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Message-id: <58219B96.6060106@samsung.com>
Date: Tue, 08 Nov 2016 18:32:06 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: Lin Huang <hl@...k-chips.com>, myungjoo.ham@...sung.com
Cc: dianders@...omium.org, linux-rockchip@...ts.infradead.org,
linux-pm@...r.kernel.org, dbasehore@...omium.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] PM/devfreq: add suspend frequency support
Hi Lin,
On 2016년 11월 08일 18:11, Lin Huang wrote:
> Add suspend frequency support and if needed set it to
> the frequency obtained from the suspend opp (can be defined
> using opp-v2 bindings and is optional).
>
> Signed-off-by: Lin Huang <hl@...k-chips.com>
> ---
> Changes in v2:
> - use update_devfreq() instead devfreq_update_status()
> Changes in v3:
> - fix build error
> Changes in v4:
> - move dev_pm_opp_get_suspend_opp() to devfreq_add_device()
>
> drivers/devfreq/devfreq.c | 15 +++++++++++++--
> drivers/devfreq/governor_simpleondemand.c | 9 +++++++++
> include/linux/devfreq.h | 9 +++++++++
> 3 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index bf3ea76..d9d56e1 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -363,7 +363,10 @@ void devfreq_monitor_suspend(struct devfreq *devfreq)
> mutex_unlock(&devfreq->lock);
> return;
> }
> -
> + if (devfreq->suspend_freq) {
> + update_devfreq(devfreq);
> + devfreq->suspend_flag = true;
You don't need the additional variable (devfreq->suspend_flag).
When adding the devfreq on devfreq_add_device(),
you can initialize the devfreq->suspend_freq as zero(0).
You can check whether devfreq->suspend_freq is 0 or not
without the new suspend_flag.
> + }
> devfreq_update_status(devfreq, devfreq->previous_freq);
> devfreq->stop_polling = true;
> mutex_unlock(&devfreq->lock);
> @@ -394,7 +397,8 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>
> devfreq->last_stat_updated = jiffies;
> devfreq->stop_polling = false;
> -
> + if (devfreq->suspend_freq)
> + devfreq->suspend_flag = false;
ditto. You don't need to add this code.
> if (devfreq->profile->get_cur_freq &&
> !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
> devfreq->previous_freq = freq;
> @@ -528,6 +532,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
> struct devfreq *devfreq;
> struct devfreq_governor *governor;
> int err = 0;
> + struct dev_pm_opp *suspend_opp;
>
> if (!dev || !profile || !governor_name) {
> dev_err(dev, "%s: Invalid parameters.\n", __func__);
> @@ -563,6 +568,12 @@ struct devfreq *devfreq_add_device(struct device *dev,
> devfreq->data = data;
> devfreq->nb.notifier_call = devfreq_notifier_call;
>
> + rcu_read_lock();
> + suspend_opp = dev_pm_opp_get_suspend_opp(dev);
> + if (suspend_opp)
> + devfreq->suspend_freq = dev_pm_opp_get_freq(suspend_opp);
> + rcu_read_unlock();
> +
> if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
> mutex_unlock(&devfreq->lock);
> devfreq_set_freq_table(devfreq);
> diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
> index ae72ba5..84b3ce1 100644
> --- a/drivers/devfreq/governor_simpleondemand.c
> +++ b/drivers/devfreq/governor_simpleondemand.c
> @@ -29,6 +29,15 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
> struct devfreq_simple_ondemand_data *data = df->data;
> unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
>
> + /*
> + * if devfreq in suspend status and have suspend_freq,
> + * the frequency need to set to suspend_freq
> + */
> + if (df->suspend_flag) {
> + *freq = df->suspend_freq;
> + return 0;
> + }
You can check it as following:
if (df->suspend_freq != 0)
*freq = df->suspend_freq;
> +
> err = devfreq_update_stats(df);
> if (err)
> return err;
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 2de4e2e..c463ae1 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -172,6 +172,7 @@ struct devfreq {
> struct delayed_work work;
>
> unsigned long previous_freq;
> + unsigned long suspend_freq;
> struct devfreq_dev_status last_status;
>
> void *data; /* private data for governors */
> @@ -179,6 +180,7 @@ struct devfreq {
> unsigned long min_freq;
> unsigned long max_freq;
> bool stop_polling;
> + bool suspend_flag;
You don't need to add new variable.
>
> /* information for device frequency transition */
> unsigned int total_trans;
> @@ -214,6 +216,8 @@ extern int devfreq_resume_device(struct devfreq *devfreq);
> /* Helper functions for devfreq user device driver with OPP. */
> extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
> unsigned long *freq, u32 flags);
> +extern void devfreq_opp_get_suspend_opp(struct device *dev,
> + struct devfreq *devfreq);
Why do you need this function? Also, this patch don't include the body
of devfreq_opp_get_suspend_opp() function.
> extern int devfreq_register_opp_notifier(struct device *dev,
> struct devfreq *devfreq);
> extern int devfreq_unregister_opp_notifier(struct device *dev,
> @@ -348,6 +352,11 @@ static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
> return ERR_PTR(-EINVAL);
> }
>
> +static inline void devfreq_opp_get_suspend_opp(struct device *dev,
> + struct devfreq *devfreq)
> +{
> +}
> +
> static inline int devfreq_register_opp_notifier(struct device *dev,
> struct devfreq *devfreq)
> {
>
--
Best Regards,
Chanwoo Choi
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