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Commit 83f8ca45 authored by Lukasz Luba's avatar Lukasz Luba Committed by MyungJoo Ham
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PM / devfreq: add support for suspend/resume of a devfreq device 



The patch prepares devfreq device for handling suspend/resume
functionality. The new fields will store needed information during this
process. Devfreq framework handles opp-suspend DT entry and there is no
need of modyfications in the drivers code. It uses atomic variables to
make sure no race condition affects the process.

Suggested-by: default avatarTobias Jakobi <tjakobi@math.uni-bielefeld.de>
Suggested-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarLukasz Luba <l.luba@partner.samsung.com>
Reviewed-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent 63314172

drivers/devfreq/devfreq.c

+41 −6
Original line number Diff line number Diff line
@@ -316,6 +316,10 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, 
			"Couldn't update frequency transition information.\n");



	devfreq->previous_freq = new_freq;



	if (devfreq->suspend_freq)

		devfreq->resume_freq = cur_freq;



	return err;

}
@@ -667,6 +671,9 @@ struct devfreq *devfreq_add_device(struct device *dev, 
	}

	devfreq->max_freq = devfreq->scaling_max_freq;



	devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);

	atomic_set(&devfreq->suspend_count, 0);



	dev_set_name(&devfreq->dev, "devfreq%d",

				atomic_inc_return(&devfreq_no));

	err = device_register(&devfreq->dev);
@@ -867,14 +874,28 @@ EXPORT_SYMBOL(devm_devfreq_remove_device); 
 */

int devfreq_suspend_device(struct devfreq *devfreq)

{

	int ret;



	if (!devfreq)

		return -EINVAL;



	if (!devfreq->governor)

	if (atomic_inc_return(&devfreq->suspend_count) > 1)

		return 0;



	return devfreq->governor->event_handler(devfreq,

	if (devfreq->governor) {

		ret = devfreq->governor->event_handler(devfreq,

					DEVFREQ_GOV_SUSPEND, NULL);

		if (ret)

			return ret;

	}



	if (devfreq->suspend_freq) {

		ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL(devfreq_suspend_device);
@@ -888,14 +909,28 @@ EXPORT_SYMBOL(devfreq_suspend_device); 
 */

int devfreq_resume_device(struct devfreq *devfreq)

{

	int ret;



	if (!devfreq)

		return -EINVAL;



	if (!devfreq->governor)

	if (atomic_dec_return(&devfreq->suspend_count) >= 1)

		return 0;



	return devfreq->governor->event_handler(devfreq,

	if (devfreq->resume_freq) {

		ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);

		if (ret)

			return ret;

	}



	if (devfreq->governor) {

		ret = devfreq->governor->event_handler(devfreq,

					DEVFREQ_GOV_RESUME, NULL);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL(devfreq_resume_device);

include/linux/devfreq.h

+7 −0
Original line number Diff line number Diff line
@@ -131,6 +131,9 @@ struct devfreq_dev_profile { 
 * @scaling_min_freq:	Limit minimum frequency requested by OPP interface

 * @scaling_max_freq:	Limit maximum frequency requested by OPP interface

 * @stop_polling:	 devfreq polling status of a device.

 * @suspend_freq:	 frequency of a device set during suspend phase.

 * @resume_freq:	 frequency of a device set in resume phase.

 * @suspend_count:	 suspend requests counter for a device.

 * @total_trans:	Number of devfreq transitions

 * @trans_table:	Statistics of devfreq transitions

 * @time_in_state:	Statistics of devfreq states
@@ -167,6 +170,10 @@ struct devfreq { 
	unsigned long scaling_max_freq;

	bool stop_polling;



	unsigned long suspend_freq;

	unsigned long resume_freq;

	atomic_t suspend_count;



	/* information for device frequency transition */

	unsigned int total_trans;

	unsigned int *trans_table;