[PATCH v4 2/5] dt-bindings: input: Add document bindings for mtk-pmic-keys

[Chen Zhong]

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 at 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 at 0 {
		linux,code = <116>;
		wakeup-source;
	};

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

Thank you.

> 
> Rob