diff options
Diffstat (limited to 'include/linux/pwm.h')
| -rw-r--r-- | include/linux/pwm.h | 167 |
1 files changed, 101 insertions, 66 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 4a6568dfdf3f..63a17d2b4ec8 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -2,10 +2,14 @@ #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("PWM"); + struct pwm_chip; /** @@ -45,6 +49,31 @@ enum { PWMF_EXPORTED = 1, }; +/** + * struct pwm_waveform - description of a PWM waveform + * @period_length_ns: PWM period + * @duty_length_ns: PWM duty cycle + * @duty_offset_ns: offset of the rising edge from the period's start + * + * This is a representation of a PWM waveform alternative to struct pwm_state + * below. It's more expressive than struct pwm_state as it contains a + * duty_offset_ns and so can represent offsets other than zero (with .polarity = + * PWM_POLARITY_NORMAL) and period - duty_cycle (.polarity = + * PWM_POLARITY_INVERSED). + * + * Note there is no explicit bool for enabled. A "disabled" PWM is represented + * by .period_length_ns = 0. Note further that the behaviour of a "disabled" PWM + * is undefined. Depending on the hardware's capabilities it might drive the + * active or inactive level, go high-z or even continue to toggle. + * + * The unit for all three members is nanoseconds. + */ +struct pwm_waveform { + u64 period_length_ns; + u64 duty_length_ns; + u64 duty_offset_ns; +}; + /* * struct pwm_state - state of a PWM channel * @period: PWM period (in nanoseconds) @@ -189,6 +218,8 @@ static inline void pwm_init_state(const struct pwm_device *pwm, * * pwm_get_state(pwm, &state); * duty = pwm_get_relative_duty_cycle(&state, 100); + * + * Returns: rounded relative duty cycle multiplied by @scale */ static inline unsigned int pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) @@ -215,8 +246,8 @@ pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) * 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). + * Returns: 0 on success or ``-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, @@ -247,16 +278,30 @@ struct pwm_capture { * @request: optional hook for requesting a PWM * @free: optional hook for freeing a PWM * @capture: capture and report PWM signal + * @sizeof_wfhw: size (in bytes) of driver specific waveform presentation + * @round_waveform_tohw: convert a struct pwm_waveform to driver specific presentation + * @round_waveform_fromhw: convert a driver specific waveform presentation to struct pwm_waveform + * @read_waveform: read driver specific waveform presentation from hardware + * @write_waveform: write driver specific waveform presentation to hardware * @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. + * @get_state: get the current PWM state. */ 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); + + size_t sizeof_wfhw; + int (*round_waveform_tohw)(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_waveform *wf, void *wfhw); + int (*round_waveform_fromhw)(struct pwm_chip *chip, struct pwm_device *pwm, + const void *wfhw, struct pwm_waveform *wf); + int (*read_waveform)(struct pwm_chip *chip, struct pwm_device *pwm, + void *wfhw); + int (*write_waveform)(struct pwm_chip *chip, struct pwm_device *pwm, + const void *wfhw); + int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state); int (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, @@ -272,11 +317,14 @@ struct pwm_ops { * @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 - * @driver_data: Private pointer for driver specific info + * @uses_pwmchip_alloc: signals if pwmchip_allow was used to allocate this chip + * @operational: signals if the chip can be used (or is already deregistered) + * @nonatomic_lock: mutex for nonatomic chips + * @atomic_lock: mutex for atomic chips * @pwms: array of PWM devices allocated by the framework */ struct pwm_chip { - struct device *dev; + struct device dev; const struct pwm_ops *ops; struct module *owner; unsigned int id; @@ -287,37 +335,61 @@ struct pwm_chip { bool atomic; /* only used internally by the PWM framework */ - void *driver_data; - struct pwm_device *pwms; + bool uses_pwmchip_alloc; + bool