Date:   Wed, 6 Jan 2021 04:59:04 +0900
From:   Chanwoo Choi <cwchoi00@...il.com>
To:     Yangtao Li <tiny.windzz@...il.com>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
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Subject: Re: [PATCH 28/31] PM / devfreq: imx8m-ddrc: convert to use
 devm_pm_opp_* API

Hi Yangtao,

On Tue, Jan 5, 2021 at 1:13 PM Chanwoo Choi <cwchoi00@...il.com> wrote:
>
> On Sun, Jan 3, 2021 at 12:58 PM Yangtao Li <tiny.windzz@...il.com> wrote:
> >
> > Use devm_pm_opp_* API to simplify code.
> >
> > Signed-off-by: Yangtao Li <tiny.windzz@...il.com>
> > ---
> >  drivers/devfreq/imx8m-ddrc.c | 15 ++-------------
> >  1 file changed, 2 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/devfreq/imx8m-ddrc.c b/drivers/devfreq/imx8m-ddrc.c
> > index bc82d3653bff..9383d6e5538b 100644
> > --- a/drivers/devfreq/imx8m-ddrc.c
> > +++ b/drivers/devfreq/imx8m-ddrc.c
> > @@ -370,11 +370,6 @@ static int imx8m_ddrc_check_opps(struct device *dev)
> >         return 0;
> >  }
> >
> > -static void imx8m_ddrc_exit(struct device *dev)
> > -{
> > -       dev_pm_opp_of_remove_table(dev);
> > -}
> > -
> >  static int imx8m_ddrc_probe(struct platform_device *pdev)
> >  {
> >         struct device *dev = &pdev->dev;
> > @@ -419,7 +414,7 @@ static int imx8m_ddrc_probe(struct platform_device *pdev)
> >                 return ret;
> >         }
> >
> > -       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");
> >                 return ret;
> > @@ -427,12 +422,11 @@ static int imx8m_ddrc_probe(struct platform_device *pdev)
> >
> >         ret = imx8m_ddrc_check_opps(dev);
> >         if (ret < 0)
> > -               goto err;
> > +               return ret;
> >
> >         priv->profile.polling_ms = 1000;
> >         priv->profile.target = imx8m_ddrc_target;
> >         priv->profile.get_dev_status = imx8m_ddrc_get_dev_status;
> > -       priv->profile.exit = imx8m_ddrc_exit;
> >         priv->profile.get_cur_freq = imx8m_ddrc_get_cur_freq;
> >         priv->profile.initial_freq = clk_get_rate(priv->dram_core);
> >
> > @@ -441,13 +435,8 @@ static int imx8m_ddrc_probe(struct platform_device *pdev)
> >         if (IS_ERR(priv->devfreq)) {
> >                 ret = PTR_ERR(priv->devfreq);
> >                 dev_err(dev, "failed to add devfreq device: %d\n", ret);
> > -               goto err;
> >         }
> >
> > -       return 0;
> > -
> > -err:
> > -       dev_pm_opp_of_remove_table(dev);
> >         return ret;
>
> devm_devfreq_add_device() doesn't return any integer value.
> Even if devm_devfreq_add_device() returns the right devfreq instance,
> the 'ret' value  is not the return value of  devm_devfreq_add_device().
>
> On this patch, 'ret' value of 'return ret' is from imx8m_ddrc_check_opps().
> Surely, it is well working with this modification. But, it is not code
> for exception handling.
> So, we need to remain the following codes:
>
>     return 0;
> err:
>     return ret;
>

'err' is not necessary. You better to edit it as following:

if (IS_ERR(priv->devfreq)) {
    dev_err(dev, "failed to add devfreq device: %d\n", ret);
    return PTR_ERR(priv->devfreq);
}

return 0;

-- 
Best Regards,
Chanwoo Choi

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