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
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 * The returned PWM state represents the state that was applied by a previous call to
96 * pwm_apply_state(). Drivers may have to slightly tweak that state before programming it to
97 * hardware. If pwm_apply_state() was never called, this returns either the current hardware
98 * state (if supported) or the default settings.
100 static inline void pwm_get_state(const struct pwm_device *pwm,
101 struct pwm_state *state)
106 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
108 struct pwm_state state;
110 pwm_get_state(pwm, &state);
112 return state.enabled;
115 static inline void pwm_set_period(struct pwm_device *pwm, u64 period)
118 pwm->state.period = period;
121 static inline u64 pwm_get_period(const struct pwm_device *pwm)
123 struct pwm_state state;
125 pwm_get_state(pwm, &state);
130 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
133 pwm->state.duty_cycle = duty;
136 static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm)
138 struct pwm_state state;
140 pwm_get_state(pwm, &state);
142 return state.duty_cycle;
145 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
147 struct pwm_state state;
149 pwm_get_state(pwm, &state);
151 return state.polarity;
154 static inline void pwm_get_args(const struct pwm_device *pwm,
155 struct pwm_args *args)
161 * pwm_init_state() - prepare a new state to be applied with pwm_apply_state()
163 * @state: state to fill with the prepared PWM state
165 * This functions prepares a state that can later be tweaked and applied
166 * to the PWM device with pwm_apply_state(). This is a convenient function
167 * that first retrieves the current PWM state and the replaces the period
168 * and polarity fields with the reference values defined in pwm->args.
169 * Once the function returns, you can adjust the ->enabled and ->duty_cycle
170 * fields according to your needs before calling pwm_apply_state().
172 * ->duty_cycle is initially set to zero to avoid cases where the current
173 * ->duty_cycle value exceed the pwm_args->period one, which would trigger
174 * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle
177 static inline void pwm_init_state(const struct pwm_device *pwm,
178 struct pwm_state *state)
180 struct pwm_args args;
182 /* First get the current state. */
183 pwm_get_state(pwm, state);
185 /* Then fill it with the reference config */
186 pwm_get_args(pwm, &args);
188 state->period = args.period;
189 state->polarity = args.polarity;
190 state->duty_cycle = 0;
194 * pwm_get_relative_duty_cycle() - Get a relative duty cycle value
195 * @state: PWM state to extract the duty cycle from
196 * @scale: target scale of the relative duty cycle
198 * This functions converts the absolute duty cycle stored in @state (expressed
199 * in nanosecond) into a value relative to the period.
201 * For example if you want to get the duty_cycle expressed in percent, call:
203 * pwm_get_state(pwm, &state);
204 * duty = pwm_get_relative_duty_cycle(&state, 100);
206 static inline unsigned int
207 pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale)
212 return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale,
217 * pwm_set_relative_duty_cycle() - Set a relative duty cycle value
218 * @state: PWM state to fill
219 * @duty_cycle: relative duty cycle value
220 * @scale: scale in which @duty_cycle is expressed
222 * This functions converts a relative into an absolute duty cycle (expressed
223 * in nanoseconds), and puts the result in state->duty_cycle.
225 * For example if you want to configure a 50% duty cycle, call:
227 * pwm_init_state(pwm, &state);
228 * pwm_set_relative_duty_cycle(&state, 50, 100);
229 * pwm_apply_state(pwm, &state);
231 * This functions returns -EINVAL if @duty_cycle and/or @scale are
232 * inconsistent (@scale == 0 or @duty_cycle > @scale).
235 pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
238 if (!scale || duty_cycle > scale)
241 state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle *
249 * struct pwm_ops - PWM controller operations
250 * @request: optional hook for requesting a PWM
251 * @free: optional hook for freeing a PWM
252 * @capture: capture and report PWM signal
253 * @apply: atomically apply a new PWM config
254 * @get_state: get the current PWM state. This function is only
255 * called once per PWM device when the PWM chip is
257 * @owner: helps prevent removal of modules exporting active PWMs
258 * @config: configure duty cycles and period length for this PWM
259 * @set_polarity: configure the polarity of this PWM
260 * @enable: enable PWM output toggling
261 * @disable: disable PWM output toggling
264 int (*request)(struct pwm_chip *chip, struct pwm_device *pwm);
265 void (*free)(struct pwm_chip *chip, struct pwm_device *pwm);
266 int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
267 struct pwm_capture *result, unsigned long timeout);
268 int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
269 const struct pwm_state *state);
270 void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
271 struct pwm_state *state);
272 struct module *owner;
274 /* Only used by legacy drivers */
275 int (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
276 int duty_ns, int period_ns);
277 int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
278 enum pwm_polarity polarity);
279 int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
280 void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
284 * struct pwm_chip - abstract a PWM controller
285 * @dev: device providing the PWMs
286 * @ops: callbacks for this PWM controller
287 * @base: number of first PWM controlled by this chip
288 * @npwm: number of PWMs controlled by this chip
289 * @of_xlate: request a PWM device given a device tree PWM specifier
290 * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
291 * @list: list node for internal use
292 * @pwms: array of PWM devices allocated by the framework
296 const struct pwm_ops *ops;
300 struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
301 const struct of_phandle_args *args);
302 unsigned int of_pwm_n_cells;
304 /* only used internally by the PWM framework */
305 struct list_head list;
306 struct pwm_device *pwms;
310 * struct pwm_capture - PWM capture data
311 * @period: period of the PWM signal (in nanoseconds)
312 * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
316 unsigned int duty_cycle;
319 #if IS_ENABLED(CONFIG_PWM)
321 struct pwm_device *pwm_request(int pwm_id, const char *label);
322 void pwm_free(struct pwm_device *pwm);
323 int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state);
324 int pwm_adjust_config(struct pwm_device *pwm);
327 * pwm_config() - change a PWM device configuration
329 * @duty_ns: "on" time (in nanoseconds)
330 * @period_ns: duration (in nanoseconds) of one cycle
332 * Returns: 0 on success or a negative error code on failure.
