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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - include/linux/pwm.h
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 pwm_get_state(pwm
, &state
);
239 if (state
.duty_cycle
== duty_ns
&& state
.period
== period_ns
)
242 state
.duty_cycle
= duty_ns
;
243 state
.period
= period_ns
;
244 return pwm_apply_state(pwm
, &state
);
248 * pwm_set_polarity() - configure the polarity of a PWM signal
250 * @polarity: new polarity of the PWM signal
252 * Note that the polarity cannot be configured while the PWM device is
255 * Returns: 0 on success or a negative error code on failure.
257 static inline int pwm_set_polarity(struct pwm_device
*pwm
,
258 enum pwm_polarity polarity
)
260 struct pwm_state state
;
265 pwm_get_state(pwm
, &state
);
266 if (state
.polarity
== polarity
)
270 * Changing the polarity of a running PWM without adjusting the
271 * dutycycle/period value is a bit risky (can introduce glitches).
272 * Return -EBUSY in this case.
273 * Note that this is allowed when using pwm_apply_state() because
274 * the user specifies all the parameters.
279 state
.polarity
= polarity
;
280 return pwm_apply_state(pwm
, &state
);
284 * pwm_enable() - start a PWM output toggling
287 * Returns: 0 on success or a negative error code on failure.
289 static inline int pwm_enable(struct pwm_device
*pwm
)
291 struct pwm_state state
;
296 pwm_get_state(pwm
, &state
);
300 state
.enabled
= true;
301 return pwm_apply_state(pwm
, &state
);
305 * pwm_disable() - stop a PWM output toggling
308 static inline void pwm_disable(struct pwm_device
*pwm
)
310 struct pwm_state state
;
315 pwm_get_state(pwm
, &state
);
319 state
.enabled
= false;
320 pwm_apply_state(pwm
, &state
);
324 /* PWM provider APIs */
325 int pwm_set_chip_data(struct pwm_device
*pwm
, void *data
);
326 void *pwm_get_chip_data(struct pwm_device
*pwm
);
328 int pwmchip_add_with_polarity(struct pwm_chip
*chip
,
329 enum pwm_polarity polarity
);
330 int pwmchip_add(struct pwm_chip
*chip
);
331 int pwmchip_remove(struct pwm_chip
*chip
);
332 struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
336 struct pwm_device
*of_pwm_xlate_with_flags(struct pwm_chip
*pc
,
337 const struct of_phandle_args
*args
);
339 struct pwm_device
*pwm_get(struct device
*dev
, const char *con_id
);
340 struct pwm_device
*of_pwm_get(struct device_node
*np
, const char *con_id
);
341 void pwm_put(struct pwm_device
*pwm
);
343 struct pwm_device
*devm_pwm_get(struct device
*dev
, const char *con_id
);
344 struct pwm_device
*devm_of_pwm_get(struct device
*dev
, struct device_node
*np
,
346 void devm_pwm_put(struct device
*dev
, struct pwm_device
*pwm
);
348 bool pwm_can_sleep(struct pwm_device
*pwm
);
350 static inline struct pwm_device
*pwm_request(int pwm_id
, const char *label
)
352 return ERR_PTR(-ENODEV
);
355 static inline void pwm_free(struct pwm_device
*pwm
)
359 static inline int pwm_apply_state(struct pwm_device
*pwm
,
360 const struct pwm_state
*state
)
365 static inline int pwm_adjust_config(struct pwm_device
*pwm
)
370 static inline int pwm_config(struct pwm_device
*pwm
, int duty_ns
,
376 static inline int pwm_set_polarity(struct pwm_device
*pwm
,
377 enum pwm_polarity polarity
)
382 static inline int pwm_enable(struct pwm_device
*pwm
)
387 static inline void pwm_disable(struct pwm_device
*pwm
)
391 static inline int pwm_set_chip_data(struct pwm_device
*pwm
, void *data
)
396 static inline void *pwm_get_chip_data(struct pwm_device
*pwm
)
401 static inline int pwmchip_add(struct pwm_chip
*chip
)
406 static inline int pwmchip_add_inversed(struct pwm_chip
*chip
)
411 static inline int pwmchip_remove(struct pwm_chip
*chip
)
416 static inline struct pwm_device
*pwm_request_from_chip(struct pwm_chip
*chip
,
420 return ERR_PTR(-ENODEV
);
423 static inline struct pwm_device
*pwm_get(struct device
*dev
,
424 const char *consumer
)
426 return ERR_PTR(-ENODEV
);
429 static inline struct pwm_device
*of_pwm_get(struct device_node
*np
,
432 return ERR_PTR(-ENODEV
);
435 static inline void pwm_put(struct pwm_device
*pwm
)
439 static inline struct pwm_device
*devm_pwm_get(struct device
*dev
,
440 const char *consumer
)
442 return ERR_PTR(-ENODEV
);
445 static inline struct pwm_device
*devm_of_pwm_get(struct device
*dev
,
446 struct device_node
*np
,
449 return ERR_PTR(-ENODEV
);
452 static inline void devm_pwm_put(struct device
*dev
, struct pwm_device
*pwm
)
456 static inline bool pwm_can_sleep(struct pwm_device
*pwm
)
462 static inline void pwm_apply_args(struct pwm_device
*pwm
)
465 * PWM users calling pwm_apply_args() expect to have a fresh config
466 * where the polarity and period are set according to pwm_args info.
467 * The problem is, polarity can only be changed when the PWM is
470 * PWM drivers supporting hardware readout may declare the PWM device
471 * as enabled, and prevent polarity setting, which changes from the
472 * existing behavior, where all PWM devices are declared as disabled
473 * at startup (even if they are actually enabled), thus authorizing
476 * Instead of setting ->enabled to false, we call pwm_disable()
477 * before pwm_set_polarity() to ensure that everything is configured
478 * as expected, and the PWM is really disabled when the user request
481 * Note that PWM users requiring a smooth handover between the
482 * bootloader and the kernel (like critical regulators controlled by
483 * PWM devices) will have to switch to the atomic API and avoid calling
487 pwm_set_polarity(pwm
, pwm
->args
.polarity
);
491 struct list_head list
;
492 const char *provider
;
497 enum pwm_polarity polarity
;
500 #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \
502 .provider = _provider, \
507 .polarity = _polarity \
510 #if IS_ENABLED(CONFIG_PWM)
511 void pwm_add_table(struct pwm_lookup
*table
, size_t num
);
512 void pwm_remove_table(struct pwm_lookup
*table
, size_t num
);
514 static inline void pwm_add_table(struct pwm_lookup
*table
, size_t num
)
518 static inline void pwm_remove_table(struct pwm_lookup
*table
, size_t num
)
523 #ifdef CONFIG_PWM_SYSFS
524 void pwmchip_sysfs_export(struct pwm_chip
*chip
);
525 void pwmchip_sysfs_unexport(struct pwm_chip
*chip
);
527 static inline void pwmchip_sysfs_export(struct pwm_chip
*chip
)
531 static inline void pwmchip_sysfs_unexport(struct pwm_chip
*chip
)
534 #endif /* CONFIG_PWM_SYSFS */
536 #endif /* __LINUX_PWM_H */