1 /* SPDX-License-Identifier: GPL-2.0 */
6 #include <linux/mutex.h>
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
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
25 PWM_POLARITY_INVERSED,
29 * struct pwm_args - board-dependent PWM arguments
30 * @period: reference period
31 * @polarity: reference polarity
33 * This structure describes board-dependent arguments attached to a PWM
34 * device. These arguments are usually retrieved from the PWM lookup table or
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.
43 enum pwm_polarity polarity;
47 PWMF_REQUESTED = 1 << 0,
48 PWMF_EXPORTED = 1 << 1,
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
60 unsigned int duty_cycle;
61 enum pwm_polarity polarity;
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
81 struct pwm_chip *chip;
85 struct pwm_state state;
89 * pwm_get_state() - retrieve the current PWM state
91 * @state: state to fill with the current PWM state
93 static inline void pwm_get_state(const struct pwm_device *pwm,
94 struct pwm_state *state)
99 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
101 struct pwm_state state;
103 pwm_get_state(pwm, &state);
105 return state.enabled;
108 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
111 pwm->state.period = period;
114 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
116 struct pwm_state state;
118 pwm_get_state(pwm, &state);
123 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
126 pwm->state.duty_cycle = duty;
129 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
131 struct pwm_state state;
133 pwm_get_state(pwm, &state);
135 return state.duty_cycle;
138 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
140 struct pwm_state state;
142 pwm_get_state(pwm, &state);
144 return state.polarity;
147 static inline void pwm_get_args(const struct pwm_device *pwm,
148 struct pwm_args *args)
154 * pwm_init_state() - prepare a new state to be applied with pwm_apply_state()
156 * @state: state to fill with the prepared PWM state
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().
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
170 static inline void pwm_init_state(const struct pwm_device *pwm,
171 struct pwm_state *state)
173 struct pwm_args args;
175 /* First get the current state. */
176 pwm_get_state(pwm, state);
178 /* Then fill it with the reference config */
179 pwm_get_args(pwm, &args);
181 state->period = args.period;
182 state->polarity = args.polarity;
183 state->duty_cycle = 0;
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
191 * This functions converts the absolute duty cycle stored in @state (expressed
192 * in nanosecond) into a value relative to the period.
194 * For example if you want to get the duty_cycle expressed in percent, call:
196 * pwm_get_state(pwm, &state);
197 * duty = pwm_get_relative_duty_cycle(&state, 100);
199 static inline unsigned int
200 pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale)
205 return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale,
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
215 * This functions converts a relative into an absolute duty cycle (expressed
216 * in nanoseconds), and puts the result in state->duty_cycle.
218 * For example if you want to configure a 50% duty cycle, call:
220 * pwm_init_state(pwm, &state);
221 * pwm_set_relative_duty_cycle(&state, 50, 100);
222 * pwm_apply_state(pwm, &state);
224 * This functions returns -EINVAL if @duty_cycle and/or @scale are
225 * inconsistent (@scale == 0 or @duty_cycle > @scale).
228 pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
231 if (!scale || duty_cycle > scale)
234 state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle *
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
250 * @get_state: get the current PWM state. This function is only
251 * called once per PWM device when the PWM chip is
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
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;
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);
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
292 const struct pwm_ops *ops;
296 struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
297 const struct of_phandle_args *args);
298 unsigned int of_pwm_n_cells;
300 /* only used internally by the PWM framework */
301 struct list_head list;
302 struct pwm_device *pwms;
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)
312 unsigned int duty_cycle;
315 #if IS_ENABLED(CONFIG_PWM)
317 struct pwm_device *pwm_request(int pwm_id, const char *label);
318 void pwm_free(struct pwm_device *pwm);
319 int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
320 int pwm_adjust_config(struct pwm_device *pwm);
323 * pwm_config() - change a PWM device configuration
325 * @duty_ns: "on" time (in nanoseconds)
326 * @period_ns: duration (in nanoseconds) of one cycle
328 * Returns: 0 on success or a negative error code on failure.
