diff options
Diffstat (limited to 'include/linux/pwm.h')
| -rw-r--r-- | include/linux/pwm.h | 322 |
1 files changed, 187 insertions, 135 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 161e91167b9c..b11ae91723f8 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -2,10 +2,16 @@ #ifndef __LINUX_PWM_H #define __LINUX_PWM_H +#include <linux/cdev.h> +#include <linux/device.h> #include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> +MODULE_IMPORT_NS("PWM"); + struct pwm_chip; /** @@ -41,8 +47,33 @@ struct pwm_args { }; enum { - PWMF_REQUESTED = 1 << 0, - PWMF_EXPORTED = 1 << 1, + PWMF_REQUESTED = 0, + 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; }; /* @@ -69,9 +100,7 @@ struct pwm_state { * @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) @@ -80,9 +109,7 @@ 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; @@ -95,8 +122,8 @@ struct 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_state(). Drivers may have to slightly tweak that state before programming it to - * hardware. If pwm_apply_state() was never called, this returns either the current hardware + * 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, @@ -114,12 +141,6 @@ static inline bool pwm_is_enabled(const struct pwm_device *pwm) 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; @@ -129,12 +150,6 @@ static inline u64 pwm_get_period(const struct pwm_device *pwm) 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; @@ -160,20 +175,20 @@ static inline void pwm_get_args(const struct pwm_device *pwm, } /** - * pwm_init_state() - prepare a new state to be applied with pwm_apply_state() + * 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_state(). This is a convenient function + * 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_state(). + * 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_state() without adjusting ->duty_cycle + * 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, @@ -205,6 +220,8 @@ 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) @@ -229,10 +246,10 @@ pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) * * pwm_init_state(pwm, &state); * pwm_set_relative_duty_cycle(&state, 50, 100); - * pwm_apply_state(pwm, &state); + * 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, @@ -258,60 +275,129 @@ struct pwm_capture { unsigned int duty_cycle; }; +#define PWM_WFHWSIZE 20 + /** * 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 + * @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. - * @owner: helps prevent removal of modules exporting active PWMs + * @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, struct pwm_state *state); - struct module *owner; }; /** * struct pwm_chip - abstract a PWM controller * @dev: device providing the PWMs + * @cdev: &struct cdev for this device * @ops: callbacks for this PWM controller - * @base: number of first PWM controlled by this chip + * @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 - * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier - * @list: list node for internal use + * @atomic: can the driver's ->apply() be called in atomic context + * @gpio: &struct gpio_chip to operate this PWM chip's lines as GPO + * @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; + struct cdev cdev; const struct pwm_ops *ops; - int base; + struct module *owner; + unsigned int id; unsigned int npwm; - struct pwm_device * (*of_xlate)(struct pwm_chip *pc, + struct pwm_device * (*of_xlate)(struct pwm_chip *chip, const struct of_phandle_args *args); - unsigned int of_pwm_n_cells; + bool atomic; /* only used internally by the PWM framework */ - struct list_head list; - struct pwm_device *pwms; + struct gpio_chip gpio; + 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); }; -#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); +/** + * 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.parent; +} + +static inline void *pwmchip_get_drvdata(const struct pwm_chip *chip) +{ + return dev_get_drvdata(&chip->dev); +} + +static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data) +{ + dev_set_drvdata(&chip->dev, data); +} + +#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); /** @@ -339,7 +425,7 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns, state.duty_cycle = duty_ns; state.period = period_ns; - return pwm_apply_state(pwm, &state); + return pwm_apply_might_sleep(pwm, &state); } /** @@ -360,7 +446,7 @@ static inline int pwm_enable(struct pwm_device *pwm) return 0; state.enabled = true; - return pwm_apply_state(pwm, &state); + return pwm_apply_might_sleep(pwm, &state); } /** @@ -379,27 +465,41 @@ static inline void pwm_disable(struct pwm_device *pwm) return; state.enabled = false; - pwm_apply_state(pwm, &state); + pwm_apply_might_sleep(pwm, &state); +} + +/** + * 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) +{ + return !pwm->chip->atomic; } /* 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); +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); +int __pwmchip_add(struct pwm_chip *chip, struct module *owner); +#define pwmchip_add(chip) __pwmchip_add(chip, THIS_MODULE) void pwmchip_remove(struct pwm_chip *chip); -int devm_pwmchip_add(struct device *dev, struct pwm_chip *chip); +/* + * For FFI wrapper use only: + * The Rust PWM abstraction needs this to properly free the pwm_chip. + */ +void pwmchip_release(struct device *dev); -struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, - unsigned int index, - const char *label); +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 *of_pwm_xlate_with_flags(struct pwm_chip *pc, +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 *pc, +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); @@ -410,27 +510,32 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, const char *con_id); #else -static inline struct pwm_device *pwm_request(int pwm_id, const char *label) +static inline bool pwm_might_sleep(struct pwm_device *pwm) { - might_sleep(); - return ERR_PTR(-ENODEV); + return true; } -static inline void pwm_free(struct pwm_device *pwm) +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_state(struct pwm_device *pwm, - const struct pwm_state *state) +static inline int pwm_apply_atomic(struct pwm_device *pwm, + const struct pwm_state *state) { - might_sleep(); - return -ENOTSUPP; + 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 -ENOTSUPP; + return -EOPNOTSUPP; } static inline int pwm_config(struct pwm_device *pwm, int duty_ns, @@ -440,13 +545,6 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_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) { might_sleep(); @@ -458,14 +556,22 @@ static inline void pwm_disable(struct pwm_device *pwm) might_sleep(); } -static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) +static inline void pwmchip_put(struct pwm_chip *chip) { - return -EINVAL; } -static inline void *pwm_get_chip_data(struct pwm_device *pwm) +static inline struct pwm_chip *pwmchip_alloc(struct device *parent, + unsigned int npwm, + size_t sizeof_priv) { - return NULL; + 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) @@ -483,14 +589,6 @@ 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) { @@ -519,39 +617,6 @@ devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, } #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; - state.usage_power = false; - - pwm_apply_state(pwm, &state); -} - struct pwm_lookup { struct list_head list; const char *provider; @@ -579,7 +644,7 @@ 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 @@ -592,17 +657,4 @@ 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 */ |