/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __LINUX_PWM_H #define __LINUX_PWM_H #include <linux/err.h> #include <linux/mutex.h> #include <linux/of.h> struct pwm_capture; struct seq_file; 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 { PWM_POLARITY_NORMAL, PWM_POLARITY_INVERSED, }; /** * 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 { unsigned int period; enum pwm_polarity polarity; }; enum { PWMF_REQUESTED = 1 << 0, PWMF_EXPORTED = 1 << 1, }; /* * 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 */ struct pwm_state { unsigned int period; unsigned int duty_cycle; enum pwm_polarity polarity; bool enabled; }; /** * 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 * @pwm: global index of the PWM device * @chip: PWM chip providing this PWM device * @chip_data: chip-private data associated with the PWM device * @args: PWM arguments * @state: curent PWM channel state */ struct pwm_device { const char *label; unsigned long flags; unsigned int hwpwm; unsigned int pwm; struct pwm_chip *chip; void *chip_data; struct pwm_args args; struct pwm_state state; }; /** * pwm_get_state() - retrieve the current PWM state * @pwm: PWM device * @state: state to fill with the current PWM state */ static inline void pwm_get_state(const struct pwm_device *pwm, struct pwm_state *state) { *state = pwm->state; } static inline bool pwm_is_enabled(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); return state.enabled; } static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period) { if (pwm) pwm->state.period = period; } static inline unsigned int pwm_get_period(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); return state.period; } static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty) { if (pwm) pwm->state.duty_cycle = duty; } static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); return state.duty_cycle; } static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) { struct pwm_state state; pwm_get_state(pwm, &state); return state.polarity; } static inline void pwm_get_args(const struct pwm_device *pwm, struct pwm_args *args) { *args = pwm->args; } /** * pwm_init_state() - prepare a new state to be applied with pwm_apply_state() * @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_state(). 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_state(). * * ->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_state() without adjusting ->duty_cycle * first. */ static inline void pwm_init_state(const struct pwm_device *pwm, struct pwm_state *state) { struct pwm_args args; /* First get the current state. */ pwm_get_state(pwm, state); /* Then fill it with the reference config */ pwm_get_args(pwm, &args); state->period = args.period; state->polarity = args.polarity; state->duty_cycle = 0; } /** * 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) { if (!state->period) return 0; return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, state->period); } /** * 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_state(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) { if (!scale || duty_cycle > scale) return -EINVAL; state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * state->period, scale); return 0; } /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM * @free: optional hook for freeing a PWM * @config: configure duty cycles and period length for this PWM * @set_polarity: configure the polarity of this PWM * @capture: capture and report PWM signal * @enable: enable PWM output toggling * @disable: disable PWM output toggling * @apply: atomically apply a new PWM config. The state argument * should be adjusted with the real hardware config (if the * approximate the period or duty_cycle value, state should * reflect it) * @get_state: get the current PWM state. This function is only * called once per PWM device when the PWM chip is * registered. * @dbg_show: optional routine to show contents in debugfs * @owner: helps prevent removal of modules exporting active PWMs */ struct pwm_ops { int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); int (*config)(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns); int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity); int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_capture *result, unsigned long timeout); int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state); void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state); #ifdef CONFIG_DEBUG_FS void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s); #endif struct module *owner; }; /** * struct pwm_chip - abstract a PWM controller * @dev: device providing the PWMs * @list: list node for internal use * @ops: callbacks for this PWM controller * @base: number of first PWM controlled by this chip * @npwm: number of PWMs controlled by this chip * @pwms: array of PWM devices allocated by the framework * @of_xlate: request a PWM device given a device tree PWM specifier * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier */ struct pwm_chip { struct device *dev; struct list_head list; const struct pwm_ops *ops; int base; unsigned int npwm; struct pwm_device *pwms; struct pwm_device * (*of_xlate)(struct pwm_chip *pc, const struct of_phandle_args *args); unsigned int of_pwm_n_cells; }; /** * 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 { unsigned int period; unsigned int duty_cycle; }; #if IS_ENABLED(CONFIG_PWM) /* PWM user APIs */ struct pwm_device *pwm_request(int pwm_id, const char *label); void pwm_free(struct pwm_device *pwm); int pwm_apply_state(struct pwm_device *pwm, 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) { struct pwm_state state; if (!pwm) return -EINVAL; if (duty_ns < 0 || period_ns < 0) return -EINVAL; pwm_get_state(pwm, &state); if (state.duty_cycle == duty_ns && state.period == period_ns) return 0; state.duty_cycle = duty_ns; state.period = period_ns; return pwm_apply_state(pwm, &state); } /** * pwm_set_polarity() - configure the polarity of a PWM signal * @pwm: PWM device * @polarity: new polarity of the PWM signal * * Note that the polarity cannot be configured while the PWM device is * enabled. * * Returns: 0 on success or a negative error code on failure. */ static inline int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) { struct pwm_state state; if (!pwm) return -EINVAL; pwm_get_state(pwm, &state); if (state.polarity == polarity) return 0; /* * Changing the polarity of a running PWM without adjusting the * dutycycle/period value is a bit risky (can introduce glitches). * Return -EBUSY in this case. * Note that this is allowed when using pwm_apply_state() because * the user specifies all the parameters. */ if (state.enabled) return -EBUSY; state.polarity = polarity; return pwm_apply_state(pwm, &state); } /** * 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) { struct pwm_state state; if (!pwm) return -EINVAL; pwm_get_state(pwm, &state); if (state.enabled) return 0; state.enabled = true; return pwm_apply_state(pwm, &state); } /** * pwm_disable() - stop a PWM output toggling * @pwm: PWM device */ static inline void pwm_disable(struct pwm_device *pwm) { struct pwm_state state; if (!pwm) return; pwm_get_state(pwm, &state); if (!state.enabled) return; state.enabled = false; pwm_apply_state(pwm, &state); } /* PWM provider APIs */ int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, unsigned long timeout); int pwm_set_chip_data(struct pwm_device *pwm, void *data); void *pwm_get_chip_data(struct pwm_device *pwm); int pwmchip_add_with_polarity(struct pwm_chip *chip, enum pwm_polarity polarity); int pwmchip_add(struct pwm_chip *chip); int pwmchip_remove(struct pwm_chip *chip); struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, const char *label); struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args); struct pwm_device *pwm_get(struct device *dev, const char *con_id); struct pwm_device *of_pwm_get(struct device_node *np, 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_of_pwm_get(struct device *dev, struct device_node *np, const char *con_id); void devm_pwm_put(struct device *dev, struct pwm_device *pwm); #else static inline struct pwm_device *pwm_request(int pwm_id, const char *label) { return ERR_PTR(-ENODEV); } static inline void pwm_free(struct pwm_device *pwm) { } static inline int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) { return -ENOTSUPP; } static inline int pwm_adjust_config(struct pwm_device *pwm) { return -ENOTSUPP; } static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) { return -EINVAL; } static inline int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, unsigned long timeout) { return -EINVAL; } static inline int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity) { return -ENOTSUPP; } static inline int pwm_enable(struct pwm_device *pwm) { return -EINVAL; } static inline void pwm_disable(struct pwm_device *pwm) { } static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) { return -EINVAL; } static inline void *pwm_get_chip_data(struct pwm_device *pwm) { return NULL; } static inline int pwmchip_add(struct pwm_chip *chip) { return -EINVAL; } static inline int pwmchip_add_inversed(struct pwm_chip *chip) { return -EINVAL; } static inline int pwmchip_remove(struct pwm_chip *chip) { return -EINVAL; } static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, const char *label) { return ERR_PTR(-ENODEV); } static inline struct pwm_device *pwm_get(struct device *dev, const char *consumer) { return ERR_PTR(-ENODEV); } static inline struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) { return ERR_PTR(-ENODEV); } static inline void pwm_put(struct pwm_device *pwm) { } static inline struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer) { return ERR_PTR(-ENODEV); } static inline struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, const char *con_id) { return ERR_PTR(-ENODEV); } static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) { } #endif static inline void pwm_apply_args(struct pwm_device *pwm) { struct pwm_state state = { }; /* * PWM users calling pwm_apply_args() expect to have a fresh config * where the polarity and period are set according to pwm_args info. * The problem is, polarity can only be changed when the PWM is * disabled. * * PWM drivers supporting hardware readout may declare the PWM device * as enabled, and prevent polarity setting, which changes from the * existing behavior, where all PWM devices are declared as disabled * at startup (even if they are actually enabled), thus authorizing * polarity setting. * * To fulfill this requirement, we apply a new state which disables * the PWM device and set the reference period and polarity config. * * Note that PWM users requiring a smooth handover between the * bootloader and the kernel (like critical regulators controlled by * PWM devices) will have to switch to the atomic API and avoid calling * pwm_apply_args(). */ state.enabled = false; state.polarity = pwm->args.polarity; state.period = pwm->args.period; pwm_apply_state(pwm, &state); } struct pwm_lookup { struct list_head list; const char *provider; unsigned int index; const char *dev_id; const char *con_id; unsigned int period; enum pwm_polarity polarity; const char *module; /* optional, may be NULL */ }; #define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ _period, _polarity, _module) \ { \ .provider = _provider, \ .index = _index, \ .dev_id = _dev_id, \ .con_id = _con_id, \ .period = _period, \ .polarity = _polarity, \ .module = _module, \ } #define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ _polarity, NULL) #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 #ifdef CONFIG_PWM_SYSFS void pwmchip_sysfs_export(struct pwm_chip *chip); void pwmchip_sysfs_unexport(struct pwm_chip *chip); void pwmchip_sysfs_unexport_children(struct pwm_chip *chip); #else static inline void pwmchip_sysfs_export(struct pwm_chip *chip) { } static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) { } static inline void pwmchip_sysfs_unexport_children(struct pwm_chip *chip) { } #endif /* CONFIG_PWM_SYSFS */ #endif /* __LINUX_PWM_H */