linux-kernel - Re: [PATCH v6 3/3] PM / devfreq: Add required OPPs support to passive governor

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Message-ID: <20210204112246.yewojjxv7sy3bhky@vireshk-i7>
Date:   Thu, 4 Feb 2021 16:52:46 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     Viresh Kumar <vireshk@...nel.org>, linux-pm@...r.kernel.org,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        linux-kernel@...r.kernel.org,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Saravana Kannan <saravanak@...gle.com>
Subject: Re: [PATCH v6 3/3] PM / devfreq: Add required OPPs support to
 passive governor

On 04-02-21, 16:14, Hsin-Yi Wang wrote:
> From: Saravana Kannan <saravanak@...gle.com>
> 
> Look at the required OPPs of the "parent" device to determine the OPP that
> is required from the slave device managed by the passive governor. This
> allows having mappings between a parent device and a slave device even when
> they don't have the same number of OPPs.
> 
> Signed-off-by: Saravana Kannan <saravanak@...gle.com>
> Acked-by: MyungJoo Ham <myungjoo.ham@...sung.com>
> Acked-by: Chanwoo Choi <cw00.choi@...sung.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
> ---
>  drivers/devfreq/governor_passive.c | 25 ++++++++++++++++++-------
>  1 file changed, 18 insertions(+), 7 deletions(-)

I have made changes to this patch as well, though I didn't wanted to
do initially :)

diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
index 8fd51cc9b991..b094132bd20b 100644
--- a/drivers/devfreq/governor_passive.c
+++ b/drivers/devfreq/governor_passive.c
@@ -19,18 +19,16 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
                        = (struct devfreq_passive_data *)devfreq->data;
        struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
        unsigned long child_freq = ULONG_MAX;
-       struct dev_pm_opp *opp, *p_opp = ERR_PTR(-ENODEV);
-       int i, count, ret = 0;
+       struct dev_pm_opp *opp, *p_opp;
+       int i, count;
 
        /*
         * If the devfreq device with passive governor has the specific method
         * to determine the next frequency, should use the get_target_freq()
         * of struct devfreq_passive_data.
         */
-       if (p_data->get_target_freq) {
-               ret = p_data->get_target_freq(devfreq, freq);
-               return ret;
-       }
+       if (p_data->get_target_freq)
+               return p_data->get_target_freq(devfreq, freq);
 
        /*
         * If the parent and passive devfreq device uses the OPP table,
@@ -56,35 +54,35 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
         * list of parent device. Because in this case, *freq is temporary
         * value which is decided by ondemand governor.
         */
-       p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
-       if (IS_ERR(p_opp)) {
-               ret = PTR_ERR(p_opp);
-               return ret;
-       }
-
        if (devfreq->opp_table && parent_devfreq->opp_table) {
+               p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent,
+                                               freq, 0);
+               if (IS_ERR(p_opp))
+                       return PTR_ERR(p_opp);
+
                opp = dev_pm_opp_xlate_required_opp(parent_devfreq->opp_table,
                                                    devfreq->opp_table, p_opp);
-               if (!IS_ERR(opp)) {
-                       *freq = dev_pm_opp_get_freq(opp);
-                       dev_pm_opp_put(opp);
-               } else
-                       ret = PTR_ERR(opp);
-               goto out;
+               dev_pm_opp_put(p_opp);
+
+               if (IS_ERR(opp))
+                       return PTR_ERR(opp);
+
+               *freq = dev_pm_opp_get_freq(opp);
+               dev_pm_opp_put(opp);
+
+               return 0;
        }
 
        /*
-        * Get the OPP table's index of decided freqeuncy by governor
+        * Get the OPP table's index of decided frequency by governor
         * of parent device.
         */
        for (i = 0; i < parent_devfreq->profile->max_state; i++)
                if (parent_devfreq->profile->freq_table[i] == *freq)
                        break;
 
-       if (i == parent_devfreq->profile->max_state) {
-               ret = -EINVAL;
-               goto out;
-       }
+       if (i == parent_devfreq->profile->max_state)
+               return -EINVAL;
 
        /* Get the suitable frequency by using index of parent device. */
        if (i < devfreq->profile->max_state) {
@@ -97,10 +95,7 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
        /* Return the suitable frequency for passive device. */
        *freq = child_freq;
 
-out:
-       dev_pm_opp_put(p_opp);
-
-       return ret;
+       return 0;
 }
 
 static int devfreq_passive_notifier_call(struct notifier_block *nb,


-- 
viresh