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From:   Chanwoo Choi <cwchoi00@gmail.com>
Date:   Tue, 5 Jan 2021 13:35:15 +0900
Message-ID: <CAGTfZH3Rb8qsT6ZtT9QWb_oU_Nt9z+UaiyWkExo1uzSDKz6g8A@mail.gmail.com>
Subject: Re: [PATCH 30/31] PM / devfreq: exynos: convert to use devm_pm_opp_* API
To:     Yangtao Li <tiny.windzz@gmail.com>
Cc:     MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
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Precedence: bulk

On Sun, Jan 3, 2021 at 12:59 PM Yangtao Li <tiny.windzz@gmail.com> wrote:
>
> Use devm_pm_opp_* API to simplify code, and remove opp_table
> from exynos_bus.
>
> Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> ---
>  drivers/devfreq/exynos-bus.c | 42 ++++++++----------------------------
>  1 file changed, 9 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index e689101abc93..51752e5ce980 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -33,7 +33,6 @@ struct exynos_bus {
>
>         unsigned long curr_freq;
>
> -       struct opp_table *opp_table;
>         struct clk *clk;
>         unsigned int ratio;
>  };
> @@ -159,10 +158,7 @@ static void exynos_bus_exit(struct device *dev)
>
>         platform_device_unregister(bus->icc_pdev);
>
> -       dev_pm_opp_of_remove_table(dev);
>         clk_disable_unprepare(bus->clk);
> -       dev_pm_opp_put_regulators(bus->opp_table);

OPP uses the clock and regulator. It means that there are dependency
between them and the sequence for resource free.

I think that OPP should be removed before clock and regulator.
Your patch always guarantee this dependency? If not, we have to
free the resource according to the dependency.

> -       bus->opp_table = NULL;
>  }
>
>  static void exynos_bus_passive_exit(struct device *dev)
> @@ -171,7 +167,6 @@ static void exynos_bus_passive_exit(struct device *dev)
>
>         platform_device_unregister(bus->icc_pdev);
>
> -       dev_pm_opp_of_remove_table(dev);
>         clk_disable_unprepare(bus->clk);
>  }
>
> @@ -183,15 +178,13 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>         const char *vdd = "vdd";
>         int i, ret, count, size;
>
> -       opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
> +       opp_table = devm_pm_opp_set_regulators(dev, &vdd, 1);
>         if (IS_ERR(opp_table)) {
>                 ret = PTR_ERR(opp_table);
>                 dev_err(dev, "failed to set regulators %d\n", ret);
>                 return ret;
>         }
>
> -       bus->opp_table = opp_table;
> -
>         /*
>          * Get the devfreq-event devices to get the current utilization of
>          * buses. This raw data will be used in devfreq ondemand governor.
> @@ -199,25 +192,20 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>         count = devfreq_event_get_edev_count(dev, "devfreq-events");
>         if (count < 0) {
>                 dev_err(dev, "failed to get the count of devfreq-event dev\n");
> -               ret = count;
> -               goto err_regulator;
> +               return count;
>         }
>         bus->edev_count = count;
>
>         size = sizeof(*bus->edev) * count;
>         bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
> -       if (!bus->edev) {
> -               ret = -ENOMEM;
> -               goto err_regulator;
> -       }
> +       if (!bus->edev)
> +               return -ENOMEM;
>
>         for (i = 0; i < count; i++) {
>                 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
>                                                         "devfreq-events", i);
> -               if (IS_ERR(bus->edev[i])) {
> -                       ret = -EPROBE_DEFER;
> -                       goto err_regulator;
> -               }
> +               if (IS_ERR(bus->edev[i]))
> +                       return -EPROBE_DEFER;
>         }
>
>         /*
> @@ -234,12 +222,6 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
>                 bus->ratio = DEFAULT_SATURATION_RATIO;
>
>         return 0;
> -
> -err_regulator:
> -       dev_pm_opp_put_regulators(bus->opp_table);
> -       bus->opp_table = NULL;
> -
> -       return ret;
>  }
>
>  static int exynos_bus_parse_of(struct device_node *np,
> @@ -264,7 +246,7 @@ static int exynos_bus_parse_of(struct device_node *np,
>         }
>
>         /* Get the freq and voltage from OPP table to scale the bus freq */
> -       ret = dev_pm_opp_of_add_table(dev);
> +       ret = devm_pm_opp_of_add_table(dev);
>         if (ret < 0) {
>                 dev_err(dev, "failed to get OPP table\n");
>                 goto err_clk;
> @@ -276,15 +258,13 @@ static int exynos_bus_parse_of(struct device_node *np,
>         if (IS_ERR(opp)) {
>                 dev_err(dev, "failed to find dev_pm_opp\n");
>                 ret = PTR_ERR(opp);
> -               goto err_opp;
> +               goto err_clk;
>         }
>         bus->curr_freq = dev_pm_opp_get_freq(opp);
>         dev_pm_opp_put(opp);
>
>         return 0;
>
> -err_opp:
> -       dev_pm_opp_of_remove_table(dev);
>  err_clk:
>         clk_disable_unprepare(bus->clk);
>
> @@ -425,7 +405,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
>         /* Parse the device-tree to get the resource information */
>         ret = exynos_bus_parse_of(np, bus);
>         if (ret < 0)
> -               goto err_reg;
> +               return ret;
>
>         if (passive)
>                 ret = exynos_bus_profile_init_passive(bus, profile);
> @@ -456,11 +436,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
>         return 0;
>
>  err:
> -       dev_pm_opp_of_remove_table(dev);
>         clk_disable_unprepare(bus->clk);
> -err_reg:
> -       dev_pm_opp_put_regulators(bus->opp_table);
> -       bus->opp_table = NULL;
>
>         return ret;
>  }
> --
> 2.25.1
>


-- 
Best Regards,
Chanwoo Choi