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615 lines
16 KiB
615 lines
16 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef __LINUX_PWM_H |
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#define __LINUX_PWM_H |
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|
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#include <linux/err.h> |
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#include <linux/mutex.h> |
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#include <linux/of.h> |
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struct pwm_capture; |
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struct seq_file; |
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struct pwm_chip; |
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|
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/** |
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* enum pwm_polarity - polarity of a PWM signal |
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* @PWM_POLARITY_NORMAL: a high signal for the duration of the duty- |
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* cycle, followed by a low signal for the remainder of the pulse |
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* period |
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* @PWM_POLARITY_INVERSED: a low signal for the duration of the duty- |
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* cycle, followed by a high signal for the remainder of the pulse |
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* period |
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*/ |
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enum pwm_polarity { |
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PWM_POLARITY_NORMAL, |
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PWM_POLARITY_INVERSED, |
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}; |
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|
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/** |
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* struct pwm_args - board-dependent PWM arguments |
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* @period: reference period |
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* @polarity: reference polarity |
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* |
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* This structure describes board-dependent arguments attached to a PWM |
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* device. These arguments are usually retrieved from the PWM lookup table or |
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* device tree. |
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* |
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* Do not confuse this with the PWM state: PWM arguments represent the initial |
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* configuration that users want to use on this PWM device rather than the |
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* current PWM hardware state. |
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*/ |
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struct pwm_args { |
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u64 period; |
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enum pwm_polarity polarity; |
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}; |
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enum { |
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PWMF_REQUESTED = 1 << 0, |
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PWMF_EXPORTED = 1 << 1, |
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}; |
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|
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/* |
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* struct pwm_state - state of a PWM channel |
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* @period: PWM period (in nanoseconds) |
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* @duty_cycle: PWM duty cycle (in nanoseconds) |
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* @polarity: PWM polarity |
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* @enabled: PWM enabled status |
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*/ |
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struct pwm_state { |
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u64 period; |
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u64 duty_cycle; |
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enum pwm_polarity polarity; |
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bool enabled; |
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}; |
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/** |
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* struct pwm_device - PWM channel object |
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* @label: name of the PWM device |
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* @flags: flags associated with the PWM device |
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* @hwpwm: per-chip relative index of the PWM device |
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* @pwm: global index of the PWM device |
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* @chip: PWM chip providing this PWM device |
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* @chip_data: chip-private data associated with the PWM device |
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* @args: PWM arguments |
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* @state: last applied state |
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* @last: last implemented state (for PWM_DEBUG) |
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*/ |
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struct pwm_device { |
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const char *label; |
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unsigned long flags; |
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unsigned int hwpwm; |
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unsigned int pwm; |
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struct pwm_chip *chip; |
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void *chip_data; |
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struct pwm_args args; |
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struct pwm_state state; |
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struct pwm_state last; |
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}; |
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/** |
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* pwm_get_state() - retrieve the current PWM state |
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* @pwm: PWM device |
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* @state: state to fill with the current PWM state |
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*/ |
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static inline void pwm_get_state(const struct pwm_device *pwm, |
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struct pwm_state *state) |
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{ |
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*state = pwm->state; |
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} |
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static inline bool pwm_is_enabled(const struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return state.enabled; |
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} |
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static inline void pwm_set_period(struct pwm_device *pwm, u64 period) |
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{ |
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if (pwm) |
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pwm->state.period = period; |
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} |
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static inline u64 pwm_get_period(const struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return state.period; |
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} |
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static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty) |
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{ |
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if (pwm) |
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pwm->state.duty_cycle = duty; |
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} |
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static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return state.duty_cycle; |
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} |
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static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return state.polarity; |
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} |
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static inline void pwm_get_args(const struct pwm_device *pwm, |
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struct pwm_args *args) |
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{ |
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*args = pwm->args; |
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} |
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/** |
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* pwm_init_state() - prepare a new state to be applied with pwm_apply_state() |
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* @pwm: PWM device |
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* @state: state to fill with the prepared PWM state |
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* |
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* This functions prepares a state that can later be tweaked and applied |
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* to the PWM device with pwm_apply_state(). This is a convenient function |
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* that first retrieves the current PWM state and the replaces the period |
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* and polarity fields with the reference values defined in pwm->args. |
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* Once the function returns, you can adjust the ->enabled and ->duty_cycle |
