5 #include <linux/mutex.h>
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
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
22 PWM_POLARITY_INVERSED,
26 * struct pwm_args - board-dependent PWM arguments
27 * @period: reference period
28 * @polarity: reference polarity
30 * This structure describes board-dependent arguments attached to a PWM
31 * device. These arguments are usually retrieved from the PWM lookup table or
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.
40 enum pwm_polarity polarity;
44 PWMF_REQUESTED = 1 << 0,
45 PWMF_EXPORTED = 1 << 1,
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
57 unsigned int duty_cycle;
58 enum pwm_polarity polarity;
63 * struct pwm_device - PWM channel object
64 * @label: name of the PWM device
65 * @flags: flags associated with the PWM device
66 * @hwpwm: per-chip relative index of the PWM device
67 * @pwm: global index of the PWM device
68 * @chip: PWM chip providing this PWM device
69 * @chip_data: chip-private data associated with the PWM device
70 * @args: PWM arguments
71 * @state: curent PWM channel state
78 struct pwm_chip *chip;
82 struct pwm_state state;
86 * pwm_get_state() - retrieve the current PWM state
88 * @state: state to fill with the current PWM state
90 static inline void pwm_get_state(const struct pwm_device *pwm,
91 struct pwm_state *state)
96 static inline bool pwm_is_enabled(const struct pwm_device *pwm)
98 struct pwm_state state;
100 pwm_get_state(pwm, &state);
102 return state.enabled;
105 static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
108 pwm->state.period = period;
111 static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
113 struct pwm_state state;
115 pwm_get_state(pwm, &state);
120 static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
123 pwm->state.duty_cycle = duty;
126 static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
128 struct pwm_state state;
130 pwm_get_state(pwm, &state);
132 return state.duty_cycle;
135 static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
137 struct pwm_state state;
139 pwm_get_state(pwm, &state);
141 return state.polarity;
144 static inline void pwm_get_args(const struct pwm_device *pwm,
145 struct pwm_args *args)
151 * struct pwm_ops - PWM controller operations
152 * @request: optional hook for requesting a PWM
153 * @free: optional hook for freeing a PWM
154 * @config: configure duty cycles and period length for this PWM
155 * @set_polarity: configure the polarity of this PWM
156 * @enable: enable PWM output toggling
157 * @disable: disable PWM output toggling
158 * @apply: atomically apply a new PWM config. The state argument
159 * should be adjusted with the real hardware config (if the
160 * approximate the period or duty_cycle value, state should
162 * @get_state: get the current PWM state. This function is only
163 * called once per PWM device when the PWM chip is
165 * @dbg_show: optional routine to show contents in debugfs
166 * @owner: helps prevent removal of modules exporting active PWMs
169 int (*request)(struct pwm_chip *chip, struct pwm_device *pwm);
170 void (*free)(struct pwm_chip *chip, struct pwm_device *pwm);
171 int (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
172 int duty_ns, int period_ns);
173 int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
174 enum pwm_polarity polarity);
175 int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
176 void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
177 int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
178 struct pwm_state *state);
179 void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
180 struct pwm_state *state);
181 #ifdef CONFIG_DEBUG_FS
182 void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
184 struct module *owner;
188 * struct pwm_chip - abstract a PWM controller
189 * @dev: device providing the PWMs
190 * @list: list node for internal use
191 * @ops: callbacks for this PWM controller
192 * @base: number of first PWM controlled by this chip
193 * @npwm: number of PWMs controlled by this chip
194 * @pwms: array of PWM devices allocated by the framework
195 * @of_xlate: request a PWM device given a device tree PWM specifier
196 * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
197 * @can_sleep: must be true if the .config(), .enable() or .disable()
198 * operations may sleep
202 struct list_head list;
203 const struct pwm_ops *ops;
207 struct pwm_device *pwms;
209 struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
210 const struct of_phandle_args *args);
211 unsigned int of_pwm_n_cells;
215 #if IS_ENABLED(CONFIG_PWM)
217 struct pwm_device *pwm_request(int pwm_id, const char *label);
218 void pwm_free(struct pwm_device *pwm);
219 int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
220 int pwm_adjust_config(struct pwm_device *pwm);
223 * pwm_config() - change a PWM device configuration
225 * @duty_ns: "on" time (in nanoseconds)
226 * @period_ns: duration (in nanoseconds) of one cycle
228 * Returns: 0 on success or a negative error code on failure.
230 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
233 struct pwm_state state;
238 if (duty_ns < 0 || period_ns < 0)
241 pwm_get_state(pwm, &state);
242 if (state.duty_cycle == duty_ns && state.period == period_ns)
245 state.duty_cycle = duty_ns;
246 state.period = period_ns;
247 return pwm_apply_state(pwm, &state);
251 * pwm_set_polarity() - configure the polarity of a PWM signal
253 * @polarity: new polarity of the PWM signal
255 * Note that the polarity cannot be configured while the PWM device is
258 * Returns: 0 on success or a negative error code on failure.