operational; + union { + /* + * depending on the chip being atomic or not either the mutex or + * the spinlock is used. It protects .operational and + * synchronizes the callbacks in .ops + */ + struct mutex nonatomic_lock; + spinlock_t atomic_lock; + }; + struct pwm_device pwms[] __counted_by(npwm); }; +/** + * pwmchip_supports_waveform() - checks if the given chip supports waveform callbacks + * @chip: The pwm_chip to test + * + * Returns: true iff the pwm chip support the waveform functions like + * pwm_set_waveform_might_sleep() and pwm_round_waveform_might_sleep() + */ +static inline bool pwmchip_supports_waveform(struct pwm_chip *chip) +{ + /* + * only check for .write_waveform(). If that is available, + * .round_waveform_tohw() and .round_waveform_fromhw() asserted to be + * available, too, in pwmchip_add(). + */ + return chip->ops->write_waveform != NULL; +} + static inline struct device *pwmchip_parent(const struct pwm_chip *chip) { - return chip->dev; + return chip->dev.parent; } -static inline void *pwmchip_get_drvdata(struct pwm_chip *chip) +static inline void *pwmchip_get_drvdata(const struct pwm_chip *chip) { - /* - * After pwm_chip got a dedicated struct device, this can be replaced by - * dev_get_drvdata(&chip->dev); - */ - return chip->driver_data; + return dev_get_drvdata(&chip->dev); } static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data) { - /* - * After pwm_chip got a dedicated struct device, this can be replaced by - * dev_set_drvdata(&chip->dev, data); - */ - chip->driver_data = data; + dev_set_drvdata(&chip->dev, data); } -#if IS_ENABLED(CONFIG_PWM) -/* PWM user APIs */ +#if IS_REACHABLE(CONFIG_PWM) + +/* PWM consumer APIs */ +int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf); +int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf); +int pwm_set_waveform_might_sleep(struct pwm_device *pwm, const struct pwm_waveform *wf, bool exact); 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_get_state_hw(struct pwm_device *pwm, struct pwm_state *state); int pwm_adjust_config(struct pwm_device *pwm); /** @@ -400,9 +472,6 @@ static inline bool pwm_might_sleep(struct pwm_device *pwm) } /* PWM provider APIs */ -int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, - unsigned long timeout); - 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); @@ -414,10 +483,6 @@ 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) __devm_pwmchip_add(dev, chip, THIS_MODULE) -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 *chip, const struct of_phandle_args *args); struct pwm_device *of_pwm_single_xlate(struct pwm_chip *chip, @@ -449,6 +514,11 @@ static inline int pwm_apply_atomic(struct pwm_device *pwm, return -EOPNOTSUPP; } +static inline int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state) +{ + return -EOPNOTSUPP; +} + static inline int pwm_adjust_config(struct pwm_device *pwm) { return -EOPNOTSUPP; @@ -472,13 +542,6 @@ static inline void pwm_disable(struct pwm_device *pwm) might_sleep(); } -static inline int pwm_capture(struct pwm_device *pwm, - struct pwm_capture *result, - unsigned long timeout) -{ - return -EINVAL; -} - static inline void pwmchip_put(struct pwm_chip *chip) { } @@ -512,14 +575,6 @@ static inline int devm_pwmchip_add(struct device *dev, 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) -{ - might_sleep(); - return ERR_PTR(-ENODEV); -} - static inline struct pwm_device *pwm_get(struct device *dev, const char *consumer) { @@ -581,13 +636,6 @@ static inline void pwm_apply_args(struct pwm_device *pwm) pwm_apply_might_sleep(pwm, &state); } -/* only for backwards-compatibility, new code should not use this */ -static inline int pwm_apply_state(struct pwm_device *pwm, - const struct pwm_state *state) -{ - return pwm_apply_might_sleep(pwm, state); -} - struct pwm_lookup { struct list_head list; const char *provider; @@ -615,7 +663,7 @@ struct pwm_lookup { PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ _polarity, NULL) -#if IS_ENABLED(CONFIG_PWM) +#if IS_REACHABLE(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 @@ -628,17 +676,4 @@ 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 */ |