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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 25 Jul 2022 10:55:00 +0200
Message-ID: <CAHp75VfgiK87VwWu2bTJ_mR0=g0sa0LPJ+H16OGcUdARmzFRSA@mail.gmail.com>
Subject: Re: [PATCH v6 12/13] leds: flash: mt6370: Add MediaTek MT6370
 flashlight support
To:     ChiaEn Wu <peterwu.pub@gmail.com>
Cc:     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>,
        ChiaEn Wu <chiaen_wu@richtek.com>,
        Alice Chen <alice_chen@richtek.com>,
        cy_huang <cy_huang@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>,
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        szuni chen <szunichen@gmail.com>
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On Fri, Jul 22, 2022 at 12:25 PM ChiaEn Wu <peterwu.pub@gmail.com> wrote:

Forgot to add a couple of things...

...

> +#define MT6370_ITORCH_MIN_UA           25000
> +#define MT6370_ITORCH_STEP_UA          12500
> +#define MT6370_ITORCH_MAX_UA           400000
> +#define MT6370_ITORCH_DOUBLE_MAX_UA    800000
> +#define MT6370_ISTRB_MIN_UA            50000
> +#define MT6370_ISTRB_STEP_UA           12500
> +#define MT6370_ISTRB_MAX_UA            1500000
> +#define MT6370_ISTRB_DOUBLE_MAX_UA     3000000

Perhaps _uA would be better and consistent across your series
regarding current units.

...

> +       /*
> +        * For the flash to turn on/off, need to wait HW ramping up/down time

we need

> +        * 5ms/500us to prevent the unexpected problem.
> +        */
> +       if (!prev && curr)
> +               usleep_range(5000, 6000);
> +       else if (prev && !curr)
> +               udelay(500);

This still remains unanswered, why in the first place we allow
switching, and a busy loop in the other place?

-- 
With Best Regards,
Andy Shevchenko