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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 */