linux-kernel - Re: [PATCH v4 2/3] devfreq: Add suspend and resume apis

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Date:	Mon, 8 Oct 2012 14:12:39 +0530
From:	Rajagopal Venkat <rajagopal.venkat@...aro.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	myungjoo.ham@...sung.com, mturquette@...aro.org,
	kyungmin.park@...sung.com, patches@...aro.org,
	linaro-dev@...ts.linaro.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/3] devfreq: Add suspend and resume apis

On 8 October 2012 03:31, Rafael J. Wysocki <rjw@...k.pl> wrote:
> On Thursday 04 of October 2012 14:58:33 Rajagopal Venkat wrote:
>> Add devfreq suspend/resume apis for devfreq users. This patch
>> supports suspend and resume of devfreq load monitoring, required
>> for devices which can idle.
>>
>> Signed-off-by: Rajagopal Venkat <rajagopal.venkat@...aro.org>
>> Acked-by: MyungJoo Ham <myungjoo.ham@...sung.com>
>
> Well, I wonder if this may be tied in to the runtime PM framework, so that,
> for example, pm_runtime_suspend() will automatically suspend devfreq on
> success (and the runtime resume of the device will resume devfreq)?

That's a good idea. If you agree, we can handle this as separate patch on
top this patchset.

>
> Rafael
>
>
>> ---
>>  drivers/devfreq/devfreq.c                 | 28 ++++++++++++++++++++++++++++
>>  drivers/devfreq/governor.h                |  2 ++
>>  drivers/devfreq/governor_simpleondemand.c |  9 +++++++++
>>  include/linux/devfreq.h                   | 12 ++++++++++++
>>  4 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 41a4099..63e075e 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -428,6 +428,34 @@ int devfreq_remove_device(struct devfreq *devfreq)
>>  }
>>  EXPORT_SYMBOL(devfreq_remove_device);
>>
>> +/**
>> + * devfreq_suspend_device() - Suspend devfreq of a device.
>> + * @devfreq  the devfreq instance to be suspended
>> + */
>> +int devfreq_suspend_device(struct devfreq *devfreq)
>> +{
>> +     if (!devfreq)
>> +             return -EINVAL;
>> +
>> +     return devfreq->governor->event_handler(devfreq,
>> +                             DEVFREQ_GOV_SUSPEND, NULL);
>> +}
>> +EXPORT_SYMBOL(devfreq_suspend_device);
>> +
>> +/**
>> + * devfreq_resume_device() - Resume devfreq of a device.
>> + * @devfreq  the devfreq instance to be resumed
>> + */
>> +int devfreq_resume_device(struct devfreq *devfreq)
>> +{
>> +     if (!devfreq)
>> +             return -EINVAL;
>> +
>> +     return devfreq->governor->event_handler(devfreq,
>> +                             DEVFREQ_GOV_RESUME, NULL);
>> +}
>> +EXPORT_SYMBOL(devfreq_resume_device);
>> +
>>  static ssize_t show_governor(struct device *dev,
>>                            struct device_attribute *attr, char *buf)
>>  {
>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>> index bb3aff3..26432ac 100644
>> --- a/drivers/devfreq/governor.h
>> +++ b/drivers/devfreq/governor.h
>> @@ -22,6 +22,8 @@
>>  #define DEVFREQ_GOV_START                    0x1
>>  #define DEVFREQ_GOV_STOP                     0x2
>>  #define DEVFREQ_GOV_INTERVAL                 0x3
>> +#define DEVFREQ_GOV_SUSPEND                  0x4
>> +#define DEVFREQ_GOV_RESUME                   0x5
>>
>>  /* Caution: devfreq->lock must be locked before calling update_devfreq */
>>  extern int update_devfreq(struct devfreq *devfreq);
>> diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
>> index cf94218..a8ba78c 100644
>> --- a/drivers/devfreq/governor_simpleondemand.c
>> +++ b/drivers/devfreq/governor_simpleondemand.c
>> @@ -104,6 +104,15 @@ int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
>>       case DEVFREQ_GOV_INTERVAL:
>>               devfreq_interval_update(devfreq, (unsigned int *)data);
>>               break;
>> +
>> +     case DEVFREQ_GOV_SUSPEND:
>> +             devfreq_monitor_suspend(devfreq);
>> +             break;
>> +
>> +     case DEVFREQ_GOV_RESUME:
>> +             devfreq_monitor_resume(devfreq);
>> +             break;
>> +
>>       default:
>>               break;
>>       }
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 9cdffde..ee243a3 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -158,6 +158,8 @@ extern struct devfreq *devfreq_add_device(struct device *dev,
>>                                 const struct devfreq_governor *governor,
>>                                 void *data);
>>  extern int devfreq_remove_device(struct devfreq *devfreq);
>> +extern int devfreq_suspend_device(struct devfreq *devfreq);
>> +extern int devfreq_resume_device(struct devfreq *devfreq);
>>
>>  /* Helper functions for devfreq user device driver with OPP. */
>>  extern struct opp *devfreq_recommended_opp(struct device *dev,
>> @@ -211,6 +213,16 @@ static int devfreq_remove_device(struct devfreq *devfreq)
>>       return 0;
>>  }
>>
>> +static int devfreq_suspend_device(struct devfreq *devfreq)
>> +{
>> +     return 0;
>> +}
>> +
>> +static int devfreq_resume_device(struct devfreq *devfreq)
>> +{
>> +     return 0;
>> +}
>> +
>>  static struct opp *devfreq_recommended_opp(struct device *dev,
>>                                          unsigned long *freq, u32 flags)
>>  {
>>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.



-- 
Regards,
Rajagopal
--
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