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authorLukasz Luba <l.luba@partner.samsung.com>2018-12-05 12:05:53 +0100
committerMyungJoo Ham <myungjoo.ham@samsung.com>2018-12-11 11:09:47 +0900
commit83f8ca45afbf041e312909f442128b99657d90b7 (patch)
treed9f1ef6d6749aaaa6963cea58747a8024a24f61e /drivers/devfreq
parent633141721b5bfce7017033a767208af591134b8f (diff)
downloadlinux-83f8ca45afbf041e312909f442128b99657d90b7.tar.bz2
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>
Diffstat (limited to 'drivers/devfreq')
-rw-r--r--drivers/devfreq/devfreq.c47
1 files changed, 41 insertions, 6 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index a9fd61bbacf1..46517b61b3a2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -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);