260 static inline int pwm_set_polarity(struct pwm_device *pwm,
261 enum pwm_polarity polarity)
263 struct pwm_state state;
268 pwm_get_state(pwm, &state);
269 if (state.polarity == polarity)
273 * Changing the polarity of a running PWM without adjusting the
274 * dutycycle/period value is a bit risky (can introduce glitches).
275 * Return -EBUSY in this case.
276 * Note that this is allowed when using pwm_apply_state() because
277 * the user specifies all the parameters.
282 state.polarity = polarity;
283 return pwm_apply_state(pwm, &state);
287 * pwm_enable() - start a PWM output toggling
290 * Returns: 0 on success or a negative error code on failure.
292 static inline int pwm_enable(struct pwm_device *pwm)
294 struct pwm_state state;
299 pwm_get_state(pwm, &state);
303 state.enabled = true;
304 return pwm_apply_state(pwm, &state);
308 * pwm_disable() - stop a PWM output toggling
311 static inline void pwm_disable(struct pwm_device *pwm)
313 struct pwm_state state;
318 pwm_get_state(pwm, &state);
322 state.enabled = false;
323 pwm_apply_state(pwm, &state);
327 /* PWM provider APIs */
328 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
329 void *pwm_get_chip_data(struct pwm_device *pwm);
331 int pwmchip_add_with_polarity(struct pwm_chip *chip,
332 enum pwm_polarity polarity);
333 int pwmchip_add(struct pwm_chip *chip);
334 int pwmchip_remove(struct pwm_chip *chip);
335 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
339 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
340 const struct of_phandle_args *args);
342 struct pwm_device *pwm_get(struct device *dev, const char *con_id);
343 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
344 void pwm_put(struct pwm_device *pwm);
346 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
347 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
349 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
351 bool pwm_can_sleep(struct pwm_device *pwm);
353 static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
355 return ERR_PTR(-ENODEV);
358 static inline void pwm_free(struct pwm_device *pwm)
362 static inline int pwm_apply_state(struct pwm_device *pwm,
363 const struct pwm_state *state)
368 static inline int pwm_adjust_config(struct pwm_device *pwm)
373 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
379 static inline int pwm_set_polarity(struct pwm_device *pwm,
380 enum pwm_polarity polarity)
385 static inline int pwm_enable(struct pwm_device *pwm)
390 static inline void pwm_disable(struct pwm_device *pwm)
394 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
399 static inline void *pwm_get_chip_data(struct pwm_device *pwm)
404 static inline int pwmchip_add(struct pwm_chip *chip)
409 static inline int pwmchip_add_inversed(struct pwm_chip *chip)
414 static inline int pwmchip_remove(struct pwm_chip *chip)
419 static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
423 return ERR_PTR(-ENODEV);
426 static inline struct pwm_device *pwm_get(struct device *dev,
427 const char *consumer)
429 return ERR_PTR(-ENODEV);
432 static inline struct pwm_device *of_pwm_get(struct device_node *np,
435 return ERR_PTR(-ENODEV);
438 static inline void pwm_put(struct pwm_device *pwm)
442 static inline struct pwm_device *devm_pwm_get(struct device *dev,
443 const char *consumer)
445 return ERR_PTR(-ENODEV);
448 static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
449 struct device_node *np,
452 return ERR_PTR(-ENODEV);
455 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
459 static inline bool pwm_can_sleep(struct pwm_device *pwm)
465 static inline void pwm_apply_args(struct pwm_device *pwm)
467 struct pwm_state state = { };
470 * PWM users calling pwm_apply_args() expect to have a fresh config
471 * where the polarity and period are set according to pwm_args info.
472 * The problem is, polarity can only be changed when the PWM is
475 * PWM drivers supporting hardware readout may declare the PWM device
476 * as enabled, and prevent polarity setting, which changes from the
477 * existing behavior, where all PWM devices are declared as disabled
478 * at startup (even if they are actually enabled), thus authorizing
481 * To fulfill this requirement, we apply a new state which disables
482 * the PWM device and set the reference period and polarity config.
484 * Note that PWM users requiring a smooth handover between the
485 * bootloader and the kernel (like critical regulators controlled by
486 * PWM devices) will have to switch to the atomic API and avoid calling
490 state.enabled = false;
491 state.polarity = pwm->args.polarity;
492 state.period = pwm->args.period;
494 pwm_apply_state(pwm, &state);
498 struct list_head list;
499 const char *provider;
504 enum pwm_polarity polarity;
507 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
509 .provider = _provider, \
514 .polarity = _polarity \
517 #if IS_ENABLED(CONFIG_PWM)
518 void pwm_add_table(struct pwm_lookup *table, size_t num);
519 void pwm_remove_table(struct pwm_lookup *table, size_t num);
521 static inline void pwm_add_table(struct pwm_lookup *table, size_t num)
525 static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
530 #ifdef CONFIG_PWM_SYSFS
531 void pwmchip_sysfs_export(struct pwm_chip *chip);
532 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
534 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
538 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
541 #endif /* CONFIG_PWM_SYSFS */
543 #endif /* __LINUX_PWM_H */