Re: [PATCH v4 2/3] input: Add DT binding documentation for Colibri VF50 touchscreen

[maitysanchayan@gmail.com]

On 15-08-22 18:36:54, Stefan Agner wrote:
> On 2015-08-21 06:26, Sanchayan Maity wrote:
> > This adds device tree binding documentation for the Colibri VF50
> > touchscreen driver.
> > 
> > Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> > ---
> >  .../bindings/input/touchscreen/colibri-vf50-ts.txt | 36 ++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/input/touchscreen/colibri-vf50-ts.txt
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/input/touchscreen/colibri-vf50-ts.txt
> > b/Documentation/devicetree/bindings/input/touchscreen/colibri-vf50-ts.txt
> > new file mode 100644
> > index 0000000..e615aa9
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/colibri-vf50-ts.txt
> > @@ -0,0 +1,36 @@
> > +* Toradex Colibri VF50 Touchscreen driver
> > +
> > +Required Properties:
> > +- compatible must be toradex,vf50-touchscreen
> > +- io-channels: adc channels being used by the Colibri VF50 module
> > +- xp-gpios: FET gate driver for input of X+
> > +- xm-gpios: FET gate driver for input of X-
> > +- yp-gpios: FET gate driver for input of Y+
> > +- ym-gpios: FET gate driver for input of Y-
> > +- interrupt-parent: phandle for the interrupt controller
> > +- interrupts: pen irq interrupt for touch detection
> 
> I like the use of the interrupt interface for the touch detection pin.
> Maybe you can mention here that this is (typically) a GPIO...
> 
> > +- pinctrl-names: "idle", "default", "gpios"
> > +- pinctrl-0: pinctrl node for idle state gpio pinmux
> > +- pinctrl-1: pinctrl node for touch detection state pinmux
> 
> "touch detection" for default is rather confusing or even wrong. The
> Idle state is used for pen/touch detection, default is used for X/Y and
> Pressure measurement (maybe better described as touch measurement).

Ok. Understood. I see how my wordings can create confusion or are
misleading. Will fix.

- Sanchayan.

> 
> > +- pinctrl-2: pinctrl node for gpios functioning as FET gate drivers
> > +- vf50-ts-min-pressure: pressure level at which to stop measuring X/Y values
> > +
> > +Example:
> > +
> > +	touchctrl: vf50_touchctrl {
> > +		compatible = "toradex,vf50-touchscreen";
> > +		io-channels = <&adc1 0>,<&adc0 0>,
> > +				<&adc0 1>,<&adc1 2>;
> > +		xp-gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
> > +		xm-gpios = <&gpio2 29 GPIO_ACTIVE_HIGH>;
> > +		yp-gpios = <&gpio0 12 GPIO_ACTIVE_LOW>;
> > +		ym-gpios = <&gpio0 4 GPIO_ACTIVE_HIGH>;
> > +		interrupt-parent = <&gpio0>;
> > +		interrupts = <8 IRQ_TYPE_LEVEL_LOW>;
> > +		pinctrl-names = "idle","default","gpios";
> > +		pinctrl-0 = <&pinctrl_touchctrl_idle>;
> > +		pinctrl-1 = <&pinctrl_touchctrl_default>;
> > +		pinctrl-2 = <&pinctrl_touchctrl_gpios>;
> > +		vf50-ts-min-pressure = <200>;
> > +		status = "disabled";
> > +	};
> 
> Otherwise I agree with 1 and 2:
> 
> Acked-by: Stefan Agner <stefan@agner.ch>
> 
> --
> Stefan
>