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>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index e4963b0f45da..d98519996927 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -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;