apply_might_sleep() was never called, this returns either the current hardware |
96 | * state (if supported) or the default settings. |
97 | */ |
98 | static inline void pwm_get_state(const struct pwm_device *pwm, |
99 | struct pwm_state *state) |
100 | { |
101 | *state = pwm->state; |
102 | } |
103 | |
104 | static inline bool pwm_is_enabled(const struct pwm_device *pwm) |
105 | { |
106 | struct pwm_state state; |
107 | |
108 | pwm_get_state(pwm, state: &state); |
109 | |
110 | return state.enabled; |
111 | } |
112 | |
113 | static inline u64 pwm_get_period(const struct pwm_device *pwm) |
114 | { |
115 | struct pwm_state state; |
116 | |
117 | pwm_get_state(pwm, state: &state); |
118 | |
119 | return state.period; |
120 | } |
121 | |
122 | static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm) |
123 | { |
124 | struct pwm_state state; |
125 | |
126 | pwm_get_state(pwm, state: &state); |
127 | |
128 | return state.duty_cycle; |
129 | } |
130 | |
131 | static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) |
132 | { |
133 | struct pwm_state state; |
134 | |
135 | pwm_get_state(pwm, state: &state); |
136 | |
137 | return state.polarity; |
138 | } |
139 | |
140 | static inline void pwm_get_args(const struct pwm_device *pwm, |
141 | struct pwm_args *args) |
142 | { |
143 | *args = pwm->args; |
144 | } |
145 | |
146 | /** |
147 | * pwm_init_state() - prepare a new state to be applied with pwm_apply_might_sleep() |
148 | * @pwm: PWM device |
149 | * @state: state to fill with the prepared PWM state |
150 | * |
151 | * This functions prepares a state that can later be tweaked and applied |
152 | * to the PWM device with pwm_apply_might_sleep(). This is a convenient function |
153 | * that first retrieves the current PWM state and the replaces the period |
154 | * and polarity fields with the reference values defined in pwm->args. |
155 | * Once the function returns, you can adjust the ->enabled and ->duty_cycle |
156 | * fields according to your needs before calling pwm_apply_might_sleep(). |
157 | * |
158 | * ->duty_cycle is initially set to zero to avoid cases where the current |
159 | * ->duty_cycle value exceed the pwm_args->period one, which would trigger |
160 | * an error if the user calls pwm_apply_might_sleep() without adjusting ->duty_cycle |
161 | * first. |
162 | */ |
163 | static inline void pwm_init_state(const struct pwm_device *pwm, |
164 | struct pwm_state *state) |
165 | { |
166 | struct pwm_args args; |
167 | |
168 | /* First get the current state. */ |
169 | pwm_get_state(pwm, state); |
170 | |
171 | /* Then fill it with the reference config */ |
172 | pwm_get_args(pwm, args: &args); |
173 | |
174 | state->period = args.period; |
175 | state->polarity = args.polarity; |
176 | state->duty_cycle = 0; |
177 | state->usage_power = false; |
178 | } |
179 | |
180 | /** |
181 | * pwm_get_relative_duty_cycle() - Get a relative duty cycle value |
182 | * @state: PWM state to extract the duty cycle from |
183 | * @scale: target scale of the relative duty cycle |
184 | * |
185 | * This functions converts the absolute duty cycle stored in @state (expressed |
186 | * in nanosecond) into a value relative to the period. |
187 | * |
188 | * For example if you want to get the duty_cycle expressed in percent, call: |
189 | * |
190 | * pwm_get_state(pwm, &state); |
191 | * duty = pwm_get_relative_duty_cycle(&state, 100); |
192 | */ |
193 | static inline unsigned int |
194 | pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) |
195 | { |
196 | if (!state->period) |
197 | return 0; |
198 | |
199 | return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, |
200 | state->period); |
201 | } |
202 | |
203 | /** |
204 | * pwm_set_relative_duty_cycle() - Set a relative duty cycle value |
205 | * @state: PWM state to fill |
206 | * @duty_cycle: relative duty cycle value |
207 | * @scale: scale in which @duty_cycle is expressed |
208 | * |
209 | * This functions converts a relative into an absolute duty cycle (expressed |
210 | * in nanoseconds), and puts the result in state->duty_cycle. |
211 | * |
212 | * For example if you want to configure a 50% duty cycle, call: |
213 | * |
214 | * pwm_init_state(pwm, &state); |
215 | * pwm_set_relative_duty_cycle(&state, 50, 100); |
216 | * pwm_apply_might_sleep(pwm, &state); |
217 | * |
218 | * This functions returns -EINVAL if @duty_cycle and/or @scale are |
219 | * inconsistent (@scale == 0 or @duty_cycle > @scale). |
220 | */ |
221 | static inline int |