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* fields according to your needs before calling pwm_apply_state(). |
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* |
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* ->duty_cycle is initially set to zero to avoid cases where the current |
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* ->duty_cycle value exceed the pwm_args->period one, which would trigger |
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* an error if the user calls pwm_apply_state() without adjusting ->duty_cycle |
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* first. |
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*/ |
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static inline void pwm_init_state(const struct pwm_device *pwm, |
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struct pwm_state *state) |
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{ |
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struct pwm_args args; |
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/* First get the current state. */ |
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pwm_get_state(pwm, state); |
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/* Then fill it with the reference config */ |
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pwm_get_args(pwm, &args); |
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state->period = args.period; |
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state->polarity = args.polarity; |
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state->duty_cycle = 0; |
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} |
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/** |
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* pwm_get_relative_duty_cycle() - Get a relative duty cycle value |
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* @state: PWM state to extract the duty cycle from |
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* @scale: target scale of the relative duty cycle |
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* |
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* This functions converts the absolute duty cycle stored in @state (expressed |
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* in nanosecond) into a value relative to the period. |
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* |
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* For example if you want to get the duty_cycle expressed in percent, call: |
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* |
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* pwm_get_state(pwm, &state); |
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* duty = pwm_get_relative_duty_cycle(&state, 100); |
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*/ |
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static inline unsigned int |
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pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale) |
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{ |
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if (!state->period) |
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return 0; |
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return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale, |
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state->period); |
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} |
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/** |
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* pwm_set_relative_duty_cycle() - Set a relative duty cycle value |
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* @state: PWM state to fill |
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* @duty_cycle: relative duty cycle value |
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* @scale: scale in which @duty_cycle is expressed |
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* |
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* This functions converts a relative into an absolute duty cycle (expressed |
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* in nanoseconds), and puts the result in state->duty_cycle. |
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* |
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* For example if you want to configure a 50% duty cycle, call: |
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* |
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* pwm_init_state(pwm, &state); |
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* pwm_set_relative_duty_cycle(&state, 50, 100); |
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* pwm_apply_state(pwm, &state); |
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* |
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* This functions returns -EINVAL if @duty_cycle and/or @scale are |
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* inconsistent (@scale == 0 or @duty_cycle > @scale). |
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*/ |
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static inline int |
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pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, |
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unsigned int scale) |
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{ |
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if (!scale || duty_cycle > scale) |
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return -EINVAL; |
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state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle * |
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state->period, |
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scale); |
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return 0; |
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} |
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/** |
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* struct pwm_ops - PWM controller operations |
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* @request: optional hook for requesting a PWM |
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* @free: optional hook for freeing a PWM |
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* @capture: capture and report PWM signal |
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* @apply: atomically apply a new PWM config |
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* @get_state: get the current PWM state. This function is only |
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* called once per PWM device when the PWM chip is |
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* registered. |
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* @owner: helps prevent removal of modules exporting active PWMs |
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* @config: configure duty cycles and period length for this PWM |
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* @set_polarity: configure the polarity of this PWM |
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* @enable: enable PWM output toggling |
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* @disable: disable PWM output toggling |
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*/ |
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struct pwm_ops { |
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int (*request)(struct pwm_chip *chip, struct pwm_device *pwm); |
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void (*free)(struct pwm_chip *chip, struct pwm_device *pwm); |
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int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm, |
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struct pwm_capture *result, unsigned long timeout); |
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int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm, |
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const struct pwm_state *state); |
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void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, |
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struct pwm_state *state); |
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struct module *owner; |
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/* Only used by legacy drivers */ |
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int (*config)(struct pwm_chip *chip, struct pwm_device *pwm, |
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int duty_ns, int period_ns); |
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int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm, |
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enum pwm_polarity polarity); |
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int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm); |
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void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm); |
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}; |
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/** |
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* struct pwm_chip - abstract a PWM controller |
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* @dev: device providing the PWMs |
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* @ops: callbacks for this PWM controller |
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* @base: number of first PWM controlled by this chip |
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* @npwm: number of PWMs controlled by this chip |
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* @of_xlate: request a PWM device given a device tree PWM specifier |
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* @of_pwm_n_cells: number of cells expected in the device tree PWM specifier |
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* @list: list node for internal use |
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* @pwms: array of PWM devices allocated by the framework |
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*/ |
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struct pwm_chip { |
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struct device *dev; |
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const struct pwm_ops *ops; |
