[v10,3/8] ARM: dt: Binding documentation for imx25 touchscreen controller

Commit Message

Markus Pargmann Dec. 14, 2015, 1:53 p.m. UTC

This is the touchscreen conversion queue binding documentation. It uses
the shared imx25 ADC.

Signed-off-by: Markus Pargmann <[e-mail]>
---

Notes:
    Changes in v9:
     - Updated binding descriptions
    
    Changes in v5:
     - Fix signed/unsigned comparison
     - Fix unused variable settling_time by putting it in the correct argument list
     - Use continous conversion queue with the repeat feature and a proper
       repeat-wait. Previously the touchscreen caused massive number of interrupts.

 .../bindings/input/touchscreen/fsl-mx25-tcq.txt    | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt

Comments

Rob Herring (Arm) Dec. 20, 2015, 3:39 a.m. UTC | #1

On Mon, Dec 14, 2015 at 02:53:49PM +0100, Markus Pargmann wrote:
> This is the touchscreen conversion queue binding documentation. It uses
> the shared imx25 ADC.
> 
> Signed-off-by: Markus Pargmann <[e-mail]>
> ---
> 
> Notes:
>     Changes in v9:
>      - Updated binding descriptions
>     
>     Changes in v5:
>      - Fix signed/unsigned comparison
>      - Fix unused variable settling_time by putting it in the correct argument list
>      - Use continous conversion queue with the repeat feature and a proper
>        repeat-wait. Previously the touchscreen caused massive number of interrupts.
> 
>  .../bindings/input/touchscreen/fsl-mx25-tcq.txt    | 35 ++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt

Acked-by: Rob Herring <[e-mail]>
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Patch

diff --git a/Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt b/Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt
new file mode 100644
index 000000000000..cdf05f9b2329
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/fsl-mx25-tcq.txt
@@ -0,0 +1,35 @@ 
+Freescale mx25 TS conversion queue module
+
+mx25 touchscreen conversion queue module which controls the ADC unit of the
+mx25 for attached touchscreens.
+
+Required properties:
+ - compatible: Should be "fsl,imx25-tcq".
+ - reg: Memory range of the device.
+ - interrupts: Should be the interrupt number associated with this module within
+   the tscadc unit (<0>).
+ - interrupt-parent: Should be a phandle to the tscadc unit.
+ - fsl,wires: Should be '<4>' or '<5>'
+
+Optional properties:
+ - fsl,pen-debounce-ns: Pen debounce time in nanoseconds.
+ - fsl,pen-threshold: Pen-down threshold for the touchscreen. This is a value
+   between 1 and 4096. It is the ratio between the internal reference voltage
+   and the measured voltage after the plate was precharged. Resistence between
+   plates and therefore the voltage decreases with pressure so that a smaller
+   value is equivalent to a higher pressure.
+ - fsl,settling-time-ns: Settling time in nanoseconds. The settling time is before
+   the actual touch detection to wait for an even charge distribution in the
+   plate.
+
+This device includes two conversion queues which can be added as subnodes.
+The first queue is for the touchscreen, the second for general purpose ADC.
+
+Example:
+	tsc: tcq@50030400 {
+		compatible = "fsl,imx25-tcq";
+		reg = <0x50030400 0x60>;
+		interrupt-parent = <&tscadc>;
+		interrupts = <0>;
+		fsl,wires = <4>;
+	};