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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: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Suggested-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
Lukasz Luba 2018-12-05 12:05:53 +01:00 committed by MyungJoo Ham
parent 633141721b
commit 83f8ca45af
2 changed files with 48 additions and 6 deletions
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47
drivers/devfreq/devfreq.c
View File

@ -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,
DEVFREQ_GOV_SUSPEND, NULL);
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,
DEVFREQ_GOV_RESUME, NULL);
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);

7
include/linux/devfreq.h
View File

@ -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;