222 | pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, |
223 | unsigned int scale) |
224 | { |
225 | if (!scale || duty_cycle > scale) |
226 | return -EINVAL; |
227 | |
228 | state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * |
229 | state->period, |
230 | scale); |
231 | |
232 | return 0; |
233 | } |
234 | |
235 | /** |
236 | * struct pwm_capture - PWM capture data |
237 | * @period: period of the PWM signal (in nanoseconds) |
238 | * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) |
239 | */ |
240 | struct pwm_capture { |
241 | unsigned int period; |
242 | unsigned int duty_cycle; |
243 | }; |
244 | |
245 | /** |
246 | * struct pwm_ops - PWM controller operations |
247 | * @request: optional hook for requesting a PWM |
248 | * @free: optional hook for freeing a PWM |
249 | * @capture: capture and report PWM signal |
250 | * @apply: atomically apply a new PWM config |
251 | * @get_state: get the current PWM state. This function is only |
252 | * called once per PWM device when the PWM chip is |
253 | * registered. |
254 | */ |
255 | struct pwm_ops { |
256 | int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); |
257 | void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); |
258 | int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, |
259 | struct pwm_capture *result, unsigned long timeout); |
260 | int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, |
261 | const struct pwm_state *state); |
262 | int (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, |
263 | struct pwm_state *state); |
264 | }; |
265 | |
266 | /** |
267 | * struct pwm_chip - abstract a PWM controller |
268 | * @dev: device providing the PWMs |
269 | * @ops: callbacks for this PWM controller |
270 | * @owner: module providing this chip |
271 | * @id: unique number of this PWM chip |
272 | * @npwm: number of PWMs controlled by this chip |
273 | * @of_xlate: request a PWM device given a device tree PWM specifier |
274 | * @atomic: can the driver's ->apply() be called in atomic context |
275 | * @driver_data: Private pointer for driver specific info |
276 | * @pwms: array of PWM devices allocated by the framework |
277 | */ |
278 | struct pwm_chip { |
279 | struct device *dev; |
280 | const struct pwm_ops *ops; |
281 | struct module *owner; |
282 | unsigned int id; |
283 | unsigned int npwm; |
284 | |
285 | struct pwm_device * (*of_xlate)(struct pwm_chip *chip, |
286 | const struct of_phandle_args *args); |
287 | bool atomic; |
288 | |
289 | /* only used internally by the PWM framework */ |
290 | void *driver_data; |
291 | struct pwm_device *pwms; |
292 | }; |
293 | |
294 | static inline struct device *pwmchip_parent(const struct pwm_chip *chip) |
295 | { |
296 | return chip->dev; |
297 | } |
298 | |
299 | static inline void *pwmchip_get_drvdata(struct pwm_chip *chip) |
300 | { |
301 | /* |
302 | * After pwm_chip got a dedicated struct device, this can be replaced by |
303 | * dev_get_drvdata(&chip->dev); |
304 | */ |
305 | return chip->driver_data; |
306 | } |
307 | |
308 | static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data) |
309 | { |
310 | /* |
311 | * After pwm_chip got a dedicated struct device, this can be replaced by |
312 | * dev_set_drvdata(&chip->dev, data); |
313 | */ |
314 | chip->driver_data = data; |
315 | } |
316 | |
317 | #if IS_ENABLED(CONFIG_PWM) |
318 | /* PWM user APIs */ |
319 | int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state); |
320 | int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state); |
321 | int pwm_adjust_config(struct pwm_device *pwm); |
322 | |
323 | /** |
324 | * pwm_config() - change a PWM device configuration |
325 | * @pwm: PWM device |
326 | * @duty_ns: "on" time (in nanoseconds) |
327 | * @period_ns: duration (in nanoseconds) of one cycle |
328 | * |
329 | * Returns: 0 on success or a negative error code on failure. |
330 | */ |
331 | static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
332 | int period_ns) |
333 | { |
334 | struct pwm_state state; |
335 | |
336 | if (!pwm) |
337 | return -EINVAL; |
338 | |
339 | if (duty_ns < 0 || period_ns < 0) |
340 | return -EINVAL; |
341 | |
342 | pwm_get_state(pwm, state: &state); |
343 | if (state.duty_cycle == duty_ns && state.period == period_ns) |
344 | return 0; |
345 | |
346 | state.duty_cycle = duty_ns; |
347 | state.period = period_ns; |
348 | return pwm_apply_might_sleep(pwm, state: &state); |
349 | } |
350 | |
351 | /** |
352 | * pwm_enable() - start a PWM output toggling |
