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 = 1 << 0, |
45 | PWMF_EXPORTED = 1 << 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 | * @pwm: global index of the PWM device |
73 | * @chip: PWM chip providing this PWM device |
74 | * @chip_data: chip-private data associated with the PWM device |
75 | * @args: PWM arguments |
76 | * @state: last applied state |
77 | * @last: last implemented state (for PWM_DEBUG) |
78 | */ |
79 | struct pwm_device { |
80 | const char *label; |
81 | unsigned long flags; |
82 | unsigned int hwpwm; |
83 | unsigned int pwm; |
84 | struct pwm_chip *chip; |
85 | void *chip_data; |
86 | |
87 | struct pwm_args args; |
88 | struct pwm_state state; |
89 | struct pwm_state last; |
90 | }; |
91 | |
92 | /** |
93 | * pwm_get_state() - retrieve the current PWM state |
94 | * @pwm: PWM device |
95 | * @state: state to fill with the current PWM state |
96 | * |
97 | * The returned PWM state represents the state that was applied by a previous call to |
98 | * pwm_apply_state(). Drivers may have to slightly tweak that state before programming it to |
99 | * hardware. If pwm_apply_state() was never called, this returns either the current hardware |
100 | * state (if supported) or the default settings. |
101 | */ |
102 | static inline void pwm_get_state(const struct pwm_device *pwm, |
103 | struct pwm_state *state) |
104 | { |
105 | *state = pwm->state; |
106 | } |
107 | |
108 | static inline bool pwm_is_enabled(const struct pwm_device *pwm) |
109 | { |
110 | struct pwm_state state; |
111 | |
112 | pwm_get_state(pwm, state: &state); |
113 | |
114 | return state.enabled; |
115 | } |
116 | |
117 | static inline void pwm_set_period(struct pwm_device *pwm, u64 period) |
118 | { |
119 | if (pwm) |
120 | pwm->state.period = period; |
121 | } |
122 | |
123 | static inline u64 pwm_get_period(const struct pwm_device *pwm) |
124 | { |
125 | struct pwm_state state; |
126 | |
127 | pwm_get_state(pwm, state: &state); |
128 | |
129 | return state.period; |
130 | } |
131 | |
132 | static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty) |
133 | { |
134 | if (pwm) |
135 | pwm->state.duty_cycle = duty; |
136 | } |
137 | |
138 | static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm) |
139 | { |
140 | struct pwm_state state; |
141 | |
142 | pwm_get_state(pwm, state: &state); |
143 | |
144 | return state.duty_cycle; |
145 | } |
146 | |
147 | static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) |
148 | { |
149 | struct pwm_state state; |
150 | |
151 | pwm_get_state(pwm, state: &state); |
152 | |
153 | return state.polarity; |
154 | } |
155 | |
156 | static inline void pwm_get_args(const struct pwm_device *pwm, |
157 | struct pwm_args *args) |
158 | { |
159 | *args = pwm->args; |
160 | } |
161 | |
162 | /** |
163 | * pwm_init_state() - prepare a new state to be applied with pwm_apply_state() |
164 | * @pwm: PWM device |
165 | * @state: state to fill with the prepared PWM state |
166 | * |
167 | * This functions prepares a state that can later be tweaked and applied |
168 | * to the PWM device with pwm_apply_state(). This is a convenient function |
169 | * that first retrieves the current PWM state and the replaces the period |
170 | * and polarity fields with the reference values defined in pwm->args. |
171 | * Once the function returns, you can adjust the ->enabled and ->duty_cycle |
172 | * fields according to your needs before calling pwm_apply_state(). |
173 | * |
174 | * ->duty_cycle is initially set to zero to avoid cases where the current |
175 | * ->duty_cycle value exceed the pwm_args->period one, which would trigger |
176 | * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle |
177 | * first. |
178 | */ |
179 | static inline void pwm_init_state(const struct pwm_device *pwm, |
180 | struct pwm_state *state) |
181 | { |
182 | struct pwm_args args; |
183 | |
184 | /* First get the current state. */ |
185 | pwm_get_state(pwm, state); |
186 | |
187 | /* Then fill it with the reference config */ |
188 | pwm_get_args(pwm, args: &args); |
189 | |
190 | state->period = args.period; |
191 | state->polarity = args.polarity; |
192 | state->duty_cycle = 0; |
193 | state->usage_power = false; |
194 | } |
195 | |
196 | /** |
197 | * pwm_get_relative_duty_cycle() - Get a relative duty cycle value |
