On Mon, Jan 25, 2016 at 07:04:37PM -0800, Stefan Agner wrote:
> Add device tree support for the I2C variant of AD7879 (AD7879-1). This
> allows to specify the touchscreen controller as a I2C client node.
> Most of the options available as platform data are also available as
> device tree properties. Exporting the GPIO is currently not possible
> through device tree.
>
> Signed-off-by: Stefan Agner <ste...@agner.ch>
> ---
> .../bindings/input/touchscreen/ad7879-i2c.txt | 47 ++++++++++++++++
> drivers/input/touchscreen/ad7879-i2c.c | 63
> +++++++++++++++++++++-
> drivers/input/touchscreen/ad7879-spi.c | 3 +-
> drivers/input/touchscreen/ad7879.c | 2 +-
> drivers/input/touchscreen/ad7879.h | 1 +
> 5 files changed, 113 insertions(+), 3 deletions(-)
> create mode 100644
> Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
>
> diff --git
> a/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
> b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
> new file mode 100644
> index 0000000..bf169a2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/touchscreen/ad7879-i2c.txt
> @@ -0,0 +1,47 @@
> +* Analog Devices AD7879-1/AD7889-1 touchscreen interface (I2C)
> +
> +Required properties:
> +- compatible: must be "adi,ad7879-1"
> +- reg: i2c slave address
> +- interrupt-parent: the phandle for the interrupt controller
> +- interrupts: touch controller interrupt
> +- resistance-plate-x : total resistance of X-plate (for pressure
> + calculation)
> +- touchscreen-max-pressure : maximum reported pressure
> +- touchscreen-swapped-x-y : X and Y axis are swapped (boolean)
> + Swapping is done after inverting the axis
> +Optional properties:
> +- first-conversion-delay : 0-12 in 128us steps (starting with 128us)
> + 13: 2.560ms
> + 14: 3.584ms
> + 15: 4.096ms
> +- acquisition-time : 0: 2us
> + 1: 4us
> + 2: 8us
> + 3: 16us
> +- median-filter-size : 0: disabled
> + 1: 4 measurements
> + 2: 8 measurements
> + 3: 16 measurements
> +- averaging : 0: 2 middle values (1 if median disabled)
> + 1: 4 middle values
> + 2: 8 middle values
> + 3: 16 values
> +- conversion-interval: : 0: convert one time only
> + 1-255: 515us + val * 35us (up to 9.440ms)
These all should be prefixed with "adi,". Also, please state the sizes
are 8-bit.
> +
> +Example:
> +
> + ad7879@2c {
> + compatible = "adi,ad7879-1";
> + reg = <0x2c>;
> + interrupt-parent = <&gpio1>;
> + interrupts = <13 IRQ_TYPE_EDGE_FALLING>;
> + resistance-plate-x = <120>;
> + touchscreen-max-pressure = <4096>;
> + first-conversion-delay = /bits/ 8 <3>;
> + acquisition-time = /bits/ 8 <1>;
> + median-filter-size = /bits/ 8 <2>;
> + averaging = /bits/ 8 <1>;
> + conversion-interval = /bits/ 8 <255>;
> + };
