linux-kernel - Re: [PATCH] soc: amlogic: meson-pwrc: Hold reference returned by of_get

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Message-ID: <CAFBinCC1x-655H2LbbUhiVGmgXL+tdSRnCPV0a-NJcZKOFJZuw@mail.gmail.com>
Date:   Mon, 25 Jul 2022 21:46:30 +0200
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     Liang He <windhl@....com>
Cc:     Neil Armstrong <narmstrong@...libre.com>, khilman@...libre.com,
        jbrunet@...libre.com, inux-amlogic@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: amlogic: meson-pwrc: Hold reference returned by of_get_parent()

Hello,

thank you for your patch!

On Tue, Jul 5, 2022 at 4:20 AM Liang He <windhl@....com> wrote:
[...]
> +       struct device_node *np;
>
>         int i, ret;
>
>         match = of_device_get_match_data(&pdev->dev);
> @@ -495,7 +496,9 @@ static int meson_ee_pwrc_probe(struct platform_device *pdev)
>
>         pwrc->xlate.num_domains = match->count;
>
> -       regmap_hhi = syscon_node_to_regmap(of_get_parent(pdev->dev.of_node));
> +       np = of_get_parent(pdev->dev.of_node);
> +       regmap_hhi = syscon_node_to_regmap(np);
This works but I had to read the code twice because I thought the
wrong struct device_node was used.
Other drivers typically use "np" for whatever the code section
currently refers to. In this case the code section is about the power
controller, so I thought that "np" was the same as
"pdev->dev.of_node".

I think the code would be easier to understand and the likelihood of
someone making the same mistake as I did if you could rename "np" to
"parent_np" (just like you have done in your other patches).

[...]
> +       struct device_node *np;
same as above, I suggest renaming this to parent_np.