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