198 | * @state: PWM state to extract the duty cycle from |
199 | * @scale: target scale of the relative duty cycle |
200 | * |
201 | * This functions converts the absolute duty cycle stored in @state (expressed |
202 | * in nanosecond) into a value relative to the period. |
203 | * |
204 | * For example if you want to get the duty_cycle expressed in percent, call: |
205 | * |
206 | * pwm_get_state(pwm, &state); |
207 | * duty = pwm_get_relative_duty_cycle(&state, 100); |
208 | */ |
209 | static inline unsigned int |
210 | pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) |
211 | { |
212 | if (!state->period) |
213 | return 0; |
214 | |
215 | return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, |
216 | state->period); |
217 | } |
218 | |
219 | /** |
220 | * pwm_set_relative_duty_cycle() - Set a relative duty cycle value |
221 | * @state: PWM state to fill |
222 | * @duty_cycle: relative duty cycle value |
223 | * @scale: scale in which @duty_cycle is expressed |
224 | * |
225 | * This functions converts a relative into an absolute duty cycle (expressed |
226 | * in nanoseconds), and puts the result in state->duty_cycle. |
227 | * |
228 | * For example if you want to configure a 50% duty cycle, call: |
229 | * |
230 | * pwm_init_state(pwm, &state); |
231 | * pwm_set_relative_duty_cycle(&state, 50, 100); |
232 | * pwm_apply_state(pwm, &state); |
233 | * |
234 | * This functions returns -EINVAL if @duty_cycle and/or @scale are |
235 | * inconsistent (@scale == 0 or @duty_cycle > @scale). |
236 | */ |
237 | static inline int |
238 | pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, |
239 | unsigned int scale) |
240 | { |
241 | if (!scale || duty_cycle > scale) |
242 | return -EINVAL; |
243 | |
244 | state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * |
245 | state->period, |
246 | scale); |
247 | |
248 | return 0; |
249 | } |
250 | |
251 | /** |
252 | * struct pwm_capture - PWM capture data |
253 | * @period: period of the PWM signal (in nanoseconds) |
254 | * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) |
255 | */ |
256 | struct pwm_capture { |
257 | unsigned int period; |
258 | unsigned int duty_cycle; |
259 | }; |
260 | |
261 | /** |
262 | * struct pwm_ops - PWM controller operations |
263 | * @request: optional hook for requesting a PWM |
264 | * @free: optional hook for freeing a PWM |
265 | * @capture: capture and report PWM signal |
266 | * @apply: atomically apply a new PWM config |
267 | * @get_state: get the current PWM state. This function is only |
268 | * called once per PWM device when the PWM chip is |
269 | * registered. |
270 | * @owner: helps prevent removal of modules exporting active PWMs |
271 | */ |
272 | struct pwm_ops { |
273 | int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); |
274 | void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); |
275 | int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, |
276 | struct pwm_capture *result, unsigned long timeout); |
277 | int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, |
278 | const struct pwm_state *state); |
279 | int (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, |
280 | struct pwm_state *state); |
281 | struct module *owner; |
282 | }; |
283 | |
284 | /** |
285 | * struct pwm_chip - abstract a PWM controller |
286 | * @dev: device providing the PWMs |
287 | * @ops: callbacks for this PWM controller |
288 | * @base: number of first PWM controlled by this chip |
289 | * @npwm: number of PWMs controlled by this chip |
290 | * @of_xlate: request a PWM device given a device tree PWM specifier |
291 | * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier |
292 | * @list: list node for internal use |
293 | * @pwms: array of PWM devices allocated by the framework |
294 | */ |
295 | struct pwm_chip { |
296 | struct device *dev; |
297 | const struct pwm_ops *ops; |
298 | int base; |
299 | unsigned int npwm; |
300 | |
301 | struct pwm_device * (*of_xlate)(struct pwm_chip *chip, |
302 | const struct of_phandle_args *args); |
303 | unsigned int of_pwm_n_cells; |
304 | |
305 | /* only used internally by the PWM framework */ |
306 | struct list_head list; |
307 | struct pwm_device *pwms; |
308 | }; |
309 | |
310 | #if IS_ENABLED(CONFIG_PWM) |
311 | /* PWM user APIs */ |
