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References: <20210603094944.1114156-1-axel.lin@ingics.com> <1622716791.1034.13.camel@richtek.com>
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From:   Axel Lin <axel.lin@ingics.com>
Date:   Thu, 3 Jun 2021 19:20:57 +0800
Message-ID: <CAFRkauCQ-BTbad8dgDgduDA8QCFTxbocmLxU+sKErUB8WO4bzQ@mail.gmail.com>
Subject: Re: [PATCH] regulator: rt4801: Fix NULL pointer dereference if
 priv->enable_gpios is NULL
To:     =?UTF-8?B?Y3lfaHVhbmco6buD5ZWf5Y6fKQ==?= <cy_huang@richtek.com>
Cc:     "broonie@kernel.org" <broonie@kernel.org>,
        "lgirdwood@gmail.com" <lgirdwood@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) <cy_huang@richtek.com> =E6=96=BC 2021=
=E5=B9=B46=E6=9C=883=E6=97=A5 =E9=80=B1=E5=9B=9B =E4=B8=8B=E5=8D=886:39=E5=
=AF=AB=E9=81=93=EF=BC=9A
>
> Hi, Axel:
>
> Which case will cause this error? I'm not really sure.
> But if devm_gpiod_get_array_optional will return null, then it must be ch=
eck
> earlier in probe function
>
>         priv->enable_gpios =3D devm_gpiod_get_array_optional(&i2c->dev, "=
enable",
> GPIOD_OUT_HIGH);
> -       if (IS_ERR(priv->enable_gpios)) {+       if (IS_ERR_OR_NULL(priv-=
>enable_gpios)) {
>
> If so, this change will be more reasonable.
> Cause in binding document, I already write the min item must be '1'.

Documentation/devicetree/bindings/regulator/richtek,rt4801-regulator.yaml
  enable-gpios:
    description: GPIOs to use to enable DSVP/DSVN regulator.
      The first one is ENP to enable DSVP, and second one is ENM to enable =
DSVN.
      Number of GPIO in the array list could be 1 or 2.
      If only one gpio is specified, only one gpio used to control ENP/ENM.
      Else both are spefied, DSVP/DSVN could be controlled individually.
      Othersie, this property not specified. treat both as always-on regula=
tor.
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this  imply it's optional.

If it's cannot be optional, you should use devm_gpiod_get_array() instead.

Regards,
Axel