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int base; |
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unsigned int npwm; |
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struct pwm_device * (*of_xlate)(struct pwm_chip *pc, |
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const struct of_phandle_args *args); |
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unsigned int of_pwm_n_cells; |
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/* only used internally by the PWM framework */ |
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struct list_head list; |
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struct pwm_device *pwms; |
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}; |
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/** |
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* struct pwm_capture - PWM capture data |
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* @period: period of the PWM signal (in nanoseconds) |
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* @duty_cycle: duty cycle of the PWM signal (in nanoseconds) |
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*/ |
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struct pwm_capture { |
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unsigned int period; |
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unsigned int duty_cycle; |
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}; |
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#if IS_ENABLED(CONFIG_PWM) |
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/* PWM user APIs */ |
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struct pwm_device *pwm_request(int pwm_id, const char *label); |
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void pwm_free(struct pwm_device *pwm); |
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int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state); |
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int pwm_adjust_config(struct pwm_device *pwm); |
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/** |
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* pwm_config() - change a PWM device configuration |
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* @pwm: PWM device |
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* @duty_ns: "on" time (in nanoseconds) |
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* @period_ns: duration (in nanoseconds) of one cycle |
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* |
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* Returns: 0 on success or a negative error code on failure. |
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*/ |
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static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
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int period_ns) |
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{ |
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struct pwm_state state; |
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if (!pwm) |
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return -EINVAL; |
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if (duty_ns < 0 || period_ns < 0) |
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return -EINVAL; |
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pwm_get_state(pwm, &state); |
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if (state.duty_cycle == duty_ns && state.period == period_ns) |
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return 0; |
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state.duty_cycle = duty_ns; |
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state.period = period_ns; |
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return pwm_apply_state(pwm, &state); |
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} |
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/** |
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* pwm_enable() - start a PWM output toggling |
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* @pwm: PWM device |
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* |
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* Returns: 0 on success or a negative error code on failure. |
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*/ |
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static inline int pwm_enable(struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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if (!pwm) |
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return -EINVAL; |
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pwm_get_state(pwm, &state); |
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if (state.enabled) |
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return 0; |
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state.enabled = true; |
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return pwm_apply_state(pwm, &state); |
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} |
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/** |
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* pwm_disable() - stop a PWM output toggling |
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* @pwm: PWM device |
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*/ |
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static inline void pwm_disable(struct pwm_device *pwm) |
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{ |
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struct pwm_state state; |
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if (!pwm) |
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return; |
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pwm_get_state(pwm, &state); |
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if (!state.enabled) |
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return; |
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state.enabled = false; |
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pwm_apply_state(pwm, &state); |
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} |
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/* PWM provider APIs */ |
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int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, |
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unsigned long timeout); |
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int pwm_set_chip_data(struct pwm_device *pwm, void *data); |
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void *pwm_get_chip_data(struct pwm_device *pwm); |
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int pwmchip_add_with_polarity(struct pwm_chip *chip, |
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enum pwm_polarity polarity); |
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int pwmchip_add(struct pwm_chip *chip); |
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int pwmchip_remove(struct pwm_chip *chip); |
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struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
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unsigned int index, |
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const char *label); |
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struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, |
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const struct of_phandle_args *args); |
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struct pwm_device *pwm_get(struct device *dev, const char *con_id); |
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struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np, |
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const char *con_id); |
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void pwm_put(struct pwm_device *pwm); |
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struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); |
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struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, |
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const char *con_id); |
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struct pwm_device *devm_fwnode_pwm_get(struct device *dev, |
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struct fwnode_handle *fwnode, |
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const char *con_id); |
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void devm_pwm_put(struct device *dev, struct pwm_device *pwm); |
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#else |
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static inline struct pwm_device *pwm_request(int pwm_id, const char *label) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline void pwm_free(struct pwm_device *pwm) |
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{ |
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} |
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static inline int pwm_apply_state(struct pwm_device *pwm, |
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const struct pwm_state *state) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline int pwm_adjust_config(struct pwm_device *pwm) |
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{ |
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return -ENOTSUPP; |
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} |
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static inline int pwm_config(struct pwm_device *pwm, int duty_ns, |
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int period_ns) |
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{ |
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return -EINVAL; |
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} |
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static inline int pwm_capture(struct pwm_device *pwm, |
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struct pwm_capture *result, |
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unsigned long timeout) |
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{ |
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return -EINVAL; |
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} |
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static inline int pwm_enable(struct pwm_device *pwm) |
