Commit e39c0df1 authored by Boris Brezillon's avatar Boris Brezillon Committed by Thierry Reding
Browse files

pwm: Introduce the pwm_args concept 



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: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
[thierry.reding@gmail.com: reword kerneldoc comments]
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent f55532a0

drivers/pwm/core.c

+14 −7
Original line number Diff line number Diff line
@@ -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;

drivers/pwm/pwm-clps711x.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

}

drivers/pwm/pwm-pxa.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

}

include/linux/pwm.h

+33 −0
Original line number Diff line number Diff line
@@ -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

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