312 | int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state); |
313 | int pwm_adjust_config(struct pwm_device *pwm); |
314 | |
315 | /** |
316 | * pwm_config() - change a PWM device configuration |
317 | * @pwm: PWM device |
318 | * @duty_ns: "on" time (in nanoseconds) |
319 | * @period_ns: duration (in nanoseconds) of one cycle |
320 | * |
321 | * Returns: 0 on success or a negative error code on failure. |
322 | */ |
323 | static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
324 | int period_ns) |
325 | { |
326 | struct pwm_state state; |
327 | |
328 | if (!pwm) |
329 | return -EINVAL; |
330 | |
331 | if (duty_ns < 0 || period_ns < 0) |
332 | return -EINVAL; |
333 | |
334 | pwm_get_state(pwm, state: &state); |
335 | if (state.duty_cycle == duty_ns && state.period == period_ns) |
336 | return 0; |
337 | |
338 | state.duty_cycle = duty_ns; |
339 | state.period = period_ns; |
340 | return pwm_apply_state(pwm, state: &state); |
341 | } |
342 | |
343 | /** |
344 | * pwm_enable() - start a PWM output toggling |
345 | * @pwm: PWM device |
346 | * |
347 | * Returns: 0 on success or a negative error code on failure. |
348 | */ |
349 | static inline int pwm_enable(struct pwm_device *pwm) |
350 | { |
351 | struct pwm_state state; |
352 | |
353 | if (!pwm) |
354 | return -EINVAL; |
355 | |
356 | pwm_get_state(pwm, state: &state); |
357 | if (state.enabled) |
358 | return 0; |
359 | |
360 | state.enabled = true; |
361 | return pwm_apply_state(pwm, state: &state); |
362 | } |
363 | |
364 | /** |
365 | * pwm_disable() - stop a PWM output toggling |
366 | * @pwm: PWM device |
367 | */ |
368 | static inline void pwm_disable(struct pwm_device *pwm) |
369 | { |
370 | struct pwm_state state; |
371 | |
372 | if (!pwm) |
373 | return; |
374 | |
375 | pwm_get_state(pwm, state: &state); |
376 | if (!state.enabled) |
377 | return; |
378 | |
379 | state.enabled = false; |
380 | pwm_apply_state(pwm, state: &state); |
381 | } |
382 | |
383 | /* PWM provider APIs */ |
384 | int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, |
385 | unsigned long timeout); |
386 | int pwm_set_chip_data(struct pwm_device *pwm, void *data); |
387 | void *pwm_get_chip_data(struct pwm_device *pwm); |
388 | |
389 | int pwmchip_add(struct pwm_chip *chip); |
390 | void pwmchip_remove(struct pwm_chip *chip); |
391 | |
392 | int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip); |
393 | |
394 | struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
395 | unsigned int index, |
396 | const char *label); |
397 | |
398 | struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *chip, |
399 | const struct of_phandle_args *args); |
400 | struct pwm_device *of_pwm_single_xlate(struct pwm_chip *chip, |
401 | const struct of_phandle_args *args); |
402 | |
403 | struct pwm_device *pwm_get(struct device *dev, const char *con_id); |
404 | void pwm_put(struct pwm_device *pwm); |
405 | |
406 | struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); |
407 | struct pwm_device *devm_fwnode_pwm_get(struct device *dev, |
408 | struct fwnode_handle *fwnode, |
409 | const char *con_id); |
410 | #else |
411 | static inline int pwm_apply_state(struct pwm_device *pwm, |
412 | const struct pwm_state *state) |
413 | { |
414 | might_sleep(); |
415 | return -ENOTSUPP; |
416 | } |
417 | |
418 | static inline int pwm_adjust_config(struct pwm_device *pwm) |
419 | { |
420 | return -ENOTSUPP; |
421 | } |
422 | |
423 | static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
424 | int period_ns) |
425 | { |
426 | might_sleep(); |
427 | return -EINVAL; |
428 | } |
429 | |
430 | static inline int pwm_enable(struct pwm_device *pwm) |
431 | { |
432 | might_sleep(); |
433 | return -EINVAL; |
434 | } |
435 | |
436 | static inline void pwm_disable(struct pwm_device *pwm) |
437 | { |
438 | might_sleep(); |
439 | } |
440 | |
441 | static inline int pwm_capture(struct pwm_device *pwm, |
442 | struct pwm_capture *result, |
443 | unsigned long timeout) |
444 | { |
445 | return -EINVAL; |
446 | } |
447 | |
448 | static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) |
449 | { |
450 | return -EINVAL; |
451 | } |
452 | |
453 | static inline void *pwm_get_chip_data(struct pwm_device *pwm) |
454 | { |
455 | return NULL; |
456 | } |
457 | |