353 | * @pwm: PWM device |
354 | * |
355 | * Returns: 0 on success or a negative error code on failure. |
356 | */ |
357 | static inline int pwm_enable(struct pwm_device *pwm) |
358 | { |
359 | struct pwm_state state; |
360 | |
361 | if (!pwm) |
362 | return -EINVAL; |
363 | |
364 | pwm_get_state(pwm, state: &state); |
365 | if (state.enabled) |
366 | return 0; |
367 | |
368 | state.enabled = true; |
369 | return pwm_apply_might_sleep(pwm, state: &state); |
370 | } |
371 | |
372 | /** |
373 | * pwm_disable() - stop a PWM output toggling |
374 | * @pwm: PWM device |
375 | */ |
376 | static inline void pwm_disable(struct pwm_device *pwm) |
377 | { |
378 | struct pwm_state state; |
379 | |
380 | if (!pwm) |
381 | return; |
382 | |
383 | pwm_get_state(pwm, state: &state); |
384 | if (!state.enabled) |
385 | return; |
386 | |
387 | state.enabled = false; |
388 | pwm_apply_might_sleep(pwm, state: &state); |
389 | } |
390 | |
391 | /** |
392 | * pwm_might_sleep() - is pwm_apply_atomic() supported? |
393 | * @pwm: PWM device |
394 | * |
395 | * Returns: false if pwm_apply_atomic() can be called from atomic context. |
396 | */ |
397 | static inline bool pwm_might_sleep(struct pwm_device *pwm) |
398 | { |
399 | return !pwm->chip->atomic; |
400 | } |
401 | |
402 | /* PWM provider APIs */ |
403 | int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, |
404 | unsigned long timeout); |
405 | |
406 | void pwmchip_put(struct pwm_chip *chip); |
407 | struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); |
408 | struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); |
409 | |
410 | int __pwmchip_add(struct pwm_chip *chip, struct module *owner); |
411 | #define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE) |
412 | void pwmchip_remove(struct pwm_chip *chip); |
413 | |
414 | int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner); |
415 | #define devm_pwmchip_add(dev, chip) __devm_pwmchip_add(dev, chip, THIS_MODULE) |
416 | |
417 | struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
418 | unsigned int index, |
419 | const char *label); |
420 | |
421 | struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *chip, |
422 | const struct of_phandle_args *args); |
423 | struct pwm_device *of_pwm_single_xlate(struct pwm_chip *chip, |
424 | const struct of_phandle_args *args); |
425 | |
426 | struct pwm_device *pwm_get(struct device *dev, const char *con_id); |
427 | void pwm_put(struct pwm_device *pwm); |
428 | |
429 | struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); |
430 | struct pwm_device *devm_fwnode_pwm_get(struct device *dev, |
431 | struct fwnode_handle *fwnode, |
432 | const char *con_id); |
433 | #else |
434 | static inline bool pwm_might_sleep(struct pwm_device *pwm) |
435 | { |
436 | return true; |
437 | } |
438 | |
439 | static inline int pwm_apply_might_sleep(struct pwm_device *pwm, |
440 | const struct pwm_state *state) |
441 | { |
442 | might_sleep(); |
443 | return -EOPNOTSUPP; |
444 | } |
445 | |
446 | static inline int pwm_apply_atomic(struct pwm_device *pwm, |
447 | const struct pwm_state *state) |
448 | { |
449 | return -EOPNOTSUPP; |
450 | } |
451 | |
452 | static inline int pwm_adjust_config(struct pwm_device *pwm) |
453 | { |
454 | return -EOPNOTSUPP; |
455 | } |
456 | |
457 | static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
458 | int period_ns) |
459 | { |
460 | might_sleep(); |
461 | return -EINVAL; |
462 | } |
463 | |
464 | static inline int pwm_enable(struct pwm_device *pwm) |
465 | { |
466 | might_sleep(); |
467 | return -EINVAL; |
468 | } |
469 | |
470 | static inline void pwm_disable(struct pwm_device *pwm) |
471 | { |
472 | might_sleep(); |
473 | } |
474 | |
475 | static inline int pwm_capture(struct pwm_device *pwm, |
476 | struct pwm_capture *result, |
477 | unsigned long timeout) |
478 | { |
479 | return -EINVAL; |
480 | } |
481 | |
482 | static inline void pwmchip_put(struct pwm_chip *chip) |
483 | { |
484 | } |
485 | |
486 | static inline struct pwm_chip *pwmchip_alloc(struct device *parent, |
487 | unsigned int npwm, |
488 | size_t sizeof_priv) |
489 | { |
490 | return ERR_PTR(-EINVAL); |
491 | } |
492 | |
493 | static inline struct pwm_chip *devm_pwmchip_alloc(struct device *parent, |
494 | unsigned int npwm, |
495 | size_t sizeof_priv) |
496 | { |
497 | return pwmchip_alloc(parent, npwm, sizeof_priv); |
498 | } |
499 | |
500 | static inline int pwmchip_add(struct pwm_chip *chip) |
501 | { |
502 | return -EINVAL; |
503 | } |
