linux-kernel - Re: [PATCH] devfreq: rk3399_dmc: Fix duplicated opp table on reload.

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Date:   Sun, 17 Jun 2018 12:23:13 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>, kernel@...labora.com,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH] devfreq: rk3399_dmc: Fix duplicated opp table on reload.

Hi Enric,

2018-06-16 0:12 GMT+09:00 Enric Balletbo i Serra <enric.balletbo@...labora.com>:
> The opp table is not removed when the driver is unloaded neither when
> there is an error within probe, so if the driver is reloaded the opp
> core shows the following warning:
>
>   rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
>                200000000, volt: 900000, enabled: 1. New: freq: 200000000,
>                volt: 900000, enabled: 1
>   rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
>                400000000, volt: 900000, enabled: 1. New: freq: 400000000,
>                volt: 900000, enabled: 1
>   rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
>                666000000, volt: 900000, enabled: 1. New: freq: 666000000,
>                volt: 900000, enabled: 1
>   rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
>                800000000, volt: 900000, enabled: 1. New: freq: 800000000,
>                volt: 900000, enabled: 1
>   rk3399-dmc-freq dmc: _opp_add: duplicate OPPs detected. Existing: freq:
>                928000000, volt: 900000, enabled: 1. New: freq: 928000000,
>                volt: 900000, enabled: 1
>
> This patch fixes the error path in the probe function and adds a .remove
> function to properly cleanup the opp table on unloading.
>
> Fixes: 5a893e31a636c (PM / devfreq: rockchip: add devfreq driver for rk3399 dmc)
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> ---
>
>  drivers/devfreq/rk3399_dmc.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
> index d5c03e5abe13..e795ad2b3f6b 100644
> --- a/drivers/devfreq/rk3399_dmc.c
> +++ b/drivers/devfreq/rk3399_dmc.c
> @@ -375,8 +375,10 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
>         data->rate = clk_get_rate(data->dmc_clk);
>
>         opp = devfreq_recommended_opp(dev, &data->rate, 0);
> -       if (IS_ERR(opp))
> -               return PTR_ERR(opp);
> +       if (IS_ERR(opp)) {
> +               ret = PTR_ERR(opp);
> +               goto err_free_opp;
> +       }
>
>         data->rate = dev_pm_opp_get_freq(opp);
>         data->volt = dev_pm_opp_get_voltage(opp);
> @@ -388,13 +390,33 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
>                                            &rk3399_devfreq_dmc_profile,
>                                            DEVFREQ_GOV_SIMPLE_ONDEMAND,
>                                            &data->ondemand_data);
> -       if (IS_ERR(data->devfreq))
> -               return PTR_ERR(data->devfreq);
> +       if (IS_ERR(data->devfreq)) {
> +               ret = PTR_ERR(data->devfreq);
> +               goto err_free_opp;
> +       }
> +
>         devm_devfreq_register_opp_notifier(dev, data->devfreq);
>
>         data->dev = dev;
>         platform_set_drvdata(pdev, data);
>
> +       return 0;

It looks strange. Because rk3399_dmcfreq_probe() already include
'return 0' when success.
What is the base commit of this patch?

[snip]

Anyway, if probe fail, device driver have to remove registered OPP table.
Looks good to me.

Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics