Date: Wed, 20 Sep 2017 15:53:01 -0500
From: Rob Herring <robh@kernel.org>
To: Chen Zhong <chen.zhong@mediatek.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Lee Jones <lee.jones@linaro.org>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Eddie Huang <eddie.huang@mediatek.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Andi Shyti <andi.shyti@samsung.com>,
        Jaechul Lee <jcsing.lee@samsung.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>, linux-input@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-rtc@vger.kernel.org
Subject: Re: [PATCH v4 2/5] dt-bindings: input: Add document bindings for
 mtk-pmic-keys
Message-ID: <20170920205301.v6gpmhll4pdpuyxv@rob-hp-laptop>
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On Sun, Sep 17, 2017 at 04:00:49PM +0800, Chen Zhong wrote:
> This patch adds the device tree binding documentation for the MediaTek
> pmic keys found on PMIC MT6397/MT6323.
> 
> Signed-off-by: Chen Zhong <chen.zhong@mediatek.com>
> ---
>  .../devicetree/bindings/input/mtk-pmic-keys.txt    |   41 ++++++++++++++++++++
>  1 file changed, 41 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/mtk-pmic-keys.txt
> 
> diff --git a/Documentation/devicetree/bindings/input/mtk-pmic-keys.txt b/Documentation/devicetree/bindings/input/mtk-pmic-keys.txt
> new file mode 100644
> index 0000000..fd48ff7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/mtk-pmic-keys.txt
> @@ -0,0 +1,41 @@
> +MediaTek MT6397/MT6323 PMIC Keys Device Driver
> +
> +There are two key functions provided by MT6397/MT6323 PMIC, pwrkey
> +and homekey. The key functions are defined as the subnode of the function
> +node provided by MT6397/MT6323 PMIC that is being defined as one kind
> +of Muti-Function Device (MFD)
> +
> +For MT6397/MT6323 MFD bindings see:
> +Documentation/devicetree/bindings/mfd/mt6397.txt
> +
> +Required properties:
> +- compatible: "mediatek,mt6397-keys" or "mediatek,mt6323-keys"
> +- linux,keycodes: Specifies the numeric keycode values to
> +	be used for reporting keys presses. The array can
> +	contain up to 2 entries.
> +
> +Optional Properties:
> +- mediatek,wakeup-keys: Specifies each key can be used as a wakeup source
> +	or not. This can be customized depends on board design.

I think this should be a common property if we're going to put into DT. 
Something like "wakeup-scancodes" to be clear the values are the raw 
scancodes. Alternatively, we could list Linux keycodes instead with 
something like "linux,wakeup-keycodes".

> +- wakeup-source: PMIC keys can be used as wakeup sources.

Just "See ../power/wakeup-source.txt" for the description.

> +- mediatek,long-press-mode: Long press key shutdown setting, 1 for
> +	pwrkey only, 2 for pwrkey/homekey together, others for disabled.
> +- debounce-interval: Long press key shutdown debouncing interval time
> +	in seconds. 0/1/2/3 for 8/11/14/5 seconds. If not specified defaults to 0.

This property units should be in milliseconds. However, this doesn't 
sound like debounce filtering time if 5-14 seconds. That sounds like 
forced power off time (i.e. for a hung device). This also should be 
common. I imagine we already have some drivers with similar properties.

Rob