> This patch adds suspend and resume apis needed
> for devices which can idle. Suspend/resume apis
> are called from driver to suspend/resume devfreq
> load monitoring of that device.
>
> Signed-off-by: Rajagopal Venkat <rajagopal.ven...@linaro.org>
1. Some devfreq devices may need their own code to do suspend/resume; e.g.,
setting a specific frequency for suspend (especially with suspend-to-RAM).
2. Are these new APIs (devfreq_suspend/resume_device()) intended to be
used by runtime_pm and pm(Suspend-to-RAM) callbacks of the parent devices?
If so, could you consider use the structure of runtime-pm (I don't have
an idea on how to do this for now)? For example, when a device is being
suspended, devfreq device's suspend is also called without calling it
explicitly at the device driver's suspend callback.
3. As in the patch 1/3, could you consider to integrate class-wide
features in devfreq.c, not in a governor?
Cheers!
MyungJoo
> ---
> drivers/devfreq/devfreq.c | 30 ++++++++++++++++++++++++++++++
> drivers/devfreq/governor_simpleondemand.c | 15 +++++++++++++++
> include/linux/devfreq.h | 16 ++++++++++++++++
> 3 files changed, 61 insertions(+)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 5aa23a8..375b5aa1 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -233,6 +233,36 @@ 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;
> +
> + devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_SUSPEND);
> +
> + return 0;
> +}
> +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;
> +
> + devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_RESUME);
> +
> + return 0;
> +}
> +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_simpleondemand.c
> b/drivers/devfreq/governor_simpleondemand.c
> index 7c70c30..95e4db9 100644
> --- a/drivers/devfreq/governor_simpleondemand.c
> +++ b/drivers/devfreq/governor_simpleondemand.c
> @@ -221,6 +221,21 @@ static int devfreq_simple_ondemand_func(struct devfreq
> *df,
> ondemand_exit(df);
> break;
>
> + case DEVFREQ_GOV_SUSPEND:
> + if (delayed_work_pending(&data->work)) {
> + data->stop_queuing = true;
> + cancel_delayed_work_sync(&data->work);
> + }
> + break;
> +
> + case DEVFREQ_GOV_RESUME:
> + if (!delayed_work_pending(&data->work)) {
> + data->stop_queuing = false;
> + queue_delayed_work(devfreq_wq, &data->work,
> + msecs_to_jiffies(df->profile->polling_ms));
> + }
> + break;
> +
> case DEVFREQ_GOV_LIMITS:
> if (delayed_work_pending(&data->work)) {
> mutex_lock(&df->lock);
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 600cc2e..7c6517f 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -56,6 +56,8 @@ struct devfreq_dev_status {
> #define DEVFREQ_GOV_START 0x1
> #define DEVFREQ_GOV_STOP 0x2
> #define DEVFREQ_GOV_LIMITS 0x3
> +#define DEVFREQ_GOV_SUSPEND 0x4
> +#define DEVFREQ_GOV_RESUME 0x5
>
> /**
> * struct devfreq_dev_profile - Devfreq's user device profile
> @@ -155,6 +157,10 @@ extern struct devfreq *devfreq_add_device(struct device
> *dev,
> 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,
> unsigned long *freq, u32 flags);
> @@ -207,6 +213,16 @@ static int devfreq_remove_device(struct devfreq *devfreq)
> return 0;
> }
>
> +static int devfreq_suspend_device(struct devfreq *devfreq)
> +{
> + return 0;
> +}
> +
> +extern int devfreq_resume_device(struct devfreq *devfreq)
> +{
> + return 0;
> +}
> +
> static struct opp *devfreq_recommended_opp(struct device *dev,
> unsigned long *freq, u32 flags)
> {
> --
> 1.7.11.3
>
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