330 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
333 struct pwm_state state;
338 if (duty_ns < 0 || period_ns < 0)
341 pwm_get_state(pwm, &state);
342 if (state.duty_cycle == duty_ns && state.period == period_ns)
345 state.duty_cycle = duty_ns;
346 state.period = period_ns;
347 return pwm_apply_state(pwm, &state);
351 * pwm_enable() - start a PWM output toggling
354 * Returns: 0 on success or a negative error code on failure.
356 static inline int pwm_enable(struct pwm_device *pwm)
358 struct pwm_state state;
363 pwm_get_state(pwm, &state);
367 state.enabled = true;
368 return pwm_apply_state(pwm, &state);
372 * pwm_disable() - stop a PWM output toggling
375 static inline void pwm_disable(struct pwm_device *pwm)
377 struct pwm_state state;
382 pwm_get_state(pwm, &state);
386 state.enabled = false;
387 pwm_apply_state(pwm, &state);
390 /* PWM provider APIs */
391 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
392 unsigned long timeout);
393 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
394 void *pwm_get_chip_data(struct pwm_device *pwm);
396 int pwmchip_add_with_polarity(struct pwm_chip *chip,
397 enum pwm_polarity polarity);
398 int pwmchip_add(struct pwm_chip *chip);
399 int pwmchip_remove(struct pwm_chip *chip);
400 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
404 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
405 const struct of_phandle_args *args);
407 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
408 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
409 void pwm_put(struct pwm_device *pwm);
411 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
412 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
414 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
416 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
418 return ERR_PTR(-ENODEV);
421 static inline void pwm_free(struct pwm_device *pwm)
425 static inline int pwm_apply_state(struct pwm_device *pwm,
426 const struct pwm_state *state)
431 static inline int pwm_adjust_config(struct pwm_device *pwm)
436 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
442 static inline int pwm_capture(struct pwm_device *pwm,
443 struct pwm_capture *result,
444 unsigned long timeout)
449 static inline int pwm_enable(struct pwm_device *pwm)
454 static inline void pwm_disable(struct pwm_device *pwm)
458 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
463 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
468 static inline int pwmchip_add(struct pwm_chip *chip)
473 static inline int pwmchip_add_inversed(struct pwm_chip *chip)
478 static inline int pwmchip_remove(struct pwm_chip *chip)
483 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
487 return ERR_PTR(-ENODEV);
490 static inline struct pwm_device *pwm_get(struct device *dev,
491 const char *consumer)
493 return ERR_PTR(-ENODEV);
496 static inline struct pwm_device *of_pwm_get(struct device_node *np,
499 return ERR_PTR(-ENODEV);
502 static inline void pwm_put(struct pwm_device *pwm)
506 static inline struct pwm_device *devm_pwm_get(struct device *dev,
507 const char *consumer)
509 return ERR_PTR(-ENODEV);
512 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
513 struct device_node *np,
516 return ERR_PTR(-ENODEV);
519 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
524 static inline void pwm_apply_args(struct pwm_device *pwm)
526 struct pwm_state state = { };
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
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
540 * To fulfill this requirement, we apply a new state which disables
541 * the PWM device and set the reference period and polarity config.
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
549 state.enabled = false;
550 state.polarity = pwm->args.polarity;
551 state.period = pwm->args.period;
553 pwm_apply_state(pwm, &state);
557 struct list_head list;
558 const char *provider;
563 enum pwm_polarity polarity;
564 const char *module; /* optional, may be NULL */
567 #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \
568 _period, _polarity, _module) \
570 .provider = _provider, \
575 .polarity = _polarity, \
579 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
580 PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \
583 #if IS_ENABLED(CONFIG_PWM)
584 void pwm_add_table(struct pwm_lookup *table, size_t num);
585 void pwm_remove_table(struct pwm_lookup *table, size_t num);
587 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
591 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
596 #ifdef CONFIG_PWM_SYSFS
597 void pwmchip_sysfs_export(struct pwm_chip *chip);
598 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
600 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
604 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
607 #endif /* CONFIG_PWM_SYSFS */
609 #endif /* __LINUX_PWM_H */