334 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
337 struct pwm_state state;
342 if (duty_ns < 0 || period_ns < 0)
345 pwm_get_state(pwm, &state);
346 if (state.duty_cycle == duty_ns && state.period == period_ns)
349 state.duty_cycle = duty_ns;
350 state.period = period_ns;
351 return pwm_apply_state(pwm, &state);
355 * pwm_enable() - start a PWM output toggling
358 * Returns: 0 on success or a negative error code on failure.
360 static inline int pwm_enable(struct pwm_device *pwm)
362 struct pwm_state state;
367 pwm_get_state(pwm, &state);
371 state.enabled = true;
372 return pwm_apply_state(pwm, &state);
376 * pwm_disable() - stop a PWM output toggling
379 static inline void pwm_disable(struct pwm_device *pwm)
381 struct pwm_state state;
386 pwm_get_state(pwm, &state);
390 state.enabled = false;
391 pwm_apply_state(pwm, &state);
394 /* PWM provider APIs */
395 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
396 unsigned long timeout);
397 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
398 void *pwm_get_chip_data(struct pwm_device *pwm);
400 int pwmchip_add(struct pwm_chip *chip);
401 int pwmchip_remove(struct pwm_chip *chip);
402 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
406 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
407 const struct of_phandle_args *args);
409 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
410 struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
412 void pwm_put(struct pwm_device *pwm);
414 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
415 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
417 struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
418 struct fwnode_handle *fwnode,
420 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
422 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
424 return ERR_PTR(-ENODEV);
427 static inline void pwm_free(struct pwm_device *pwm)
431 static inline int pwm_apply_state(struct pwm_device *pwm,
432 const struct pwm_state *state)
437 static inline int pwm_adjust_config(struct pwm_device *pwm)
442 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
448 static inline int pwm_capture(struct pwm_device *pwm,
449 struct pwm_capture *result,
450 unsigned long timeout)
455 static inline int pwm_enable(struct pwm_device *pwm)
460 static inline void pwm_disable(struct pwm_device *pwm)
464 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
469 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
474 static inline int pwmchip_add(struct pwm_chip *chip)
479 static inline int pwmchip_remove(struct pwm_chip *chip)
484 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
488 return ERR_PTR(-ENODEV);
491 static inline struct pwm_device *pwm_get(struct device *dev,
492 const char *consumer)
494 return ERR_PTR(-ENODEV);
497 static inline struct pwm_device *of_pwm_get(struct device *dev,
498 struct device_node *np,
501 return ERR_PTR(-ENODEV);
504 static inline void pwm_put(struct pwm_device *pwm)
508 static inline struct pwm_device *devm_pwm_get(struct device *dev,
509 const char *consumer)
511 return ERR_PTR(-ENODEV);
514 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
515 struct device_node *np,
518 return ERR_PTR(-ENODEV);
521 static inline struct pwm_device *
522 devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode,
525 return ERR_PTR(-ENODEV);
528 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
533 static inline void pwm_apply_args(struct pwm_device *pwm)
535 struct pwm_state state = { };
538 * PWM users calling pwm_apply_args() expect to have a fresh config
539 * where the polarity and period are set according to pwm_args info.
540 * The problem is, polarity can only be changed when the PWM is
543 * PWM drivers supporting hardware readout may declare the PWM device
544 * as enabled, and prevent polarity setting, which changes from the
545 * existing behavior, where all PWM devices are declared as disabled
546 * at startup (even if they are actually enabled), thus authorizing
549 * To fulfill this requirement, we apply a new state which disables
550 * the PWM device and set the reference period and polarity config.
552 * Note that PWM users requiring a smooth handover between the
553 * bootloader and the kernel (like critical regulators controlled by
554 * PWM devices) will have to switch to the atomic API and avoid calling
558 state.enabled = false;
559 state.polarity = pwm->args.polarity;
560 state.period = pwm->args.period;
562 pwm_apply_state(pwm, &state);
566 struct list_head list;
567 const char *provider;
572 enum pwm_polarity polarity;
573 const char *module; /* optional, may be NULL */
576 #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \
577 _period, _polarity, _module) \
579 .provider = _provider, \
584 .polarity = _polarity, \
588 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
589 PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \
592 #if IS_ENABLED(CONFIG_PWM)
593 void pwm_add_table(struct pwm_lookup *table, size_t num);
594 void pwm_remove_table(struct pwm_lookup *table, size_t num);
596 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
600 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
605 #ifdef CONFIG_PWM_SYSFS
606 void pwmchip_sysfs_export(struct pwm_chip *chip);
607 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
609 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
613 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
616 #endif /* CONFIG_PWM_SYSFS */
618 #endif /* __LINUX_PWM_H */