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Commit 7fd4edc5 authored by Yoshihiro Shimoda's avatar Yoshihiro Shimoda Committed by Thierry Reding
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pwm: sysfs: Add suspend/resume support 



According to the Documentation/pwm.txt, all PWM consumers should have
power management. Since this sysfs interface is one of consumers so that
this patch adds suspend/resume support.

Signed-off-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarSimon Horman <horms+renesas@verge.net.au>
[thierry.reding@gmail.com: fix build warnings for !PM]
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 321a7cea

drivers/pwm/sysfs.c

+102 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ struct pwm_export { 
	struct device child;

	struct pwm_device *pwm;

	struct mutex lock;

	struct pwm_state suspend;

};



static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -381,10 +382,111 @@ static struct attribute *pwm_chip_attrs[] = { 
};

ATTRIBUTE_GROUPS(pwm_chip);



/* takes export->lock on success */

static struct pwm_export *pwm_class_get_state(struct device *parent,

					      struct pwm_device *pwm,

					      struct pwm_state *state)

{

	struct device *child;

	struct pwm_export *export;



	if (!test_bit(PWMF_EXPORTED, &pwm->flags))

		return NULL;



	child = device_find_child(parent, pwm, pwm_unexport_match);

	if (!child)

		return NULL;



	export = child_to_pwm_export(child);

	put_device(child);	/* for device_find_child() */



	mutex_lock(&export->lock);

	pwm_get_state(pwm, state);



	return export;

}



static int pwm_class_apply_state(struct pwm_export *export,

				 struct pwm_device *pwm,

				 struct pwm_state *state)

{

	int ret = pwm_apply_state(pwm, state);



	/* release lock taken in pwm_class_get_state */

	mutex_unlock(&export->lock);



	return ret;

}



static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)

{

	struct pwm_chip *chip = dev_get_drvdata(parent);

	unsigned int i;

	int ret = 0;



	for (i = 0; i < npwm; i++) {

		struct pwm_device *pwm = &chip->pwms[i];

		struct pwm_state state;

		struct pwm_export *export;



		export = pwm_class_get_state(parent, pwm, &state);

		if (!export)

			continue;



		state.enabled = export->suspend.enabled;

		ret = pwm_class_apply_state(export, pwm, &state);

		if (ret < 0)

			break;

	}



	return ret;

}



static int __maybe_unused pwm_class_suspend(struct device *parent)

{

	struct pwm_chip *chip = dev_get_drvdata(parent);

	unsigned int i;

	int ret = 0;



	for (i = 0; i < chip->npwm; i++) {

		struct pwm_device *pwm = &chip->pwms[i];

		struct pwm_state state;

		struct pwm_export *export;



		export = pwm_class_get_state(parent, pwm, &state);

		if (!export)

			continue;



		export->suspend = state;

		state.enabled = false;

		ret = pwm_class_apply_state(export, pwm, &state);

		if (ret < 0) {

			/*

			 * roll back the PWM devices that were disabled by

			 * this suspend function.

			 */

			pwm_class_resume_npwm(parent, i);

			break;

		}

	}



	return ret;

}



static int __maybe_unused pwm_class_resume(struct device *parent)

{

	struct pwm_chip *chip = dev_get_drvdata(parent);



	return pwm_class_resume_npwm(parent, chip->npwm);

}



static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);



static struct class pwm_class = {

	.name = "pwm",

	.owner = THIS_MODULE,

	.dev_groups = pwm_chip_groups,

	.pm = &pwm_class_pm_ops,

};



static int pwmchip_sysfs_match(struct device *parent, const void *data)