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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/pwm/core.c
View File

@ -128,6 +128,13 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
set_bit(PWMF_REQUESTED, &pwm->flags);
pwm->label = label;
/*
* FIXME: This should be removed once all PWM users properly make use
* of struct pwm_args to initialize the PWM device. As long as this is
* here, the PWM state and hardware state can get out of sync.
*/
pwm_apply_args(pwm);
return 0;
}
@ -146,12 +153,12 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
pwm_set_period(pwm, args->args[1]);
pwm->args.period = args->args[1];
if (args->args[2] & PWM_POLARITY_INVERTED)
pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
pwm->args.polarity = PWM_POLARITY_INVERSED;
else
pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
pwm->args.polarity = PWM_POLARITY_NORMAL;
return pwm;
}
@ -172,7 +179,7 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
pwm_set_period(pwm, args->args[1]);
pwm->args.period = args->args[1];
return pwm;
}
@ -747,13 +754,13 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
if (!chip)
goto out;
pwm->args.period = chosen->period;
pwm->args.polarity = chosen->polarity;
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
goto out;
pwm_set_period(pwm, chosen->period);
pwm_set_polarity(pwm, chosen->polarity);
out:
mutex_unlock(&pwm_lookup_lock);
return pwm;

2
drivers/pwm/pwm-clps711x.c
View File

@ -60,7 +60,7 @@ static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
return -EINVAL;
/* Store constant period value */
pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq));
pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
return 0;
}

2
drivers/pwm/pwm-pxa.c
View File

@ -160,7 +160,7 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
if (IS_ERR(pwm))
return pwm;
pwm_set_period(pwm, args->args[0]);
pwm->args.period = args->args[0];
return pwm;
}

33
include/linux/pwm.h
View File

@ -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