| /* 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 { |
| u64 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 { |
| u64 period; |
| u64 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: last applied state |
| * @last: last implemented state (for PWM_DEBUG) |
| */ |
| 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; |
| struct pwm_state last; |
| }; |
| |
| /** |
| * 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, u64 period) |
| { |
| if (pwm) |
| pwm->state.period = period; |
| } |
| |
| static inline u64 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 u64 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 |
| * @capture: capture and report PWM signal |
| * @apply: atomically apply a new PWM config |
| * @get_state: get the current PWM state. This function is only |
| * called once per PWM device when the PWM chip is |
| * registered. |
| * @owner: helps prevent removal of modules exporting active PWMs |
| * @config: configure duty cycles and period length for this PWM |
| * @set_polarity: configure the polarity of this PWM |
| * @enable: enable PWM output toggling |
| * @disable: disable PWM output toggling |
| */ |
| struct pwm_ops { |
| int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); |
| void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); |
| int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, |
| struct pwm_capture *result, unsigned long timeout); |
| int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, |
| const struct pwm_state *state); |
| void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, |
| struct pwm_state *state); |
| struct module *owner; |
| |
| /* Only used by legacy drivers */ |
| 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 (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); |
| void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); |
| }; |
| |
| /** |
| * struct pwm_chip - abstract a PWM controller |
| * @dev: device providing the PWMs |
| * @ops: callbacks for this PWM controller |
| * @base: number of first PWM controlled by this chip |
| * @npwm: number of PWMs controlled by this chip |
| * @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 |
| * @list: list node for internal use |
| * @pwms: array of PWM devices allocated by the framework |
| */ |
| struct pwm_chip { |
| struct device *dev; |
| const struct pwm_ops *ops; |
| int base; |
| unsigned int npwm; |
| |
| struct pwm_device * (*of_xlate)(struct pwm_chip *pc, |
| const struct of_phandle_args *args); |
| unsigned int of_pwm_n_cells; |
| |
| /* only used internally by the PWM framework */ |
| struct list_head list; |
| struct pwm_device *pwms; |
| }; |
| |
| /** |
| * 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, 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) |
| { |
| 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_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 *dev, 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); |
| struct pwm_device *devm_fwnode_pwm_get(struct device *dev, |
| struct fwnode_handle *fwnode, |
| 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_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_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 *dev, |
| 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 struct pwm_device * |
| devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, |
| 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); |
| #else |
| static inline void pwmchip_sysfs_export(struct pwm_chip *chip) |
| { |
| } |
| |
| static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
| { |
| } |
| #endif /* CONFIG_PWM_SYSFS */ |
| |
| #endif /* __LINUX_PWM_H */ |