Message-ID: <1506148695.19409.10.camel@mhfsdcap03>
Subject: Re: [PATCH v4 2/5] dt-bindings: input: Add document bindings for
 mtk-pmic-keys
From: Chen Zhong <chen.zhong@mediatek.com>
To: Rob Herring <robh@kernel.org>
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>
Date: Sat, 23 Sep 2017 14:38:15 +0800
In-Reply-To: <20170920205301.v6gpmhll4pdpuyxv@rob-hp-laptop>
References: <1505635252-27716-1-git-send-email-chen.zhong@mediatek.com>
         <1505635252-27716-3-git-send-email-chen.zhong@mediatek.com>
         <20170920205301.v6gpmhll4pdpuyxv@rob-hp-laptop>
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On Wed, 2017-09-20 at 15:53 -0500, Rob Herring wrote:
> 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.

Hi Rob,

I searched in kernel documents and found a similar usage in
"ti,palmas-pwrbutton.txt"
"- ti,palmas-long-press-seconds: Duration in seconds which the power
  button should be kept pressed for Palmas to power off automatically."

Could I just wrote it like this?
mediatek,long-press-seconds = <0>;

And for the wakeup source part, how about Dmitry's suggestion? 
The whole device node would be:

mt6397keys: mt6397keys {
	compatible = "mediatek,mt6397-keys";
	mediatek,long-press-mode = <1>;
	mediatek,long-press-seconds = <0>;
	
	power@0 {
		linux,code = <116>;
		wakeup-source;
	};

	home@0 {
		linux,code = <114>;
	};
};

Thank you.

> 
> Rob