504 | |
505 | static inline int pwmchip_remove(struct pwm_chip *chip) |
506 | { |
507 | return -EINVAL; |
508 | } |
509 | |
510 | static inline int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip) |
511 | { |
512 | return -EINVAL; |
513 | } |
514 | |
515 | static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
516 | unsigned int index, |
517 | const char *label) |
518 | { |
519 | might_sleep(); |
520 | return ERR_PTR(-ENODEV); |
521 | } |
522 | |
523 | static inline struct pwm_device *pwm_get(struct device *dev, |
524 | const char *consumer) |
525 | { |
526 | might_sleep(); |
527 | return ERR_PTR(-ENODEV); |
528 | } |
529 | |
530 | static inline void pwm_put(struct pwm_device *pwm) |
531 | { |
532 | might_sleep(); |
533 | } |
534 | |
535 | static inline struct pwm_device *devm_pwm_get(struct device *dev, |
536 | const char *consumer) |
537 | { |
538 | might_sleep(); |
539 | return ERR_PTR(-ENODEV); |
540 | } |
541 | |
542 | static inline struct pwm_device * |
543 | devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, |
544 | const char *con_id) |
545 | { |
546 | might_sleep(); |
547 | return ERR_PTR(-ENODEV); |
548 | } |
549 | #endif |
550 | |
551 | static inline void pwm_apply_args(struct pwm_device *pwm) |
552 | { |
553 | struct pwm_state state = { }; |
554 | |
555 | /* |
556 | * PWM users calling pwm_apply_args() expect to have a fresh config |
557 | * where the polarity and period are set according to pwm_args info. |
558 | * The problem is, polarity can only be changed when the PWM is |
559 | * disabled. |
560 | * |
561 | * PWM drivers supporting hardware readout may declare the PWM device |
562 | * as enabled, and prevent polarity setting, which changes from the |
563 | * existing behavior, where all PWM devices are declared as disabled |
564 | * at startup (even if they are actually enabled), thus authorizing |
565 | * polarity setting. |
566 | * |
567 | * To fulfill this requirement, we apply a new state which disables |
568 | * the PWM device and set the reference period and polarity config. |
569 | * |
570 | * Note that PWM users requiring a smooth handover between the |
571 | * bootloader and the kernel (like critical regulators controlled by |
572 | * PWM devices) will have to switch to the atomic API and avoid calling |
573 | * pwm_apply_args(). |
574 | */ |
575 | |
576 | state.enabled = false; |
577 | state.polarity = pwm->args.polarity; |
578 | state.period = pwm->args.period; |
579 | state.usage_power = false; |
580 | |
581 | pwm_apply_might_sleep(pwm, state: &state); |
582 | } |
583 | |
584 | /* only for backwards-compatibility, new code should not use this */ |
585 | static inline int pwm_apply_state(struct pwm_device *pwm, |
586 | const struct pwm_state *state) |
587 | { |
588 | return pwm_apply_might_sleep(pwm, state); |
589 | } |
590 | |
591 | struct pwm_lookup { |
592 | struct list_head list; |
593 | const char *provider; |
594 | unsigned int index; |
595 | const char *dev_id; |
596 | const char *con_id; |
597 | unsigned int period; |
598 | enum pwm_polarity polarity; |
599 | const char *module; /* optional, may be NULL */ |
600 | }; |
601 | |
602 | #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ |
603 | _period, _polarity, _module) \ |
604 | { \ |
605 | .provider = _provider, \ |
606 | .index = _index, \ |
607 | .dev_id = _dev_id, \ |
608 | .con_id = _con_id, \ |
609 | .period = _period, \ |
610 | .polarity = _polarity, \ |
611 | .module = _module, \ |
612 | } |
613 | |
614 | #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ |
615 | PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ |
616 | _polarity, NULL) |
617 | |
618 | #if IS_ENABLED(CONFIG_PWM) |
619 | void pwm_add_table(struct pwm_lookup *table, size_t num); |
620 | void pwm_remove_table(struct pwm_lookup *table, size_t num); |
621 | #else |
622 | static inline void pwm_add_table(struct pwm_lookup *table, size_t num) |
623 | { |
624 | } |
625 | |
626 | static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) |
627 | { |
628 | } |
629 | #endif |
630 | |
631 | #ifdef CONFIG_PWM_SYSFS |
632 | void pwmchip_sysfs_export(struct pwm_chip *chip); |
633 | void pwmchip_sysfs_unexport(struct pwm_chip *chip); |
634 | #else |
635 | static inline void pwmchip_sysfs_export(struct pwm_chip *chip) |
636 | { |
637 | } |
638 | |
639 | static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
640 | { |
641 | } |
642 | #endif /* CONFIG_PWM_SYSFS */ |
643 | |
644 | #endif /* __LINUX_PWM_H */ |
645 | |