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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 2 Jun 2022 15:57:19 +0200
Message-ID: <CAHp75Vf=ATRfaaaGFuuPHuQj6wTjnRPBw4W5WYfgYuUP-A-L=g@mail.gmail.com>
Subject: Re: [PATCH 07/14] leds: flashlight: mt6370: Add Mediatek MT6370
 flashlight support
To:     szuni chen <szunichen@gmail.com>
Cc:     ChiaEn Wu <peterwu.pub@gmail.com>,
        Lee Jones <lee.jones@linaro.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>, Pavel Machek <pavel@ucw.cz>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Sebastian Reichel <sre@kernel.org>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        "Krogerus, Heikki" <heikki.krogerus@linux.intel.com>,
        Helge Deller <deller@gmx.de>, cy_huang@richtek.com,
        alice_chen@richtek.com, chiaen_wu@richtek.com,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        USB <linux-usb@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        "open list:FRAMEBUFFER LAYER" <linux-fbdev@vger.kernel.org>
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On Thu, Jun 2, 2022 at 2:07 PM szuni chen <szunichen@gmail.com> wrote:
> Andy Shevchenko <andy.shevchenko@gmail.com> =E6=96=BC 2022=E5=B9=B46=E6=
=9C=881=E6=97=A5 =E9=80=B1=E4=B8=89 =E4=B8=8B=E5=8D=885:57=E5=AF=AB=E9=81=
=93=EF=BC=9A
> > On Tue, May 31, 2022 at 1:32 PM ChiaEn Wu <peterwu.pub@gmail.com> wrote=
:

...

> > > +       const char * const states[] =3D { "off", "keep", "on" };
> > > +       const char *str;
> > > +       int ret;
> > > +
> > > +       if (!fwnode_property_read_string(init_data->fwnode,
> > > +                                        "default-state", &str)) {
> > > +               ret =3D match_string(states, ARRAY_SIZE(states), str)=
;
> > > +               if (ret < 0)
> > > +                       ret =3D STATE_OFF;
> > > +
> > > +               led->default_state =3D ret;
> > > +       }
> >
> > fwnode_property_match_string()?
> Sorry, but I think the use of this function is different from my target.
> I want to read the string of the "default-state" property and figure
> out if the string is in the states array.
> But the fwnode_property_match_string aimed to figure out if the state
> in the property array.
> One is a property array and another one is a state array.

Ah, indeed. Nevertheless you may reduce the code base by doing like
the following (I wonder what your code do if there is no default-state
property):

  led->default_state =3D STATE_OFF; // it's by default off since
kzalloc(), so I don't see why we need this line at all.

  fwnode_property_read_string(init_data->fwnode, "default-state", &str);
  ret =3D match_string(states, ARRAY_SIZE(states), str);
  if (ret >=3D 0)
    led->default_state =3D ret;


--=20
With Best Regards,
Andy Shevchenko