458 | static inline int pwmchip_add(struct pwm_chip *chip) |
459 | { |
460 | return -EINVAL; |
461 | } |
462 | |
463 | static inline int pwmchip_remove(struct pwm_chip *chip) |
464 | { |
465 | return -EINVAL; |
466 | } |
467 | |
468 | static inline int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip) |
469 | { |
470 | return -EINVAL; |
471 | } |
472 | |
473 | static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
474 | unsigned int index, |
475 | const char *label) |
476 | { |
477 | might_sleep(); |
478 | return ERR_PTR(-ENODEV); |
479 | } |
480 | |
481 | static inline struct pwm_device *pwm_get(struct device *dev, |
482 | const char *consumer) |
483 | { |
484 | might_sleep(); |
485 | return ERR_PTR(-ENODEV); |
486 | } |
487 | |
488 | static inline void pwm_put(struct pwm_device *pwm) |
489 | { |
490 | might_sleep(); |
491 | } |
492 | |
493 | static inline struct pwm_device *devm_pwm_get(struct device *dev, |
494 | const char *consumer) |
495 | { |
496 | might_sleep(); |
497 | return ERR_PTR(-ENODEV); |
498 | } |
499 | |
500 | static inline struct pwm_device * |
501 | devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, |
502 | const char *con_id) |
503 | { |
504 | might_sleep(); |
505 | return ERR_PTR(-ENODEV); |
506 | } |
507 | #endif |
508 | |
509 | static inline void pwm_apply_args(struct pwm_device *pwm) |
510 | { |
511 | struct pwm_state state = { }; |
512 | |
513 | /* |
514 | * PWM users calling pwm_apply_args() expect to have a fresh config |
515 | * where the polarity and period are set according to pwm_args info. |
516 | * The problem is, polarity can only be changed when the PWM is |
517 | * disabled. |
518 | * |
519 | * PWM drivers supporting hardware readout may declare the PWM device |
520 | * as enabled, and prevent polarity setting, which changes from the |
521 | * existing behavior, where all PWM devices are declared as disabled |
522 | * at startup (even if they are actually enabled), thus authorizing |
523 | * polarity setting. |
524 | * |
525 | * To fulfill this requirement, we apply a new state which disables |
526 | * the PWM device and set the reference period and polarity config. |
527 | * |
528 | * Note that PWM users requiring a smooth handover between the |
529 | * bootloader and the kernel (like critical regulators controlled by |
530 | * PWM devices) will have to switch to the atomic API and avoid calling |
531 | * pwm_apply_args(). |
532 | */ |
533 | |
534 | state.enabled = false; |
535 | state.polarity = pwm->args.polarity; |
536 | state.period = pwm->args.period; |
537 | state.usage_power = false; |
538 | |
539 | pwm_apply_state(pwm, state: &state); |
540 | } |
541 | |
542 | struct pwm_lookup { |
543 | struct list_head list; |
544 | const char *provider; |
545 | unsigned int index; |
546 | const char *dev_id; |
547 | const char *con_id; |
548 | unsigned int period; |
549 | enum pwm_polarity polarity; |
550 | const char *module; /* optional, may be NULL */ |
551 | }; |
552 | |
553 | #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ |
554 | _period, _polarity, _module) \ |
555 | { \ |
556 | .provider = _provider, \ |
557 | .index = _index, \ |
558 | .dev_id = _dev_id, \ |
559 | .con_id = _con_id, \ |
560 | .period = _period, \ |
561 | .polarity = _polarity, \ |
562 | .module = _module, \ |
563 | } |
564 | |
565 | #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ |
566 | PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ |
567 | _polarity, NULL) |
568 | |
569 | #if IS_ENABLED(CONFIG_PWM) |
570 | void pwm_add_table(struct pwm_lookup *table, size_t num); |
571 | void pwm_remove_table(struct pwm_lookup *table, size_t num); |
572 | #else |
573 | static inline void pwm_add_table(struct pwm_lookup *table, size_t num) |
574 | { |
575 | } |
576 | |
577 | static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) |
578 | { |
579 | } |
580 | #endif |
581 | |
582 | #ifdef CONFIG_PWM_SYSFS |
583 | void pwmchip_sysfs_export(struct pwm_chip *chip); |
584 | void pwmchip_sysfs_unexport(struct pwm_chip *chip); |
585 | #else |
586 | static inline void pwmchip_sysfs_export(struct pwm_chip *chip) |
587 | { |
588 | } |
589 | |
590 | static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
591 | { |
592 | } |
593 | #endif /* CONFIG_PWM_SYSFS */ |
594 | |
595 | #endif /* __LINUX_PWM_H */ |
596 | |