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: last applied state
75 * @last: last implemented state (for PWM_DEBUG)
82 struct pwm_chip *chip;
86 struct pwm_state state;
87 struct pwm_state last;
91 * pwm_get_state() - retrieve the current PWM state
93 * @state: state to fill with the current PWM state
95 static inline void pwm_get_state(const struct pwm_device *pwm,
96 struct pwm_state *state)
101 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
103 struct pwm_state state;
105 pwm_get_state(pwm, &state);
107 return state.enabled;
110 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
113 pwm->state.period = period;
116 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
118 struct pwm_state state;
120 pwm_get_state(pwm, &state);
125 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
128 pwm->state.duty_cycle = duty;
131 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
133 struct pwm_state state;
135 pwm_get_state(pwm, &state);
137 return state.duty_cycle;
140 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
142 struct pwm_state state;
144 pwm_get_state(pwm, &state);
146 return state.polarity;
149 static inline void pwm_get_args(const struct pwm_device *pwm,
150 struct pwm_args *args)
156 * pwm_init_state() - prepare a new state to be applied with pwm_apply_state()
158 * @state: state to fill with the prepared PWM state
160 * This functions prepares a state that can later be tweaked and applied
161 * to the PWM device with pwm_apply_state(). This is a convenient function
162 * that first retrieves the current PWM state and the replaces the period
163 * and polarity fields with the reference values defined in pwm->args.
164 * Once the function returns, you can adjust the ->enabled and ->duty_cycle
165 * fields according to your needs before calling pwm_apply_state().
167 * ->duty_cycle is initially set to zero to avoid cases where the current
168 * ->duty_cycle value exceed the pwm_args->period one, which would trigger
169 * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle
172 static inline void pwm_init_state(const struct pwm_device *pwm,
173 struct pwm_state *state)
175 struct pwm_args args;
177 /* First get the current state. */
178 pwm_get_state(pwm, state);
180 /* Then fill it with the reference config */
181 pwm_get_args(pwm, &args);
183 state->period = args.period;
184 state->polarity = args.polarity;
185 state->duty_cycle = 0;
189 * pwm_get_relative_duty_cycle() - Get a relative duty cycle value
190 * @state: PWM state to extract the duty cycle from
191 * @scale: target scale of the relative duty cycle
193 * This functions converts the absolute duty cycle stored in @state (expressed
194 * in nanosecond) into a value relative to the period.
196 * For example if you want to get the duty_cycle expressed in percent, call:
198 * pwm_get_state(pwm, &state);
199 * duty = pwm_get_relative_duty_cycle(&state, 100);
201 static inline unsigned int
202 pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale)
207 return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale,
212 * pwm_set_relative_duty_cycle() - Set a relative duty cycle value
213 * @state: PWM state to fill
214 * @duty_cycle: relative duty cycle value
215 * @scale: scale in which @duty_cycle is expressed
217 * This functions converts a relative into an absolute duty cycle (expressed
218 * in nanoseconds), and puts the result in state->duty_cycle.
220 * For example if you want to configure a 50% duty cycle, call:
222 * pwm_init_state(pwm, &state);
223 * pwm_set_relative_duty_cycle(&state, 50, 100);
224 * pwm_apply_state(pwm, &state);
226 * This functions returns -EINVAL if @duty_cycle and/or @scale are
227 * inconsistent (@scale == 0 or @duty_cycle > @scale).
230 pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
233 if (!scale || duty_cycle > scale)
236 state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle *
244 * struct pwm_ops - PWM controller operations
245 * @request: optional hook for requesting a PWM
246 * @free: optional hook for freeing a PWM
247 * @capture: capture and report PWM signal
248 * @apply: atomically apply a new PWM config
249 * @get_state: get the current PWM state. This function is only
250 * called once per PWM device when the PWM chip is
252 * @owner: helps prevent removal of modules exporting active PWMs
253 * @config: configure duty cycles and period length for this PWM
254 * @set_polarity: configure the polarity of this PWM
255 * @enable: enable PWM output toggling
256 * @disable: disable PWM output toggling
259 int (*request)(struct pwm_chip *chip, struct pwm_device *pwm);
260 void (*free)(struct pwm_chip *chip, struct pwm_device *pwm);
261 int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
262 struct pwm_capture *result, unsigned long timeout);
263 int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
264 const struct pwm_state *state);
265 void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
266 struct pwm_state *state);
267 struct module *owner;
269 /* Only used by legacy drivers */
270 int (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
271 int duty_ns, int period_ns);
272 int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
273 enum pwm_polarity polarity);
274 int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
275 void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
279 * struct pwm_chip - abstract a PWM controller
280 * @dev: device providing the PWMs
281 * @ops: callbacks for this PWM controller
282 * @base: number of first PWM controlled by this chip
283 * @npwm: number of PWMs controlled by this chip
284 * @of_xlate: request a PWM device given a device tree PWM specifier
285 * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
286 * @list: list node for internal use
287 * @pwms: array of PWM devices allocated by the framework
291 const struct pwm_ops *ops;
295 struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
296 const struct of_phandle_args *args);
297 unsigned int of_pwm_n_cells;
299 /* only used internally by the PWM framework */
300 struct list_head list;
301 struct pwm_device *pwms;
305 * struct pwm_capture - PWM capture data
306 * @period: period of the PWM signal (in nanoseconds)
307 * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
311 unsigned int duty_cycle;
314 #if IS_ENABLED(CONFIG_PWM)
316 struct pwm_device *pwm_request(int pwm_id, const char *label);
317 void pwm_free(struct pwm_device *pwm);
318 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state);
319 int pwm_adjust_config(struct pwm_device *pwm);
322 * pwm_config() - change a PWM device configuration
324 * @duty_ns: "on" time (in nanoseconds)
325 * @period_ns: duration (in nanoseconds) of one cycle
327 * Returns: 0 on success or a negative error code on failure.
