/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __LINUX_PWM_H #define __LINUX_PWM_H #include <linux/device.h> #include <linux/err.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> MODULE_IMPORT_NS(…); struct pwm_chip; /** * enum pwm_polarity - polarity of a PWM signal * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- * cycle, followed by a low signal for the remainder of the pulse * period * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- * cycle, followed by a high signal for the remainder of the pulse * period */ enum pwm_polarity { … }; /** * struct pwm_args - board-dependent PWM arguments * @period: reference period * @polarity: reference polarity * * This structure describes board-dependent arguments attached to a PWM * device. These arguments are usually retrieved from the PWM lookup table or * device tree. * * Do not confuse this with the PWM state: PWM arguments represent the initial * configuration that users want to use on this PWM device rather than the * current PWM hardware state. */ struct pwm_args { … }; enum { … }; /* * struct pwm_state - state of a PWM channel * @period: PWM period (in nanoseconds) * @duty_cycle: PWM duty cycle (in nanoseconds) * @polarity: PWM polarity * @enabled: PWM enabled status * @usage_power: If set, the PWM driver is only required to maintain the power * output but has more freedom regarding signal form. * If supported, the signal can be optimized, for example to * improve EMI by phase shifting individual channels. */ struct pwm_state { … }; /** * struct pwm_device - PWM channel object * @label: name of the PWM device * @flags: flags associated with the PWM device * @hwpwm: per-chip relative index of the PWM device * @chip: PWM chip providing this PWM device * @args: PWM arguments * @state: last applied state * @last: last implemented state (for PWM_DEBUG) */ struct pwm_device { … }; /** * pwm_get_state() - retrieve the current PWM state * @pwm: PWM device * @state: state to fill with the current PWM state * * The returned PWM state represents the state that was applied by a previous call to * pwm_apply_might_sleep(). Drivers may have to slightly tweak that state before programming it to * hardware. If pwm_apply_might_sleep() was never called, this returns either the current hardware * state (if supported) or the default settings. */ static inline void pwm_get_state(const struct pwm_device *pwm, struct pwm_state *state) { … } static inline bool pwm_is_enabled(const struct pwm_device *pwm) { … } static inline u64 pwm_get_period(const struct pwm_device *pwm) { … } static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm) { … } static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) { … } static inline void pwm_get_args(const struct pwm_device *pwm, struct pwm_args *args) { … } /** * pwm_init_state() - prepare a new state to be applied with pwm_apply_might_sleep() * @pwm: PWM device * @state: state to fill with the prepared PWM state * * This functions prepares a state that can later be tweaked and applied * to the PWM device with pwm_apply_might_sleep(). This is a convenient function * that first retrieves the current PWM state and the replaces the period * and polarity fields with the reference values defined in pwm->args. * Once the function returns, you can adjust the ->enabled and ->duty_cycle * fields according to your needs before calling pwm_apply_might_sleep(). * * ->duty_cycle is initially set to zero to avoid cases where the current * ->duty_cycle value exceed the pwm_args->period one, which would trigger * an error if the user calls pwm_apply_might_sleep() without adjusting ->duty_cycle * first. */ static inline void pwm_init_state(const struct pwm_device *pwm, struct pwm_state *state) { … } /** * pwm_get_relative_duty_cycle() - Get a relative duty cycle value * @state: PWM state to extract the duty cycle from * @scale: target scale of the relative duty cycle * * This functions converts the absolute duty cycle stored in @state (expressed * in nanosecond) into a value relative to the period. * * For example if you want to get the duty_cycle expressed in percent, call: * * pwm_get_state(pwm, &state); * duty = pwm_get_relative_duty_cycle(&state, 100); */ static inline unsigned int pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) { … } /** * pwm_set_relative_duty_cycle() - Set a relative duty cycle value * @state: PWM state to fill * @duty_cycle: relative duty cycle value * @scale: scale in which @duty_cycle is expressed * * This functions converts a relative into an absolute duty cycle (expressed * in nanoseconds), and puts the result in state->duty_cycle. * * For example if you want to configure a 50% duty cycle, call: * * pwm_init_state(pwm, &state); * pwm_set_relative_duty_cycle(&state, 50, 100); * pwm_apply_might_sleep(pwm, &state); * * This functions returns -EINVAL if @duty_cycle and/or @scale are * inconsistent (@scale == 0 or @duty_cycle > @scale). */ static inline int pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, unsigned int scale) { … } /** * struct pwm_capture - PWM capture data * @period: period of the PWM signal (in nanoseconds) * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) */ struct pwm_capture { … }; /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM * @free: optional hook for freeing a PWM * @capture: capture and report PWM signal * @apply: atomically apply a new PWM config * @get_state: get the current PWM state. */ struct pwm_ops { … }; /** * struct pwm_chip - abstract a PWM controller * @dev: device providing the PWMs * @ops: callbacks for this PWM controller * @owner: module providing this chip * @id: unique number of this PWM chip * @npwm: number of PWMs controlled by this chip * @of_xlate: request a PWM device given a device tree PWM specifier * @atomic: can the driver's ->apply() be called in atomic context * @uses_pwmchip_alloc: signals if pwmchip_allow was used to allocate this chip * @pwms: array of PWM devices allocated by the framework */ struct pwm_chip { … }; static inline struct device *pwmchip_parent(const struct pwm_chip *chip) { … } static inline void *pwmchip_get_drvdata(struct pwm_chip *chip) { … } static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data) { … } #if IS_ENABLED(CONFIG_PWM) /* PWM user APIs */ int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state); int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state); int pwm_adjust_config(struct pwm_device *pwm); /** * pwm_config() - change a PWM device configuration * @pwm: PWM device * @duty_ns: "on" time (in nanoseconds) * @period_ns: duration (in nanoseconds) of one cycle * * Returns: 0 on success or a negative error code on failure. */ static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) { … } /** * pwm_enable() - start a PWM output toggling * @pwm: PWM device * * Returns: 0 on success or a negative error code on failure. */ static inline int pwm_enable(struct pwm_device *pwm) { … } /** * pwm_disable() - stop a PWM output toggling * @pwm: PWM device */ static inline void pwm_disable(struct pwm_device *pwm) { … } /** * pwm_might_sleep() - is pwm_apply_atomic() supported? * @pwm: PWM device * * Returns: false if pwm_apply_atomic() can be called from atomic context. */ static inline bool pwm_might_sleep(struct pwm_device *pwm) { … } /* PWM provider APIs */ void pwmchip_put(struct pwm_chip *chip); struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv); int __pwmchip_add(struct pwm_chip *chip, struct module *owner); #define pwmchip_add(chip) … void pwmchip_remove(struct pwm_chip *chip); int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner); #define devm_pwmchip_add(dev, chip) … struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args); struct pwm_device *of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args); struct pwm_device *pwm_get(struct device *dev, const char *con_id); void pwm_put(struct pwm_device *pwm); struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); struct pwm_device *devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, const char *con_id); #else static inline bool pwm_might_sleep(struct pwm_device *pwm) { return true; } static inline int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state) { might_sleep(); return -EOPNOTSUPP; } static inline int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state) { return -EOPNOTSUPP; } static inline int pwm_adjust_config(struct pwm_device *pwm) { return -EOPNOTSUPP; } static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) { might_sleep(); return -EINVAL; } static inline int pwm_enable(struct pwm_device *pwm) { might_sleep(); return -EINVAL; } static inline void pwm_disable(struct pwm_device *pwm) { might_sleep(); } static inline void pwmchip_put(struct pwm_chip *chip) { } static inline struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) { return ERR_PTR(-EINVAL); } static inline struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv) { return pwmchip_alloc(parent, npwm, sizeof_priv); } static inline int pwmchip_add(struct pwm_chip *chip) { return -EINVAL; } static inline int pwmchip_remove(struct pwm_chip *chip) { return -EINVAL; } static inline int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip) { return -EINVAL; } static inline struct pwm_device *pwm_get(struct device *dev, const char *consumer) { might_sleep(); return ERR_PTR(-ENODEV); } static inline void pwm_put(struct pwm_device *pwm) { might_sleep(); } static inline struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer) { might_sleep(); return ERR_PTR(-ENODEV); } static inline struct pwm_device * devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, const char *con_id) { might_sleep(); return ERR_PTR(-ENODEV); } #endif static inline void pwm_apply_args(struct pwm_device *pwm) { … } struct pwm_lookup { … }; #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ _period, _polarity, _module) … #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) … #if IS_ENABLED(CONFIG_PWM) void pwm_add_table(struct pwm_lookup *table, size_t num); void pwm_remove_table(struct pwm_lookup *table, size_t num); #else static inline void pwm_add_table(struct pwm_lookup *table, size_t num) { } static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) { } #endif #endif /* __LINUX_PWM_H */
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