Re: [PATCH 1/2] dt-bindings: input: touchscreen: iqs5xx: Add bindings

[Rob Herring <robh@kernel.org>]

On Sun, Nov 04, 2018 at 09:57:21PM -0600, Jeff LaBundy wrote:
> This patch adds binding documentation for the Azoteq IQS550/572/525
> family of trackpad/touchscreen controllers.
> 
> Signed-off-by: Jeff LaBundy <jeff@labundy.com>
> ---
>  .../bindings/input/touchscreen/iqs5xx.txt          | 123 +++++++++++++++++++++
>  .../devicetree/bindings/vendor-prefixes.txt        |   1 +
>  2 files changed, 124 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/iqs5xx.txt
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/iqs5xx.txt b/Documentation/devicetree/bindings/input/touchscreen/iqs5xx.txt
> new file mode 100644
> index 0000000..d201f68
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/touchscreen/iqs5xx.txt
> @@ -0,0 +1,123 @@
> +Azoteq IQS550/572/525 Trackpad/Touchscreen Controller
> +
> +Required properties:
> +
> +- compatible			: One of "azoteq,iqs550", "azoteq,iqs572" or
> +				  "azoteq,iqs525".

Format as 1 per line please.

> +
> +- reg				: I2C slave address for the device.
> +
> +- interrupts			: GPIO to which the device's RDY output is
> +				  connected (see [0] for more information).
> +
> +- reset-gpios			: GPIO to which the device's NRST input is
> +				  connected (see [1] for more information).
> +				  Hardware reset access is required so as to
> +				  facilitate in-system firmware replacement.

Active low?

> +
> +Optional properties:
> +
> +- azoteq,exp-ver-major		: Major field of the export file version number
> +				  (0 through 255 inclusive). This property must
> +				  be specified as a '/bits/ 8' value.
> +
> +- azoteq,exp-ver-minor		: Minor field of the export file version number
> +				  (0 through 255 inclusive). This property must
> +				  be specified as a '/bits/ 8' value.
> +
> +				  The export file version number is a customer-
> +				  assigned parameter embedded in the device's
> +				  firmware at the time it is exported from the
> +				  manufacturer's PC-based configuration tool.
> +
> +				  If the export file version number stored in
> +				  the device's nonvolatile memory does not match
> +				  the number specified here, the driver replaces
> +				  the firmware on the device with that which is
> +				  stored on the local filesystem (for which the
> +				  export file version number must match).
> +
> +				  If both major and minor fields are omitted or
> +				  specified as zero, the driver does not query
> +				  the device's export file version number.
> +
> +- touchscreen-min-x		: Minimum horizontal coordinate that can be
> +				  reported by the device. If this property is
> +				  omitted, zero is used.
> +
> +- touchscreen-min-y		: Minimum vertical coordinate that can be
> +				  reported by the device. If this property is
> +				  omitted, zero is used.
> +
> +- touchscreen-size-x		: Horizontal resolution (in pixels) of the touch
> +				  area. If this property is omitted, the default
> +				  horizontal resolution embedded in the device's
> +				  firmware is used.
> +
> +- touchscreen-size-y		: Vertical resolution (in pixels) of the touch
> +				  area. If this property is omitted, the default
> +				  vertical resolution embedded in the device's
> +				  firmware is used.
> +
> +- touchscreen-max-pressure	: Maximum touch strength that can be reported by
> +				  the device, specified as the sum of the deltas
> +				  across all channels impacted by a touch event.
> +				  A channel's delta is calculated as its count
> +				  value minus a reference, where the count value
> +				  is inversely proportional to the channel's
> +				  capacitance. The maximum touch strength is
> +				  therefore dependent on hardware configuration
> +				  and can vary by application.
> +
> +- touchscreen-fuzz-x		: Hysteresis level (in pixels) applied to the
> +				  horizontal coordinates reported by the device.
> +
> +- touchscreen-fuzz-y		: Hysteresis level (in pixels) applied to the
> +				  vertical coordinates reported by the device.
> +
> +- touchscreen-fuzz-pressure	: Hysteresis level applied to the strength level
> +				  reported by the device, specified in the same
> +				  units as touchscreen-max-pressure (deltas).
> +
> +- touchscreen-inverted-x	: Boolean to indicate that the horizontal axis
> +				  of the touch area is inverted. Inversion is
> +				  applied relative to that which may already be
> +				  embedded in the device's firmware.
> +
> +- touchscreen-inverted-y	: Boolean to indicate that the vertical axis
> +				  of the touch area is inverted. Inversion is
> +				  applied relative to that which may already be
> +				  embedded in the device's firmware.
> +
> +- touchscreen-swapped-x-y	: Boolean to indicate that the horizontal and
> +				  vertical axes of the touch area are swapped.
> +				  Transposition is applied relative to that
> +				  which may already be embedded in the device's
> +				  firmware.

No need to define all these standard properties again. Just reference 
touchscreen.txt. If you have any additional constraints, then add them 
here.

> +
> +[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
> +[1]: Documentation/devicetree/bindings/gpio/gpio.txt
> +
> +Example:
> +
> +	&i2c1 {
> +		/* ... */
> +
> +		iqs550: iqs550@74 {

touchscreen@74

> +			compatible = "azoteq,iqs550";
> +			reg = <0x74>;
> +			interrupt-parent = <&gpio>;
> +			interrupts = <17 1>;
> +			reset-gpios = <&gpio 27 0>;
> +
> +			azoteq,exp-ver-major = /bits/ 8 <1>;
> +			azoteq,exp-ver-minor = /bits/ 8 <0>;
> +
> +			touchscreen-size-x = <640>;
> +			touchscreen-size-y = <480>;
> +
> +			touchscreen-max-pressure = <16000>;
> +		};
> +
> +		/* ... */
> +	};
> diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
> index a38d8bf..d2ed740 100644
> --- a/Documentation/devicetree/bindings/vendor-prefixes.txt
> +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
> @@ -49,6 +49,7 @@ avia	avia semiconductor
>  avic	Shanghai AVIC Optoelectronics Co., Ltd.
>  axentia	Axentia Technologies AB
>  axis	Axis Communications AB
> +azoteq	Azoteq (Pty) Ltd
>  bananapi BIPAI KEJI LIMITED
>  bhf	Beckhoff Automation GmbH & Co. KG
>  boe	BOE Technology Group Co., Ltd.
> -- 
> 2.7.4
>