Hi Dmitry,

On Mon, Oct 30, 2017 at 04:06:58PM -0700, Dmitry Torokhov wrote:

Hi Ludovic,

On Fri, Oct 20, 2017 at 03:31:17PM +0200, Ludovic Desroches wrote:

quoted

Add description of the Atmel PTC subsystem bindings.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/input/atmel,ptc.txt        | 67 ++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/atmel,ptc.txt

diff --git a/Documentation/devicetree/bindings/input/atmel,ptc.txt b/Documentation/devicetree/bindings/input/atmel,ptc.txt
new file mode 100644
index 000000000000..a183fd511e04
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/atmel,ptc.txt

@@ -0,0 +1,67 @@
+Atmel PTC Subsystem
+
+The Atmel Peripheral Touch Controller subsystem offers built-in hardware
+for capacitive touch measurement on sensors that function as buttons, sliders
+and wheels.
+
+1) PTC Subsystem node
+
+Required properties:
+- compatible: 		Must be "atmel,sama5d2-ptc"
+- reg: 			Address, length of the shared memory and ppp registers location
+			and length.
+- clocks: 		Phandlers to the clocks.
+- clock-names: 		Must be "ptc_clk", "ptc_int_osc", "slow_clk".
+- #address-cells:	Must be one. The cell is the button or scroller id.
+- #size-cells: 		Must be zero.
+
+Example:
+	ptc@fc060000 {
+		compatible = "atmel,sama5d2-ptc";
+		reg = <0x00800000 0x10000
+		       0xfc060000 0xcf>;
+		interrupts = <58 IRQ_TYPE_LEVEL_HIGH 7>;
+		clocks = <&ptc_clk>, <&main>, <&clk32k>;
+		clock-names = "ptc_clk", "ptc_int_osc", "slow_clk";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		[ child node definitions... ]
+	};
+
+2) Scroller / buttons subnodes
+
+Subnodes describe the kind of sensors the customer want to use. They have to be
+named according to their function: button, slider or wheel.

I wonder do we really need this? Or we can have a generic:

	slider@0 {
		reg = <0>;
		linux,type = <EV_ABS>;
		linux,code = <ABS_X>;
	},
	vertical-slider@1 {
		reg = <1>;
		linux,type = <EV_ABS>;
		linux,code = <ABS_Y>;
	},
	wheel@2 {
		reg = <2>;
		linux,type = <EV_ABS>;
		linux,code = <ABS_WHEEL>;
	},
	button@3 {
		reg = <3>;
		linux,type = <EV_KEY>;
		linux,code = <KEY_A>;
	},
	...

I.e. you specify type/code in a generic way.

No problem with this approach, I can retrieve the kind of sensors from
the linux,type property.

Can I set both ABS_X and ABS_Y? In the future, we may have a "surface"
object reporting coordinates for these axes. It seems there are no
generic helpers to parse the 'linux,code' property, so I assume it won't be a
problem.

Regards

Ludovic