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{ |
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return -EINVAL; |
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} |
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static inline void pwm_disable(struct pwm_device *pwm) |
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{ |
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} |
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static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) |
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{ |
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return -EINVAL; |
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} |
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static inline void *pwm_get_chip_data(struct pwm_device *pwm) |
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{ |
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return NULL; |
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} |
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static inline int pwmchip_add(struct pwm_chip *chip) |
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{ |
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return -EINVAL; |
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} |
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static inline int pwmchip_remove(struct pwm_chip *chip) |
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{ |
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return -EINVAL; |
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} |
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static inline struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, |
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unsigned int index, |
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const char *label) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline struct pwm_device *pwm_get(struct device *dev, |
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const char *consumer) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline struct pwm_device *of_pwm_get(struct device *dev, |
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struct device_node *np, |
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const char *con_id) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline void pwm_put(struct pwm_device *pwm) |
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{ |
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} |
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static inline struct pwm_device *devm_pwm_get(struct device *dev, |
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const char *consumer) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline struct pwm_device *devm_of_pwm_get(struct device *dev, |
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struct device_node *np, |
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const char *con_id) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline struct pwm_device * |
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devm_fwnode_pwm_get(struct device *dev, struct fwnode_handle *fwnode, |
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const char *con_id) |
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{ |
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return ERR_PTR(-ENODEV); |
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} |
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static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) |
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{ |
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} |
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#endif |
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static inline void pwm_apply_args(struct pwm_device *pwm) |
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{ |
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struct pwm_state state = { }; |
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/* |
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* PWM users calling pwm_apply_args() expect to have a fresh config |
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* where the polarity and period are set according to pwm_args info. |
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* The problem is, polarity can only be changed when the PWM is |
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* disabled. |
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* |
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* PWM drivers supporting hardware readout may declare the PWM device |
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* as enabled, and prevent polarity setting, which changes from the |
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* existing behavior, where all PWM devices are declared as disabled |
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* at startup (even if they are actually enabled), thus authorizing |
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* polarity setting. |
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* |
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* To fulfill this requirement, we apply a new state which disables |
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* the PWM device and set the reference period and polarity config. |
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* |
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* Note that PWM users requiring a smooth handover between the |
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* bootloader and the kernel (like critical regulators controlled by |
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* PWM devices) will have to switch to the atomic API and avoid calling |
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* pwm_apply_args(). |
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*/ |
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|
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state.enabled = false; |
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state.polarity = pwm->args.polarity; |
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state.period = pwm->args.period; |
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pwm_apply_state(pwm, &state); |
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} |
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struct pwm_lookup { |
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struct list_head list; |
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const char *provider; |
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unsigned int index; |
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const char *dev_id; |
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const char *con_id; |
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unsigned int period; |
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enum pwm_polarity polarity; |
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const char *module; /* optional, may be NULL */ |
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}; |
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#define PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, \ |
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_period, _polarity, _module) \ |
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{ \ |
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.provider = _provider, \ |
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.index = _index, \ |
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.dev_id = _dev_id, \ |
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.con_id = _con_id, \ |
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.period = _period, \ |
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.polarity = _polarity, \ |
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.module = _module, \ |
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} |
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|
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#define PWM_LOOKUP(_provider, _index, _dev_id, _con_id, _period, _polarity) \ |
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PWM_LOOKUP_WITH_MODULE(_provider, _index, _dev_id, _con_id, _period, \ |
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_polarity, NULL) |
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|
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#if IS_ENABLED(CONFIG_PWM) |
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void pwm_add_table(struct pwm_lookup *table, size_t num); |
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void pwm_remove_table(struct pwm_lookup *table, size_t num); |
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#else |
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static inline void pwm_add_table(struct pwm_lookup *table, size_t num) |
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{ |
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} |
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static inline void pwm_remove_table(struct pwm_lookup *table, size_t num) |
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{ |
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} |
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#endif |
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#ifdef CONFIG_PWM_SYSFS |
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void pwmchip_sysfs_export(struct pwm_chip *chip); |
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void pwmchip_sysfs_unexport(struct pwm_chip *chip); |
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#else |
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static inline void pwmchip_sysfs_export(struct pwm_chip *chip) |
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{ |
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} |
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static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
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{ |
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} |
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#endif /* CONFIG_PWM_SYSFS */ |
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#endif /* __LINUX_PWM_H */
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