329 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
332 struct pwm_state state;
337 if (duty_ns < 0 || period_ns < 0)
340 pwm_get_state(pwm, &state);
341 if (state.duty_cycle == duty_ns && state.period == period_ns)
344 state.duty_cycle = duty_ns;
345 state.period = period_ns;
346 return pwm_apply_state(pwm, &state);
350 * pwm_enable() - start a PWM output toggling
353 * Returns: 0 on success or a negative error code on failure.
355 static inline int pwm_enable(struct pwm_device *pwm)
357 struct pwm_state state;
362 pwm_get_state(pwm, &state);
366 state.enabled = true;
367 return pwm_apply_state(pwm, &state);
371 * pwm_disable() - stop a PWM output toggling
374 static inline void pwm_disable(struct pwm_device *pwm)
376 struct pwm_state state;
381 pwm_get_state(pwm, &state);
385 state.enabled = false;
386 pwm_apply_state(pwm, &state);
389 /* PWM provider APIs */
390 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
391 unsigned long timeout);
392 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
393 void *pwm_get_chip_data(struct pwm_device *pwm);
395 int pwmchip_add_with_polarity(struct pwm_chip *chip,
396 enum pwm_polarity polarity);
397 int pwmchip_add(struct pwm_chip *chip);
398 int pwmchip_remove(struct pwm_chip *chip);
399 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
403 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
404 const struct of_phandle_args *args);
406 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
407 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
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 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
415 struct fwnode_handle *fwnode,
417 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
419 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
421 return ERR_PTR(-ENODEV);
424 static inline void pwm_free(struct pwm_device *pwm)
428 static inline int pwm_apply_state(struct pwm_device *pwm,
429 const struct pwm_state *state)
434 static inline int pwm_adjust_config(struct pwm_device *pwm)
439 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
445 static inline int pwm_capture(struct pwm_device *pwm,
446 struct pwm_capture *result,
447 unsigned long timeout)
452 static inline int pwm_enable(struct pwm_device *pwm)
457 static inline void pwm_disable(struct pwm_device *pwm)
461 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
466 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
471 static inline int pwmchip_add(struct pwm_chip *chip)
476 static inline int pwmchip_add_inversed(struct pwm_chip *chip)
481 static inline int pwmchip_remove(struct pwm_chip *chip)
486 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
490 return ERR_PTR(-ENODEV);
493 static inline struct pwm_device *pwm_get(struct device *dev,
494 const char *consumer)
496 return ERR_PTR(-ENODEV);
499 static inline struct pwm_device *of_pwm_get(struct device *dev,
500 struct device_node *np,
503 return ERR_PTR(-ENODEV);
506 static inline void pwm_put(struct pwm_device *pwm)
510 static inline struct pwm_device *devm_pwm_get(struct device *dev,
511 const char *consumer)
513 return ERR_PTR(-ENODEV);
516 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
517 struct device_node *np,
520 return ERR_PTR(-ENODEV);
523 static inline struct pwm_device *
524 devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode,
527 return ERR_PTR(-ENODEV);
530 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
535 static inline void pwm_apply_args(struct pwm_device *pwm)
537 struct pwm_state state = { };
540 * PWM users calling pwm_apply_args() expect to have a fresh config
541 * where the polarity and period are set according to pwm_args info.
542 * The problem is, polarity can only be changed when the PWM is
545 * PWM drivers supporting hardware readout may declare the PWM device
546 * as enabled, and prevent polarity setting, which changes from the
547 * existing behavior, where all PWM devices are declared as disabled
548 * at startup (even if they are actually enabled), thus authorizing
551 * To fulfill this requirement, we apply a new state which disables
552 * the PWM device and set the reference period and polarity config.
554 * Note that PWM users requiring a smooth handover between the
555 * bootloader and the kernel (like critical regulators controlled by
556 * PWM devices) will have to switch to the atomic API and avoid calling
560 state.enabled = false;
561 state.polarity = pwm->args.polarity;
562 state.period = pwm->args.period;
564 pwm_apply_state(pwm, &state);
568 struct list_head list;
569 const char *provider;
574 enum pwm_polarity polarity;
575 const char *module; /* optional, may be NULL */
578 #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \
579 _period, _polarity, _module) \
581 .provider = _provider, \
586 .polarity = _polarity, \
590 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
591 PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \
594 #if IS_ENABLED(CONFIG_PWM)
595 void pwm_add_table(struct pwm_lookup *table, size_t num);
596 void pwm_remove_table(struct pwm_lookup *table, size_t num);
598 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
602 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
607 #ifdef CONFIG_PWM_SYSFS
608 void pwmchip_sysfs_export(struct pwm_chip *chip);
609 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
611 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
615 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
618 #endif /* CONFIG_PWM_SYSFS */
620 #endif /* __LINUX_PWM_H */