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pwm: Introduce the pwm_args concept

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Currently the PWM core mixes the current PWM state with the per-platform
reference config (specified through the PWM lookup table, DT definition
or directly hardcoded in PWM drivers).

Create a struct pwm_args to store this reference configuration, so that
PWM users can differentiate between the current and reference
configurations.

Patch all places where pwm->args should be initialized. We keep the
pwm_set_polarity/period() calls until all PWM users are patched to use
pwm_args instead of pwm_get_period/polarity().

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[thierry.reding@gmail.com: reword kerneldoc comments]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Boris Brezillon
2016-04-14 21:17:21 +02:00
committed by Thierry Reding
parent f55532a0c0
commit e39c0df1be
4 changed files with 49 additions and 9 deletions
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33
include/linux/pwm.h
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@@ -74,6 +74,24 @@ enum pwm_polarity {
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_ENABLED = 1 << 1,
@@ -92,6 +110,7 @@ enum {
* @period: period of the PWM signal (in nanoseconds)
* @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
* @polarity: polarity of the PWM signal
* @args: PWM arguments
*/
struct pwm_device {
const char *label;
@@ -105,6 +124,8 @@ struct pwm_device {
unsigned int period;
unsigned int duty_cycle;
enum pwm_polarity polarity;
struct pwm_args args;
};
static inline bool pwm_is_enabled(const struct pwm_device *pwm)
@@ -144,6 +165,18 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
return pwm ? pwm->polarity : PWM_POLARITY_NORMAL;
}
static inline void pwm_get_args(const struct pwm_device *pwm,
struct pwm_args *args)
{
*args = pwm->args;
}
static inline void pwm_apply_args(struct pwm_device *pwm)
{
pwm_set_period(pwm, pwm->args.period);
pwm_set_polarity(pwm, pwm->args.polarity);
}
/**
* struct pwm_ops - PWM controller operations
* @request: optional hook for requesting a PWM