Commit b98abe52 authored by Sebastian Reichel's avatar Sebastian Reichel Committed by Dmitry Torokhov
Browse files

Input: add common DT binding for touchscreens 



Add common DT binding documentation for touchscreen devices and
implement input_parse_touchscreen_of_params, which parses the common
properties and configures the input device accordingly.

The method currently does not interpret the axis inversion properties,
since there is no matching flag in the generic linux input device.

Reviewed-by: default avatarPavel Machek <pavel@ucw.cz>
Acked-by: default avatarAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 50525cb3

Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

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General Touchscreen Properties:



Optional properties for Touchscreens:

 - touchscreen-size-x		: horizontal resolution of touchscreen

				  (in pixels)

 - touchscreen-size-y		: vertical resolution of touchscreen

				  (in pixels)

 - touchscreen-max-pressure	: maximum reported pressure (arbitrary range

				  dependent on the controller)

 - touchscreen-fuzz-x		: horizontal noise value of the absolute input

				  device (in pixels)

 - touchscreen-fuzz-y		: vertical noise value of the absolute input

				  device (in pixels)

 - touchscreen-fuzz-pressure	: pressure noise value of the absolute input

				  device (arbitrary range dependent on the

				  controller)

 - touchscreen-inverted-x	: X axis is inverted (boolean)

 - touchscreen-inverted-y	: Y axis is inverted (boolean)



Deprecated properties for Touchscreens:

 - x-size			: deprecated name for touchscreen-size-x

 - y-size			: deprecated name for touchscreen-size-y

 - moving-threshold		: deprecated name for a combination of

				  touchscreen-fuzz-x and touchscreen-fuzz-y

 - contact-threshold		: deprecated name for touchscreen-fuzz-pressure

 - x-invert			: deprecated name for touchscreen-inverted-x

 - y-invert			: deprecated name for touchscreen-inverted-y

drivers/input/touchscreen/Kconfig

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@@ -11,6 +11,10 @@ menuconfig INPUT_TOUCHSCREEN 


if INPUT_TOUCHSCREEN



config OF_TOUCHSCREEN

	def_tristate INPUT

	depends on INPUT && OF



config TOUCHSCREEN_88PM860X

	tristate "Marvell 88PM860x touchscreen"

	depends on MFD_88PM860X

drivers/input/touchscreen/Makefile

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@@ -6,6 +6,7 @@ 


wm97xx-ts-y := wm97xx-core.o



obj-$(CONFIG_OF_TOUCHSCREEN)		+= of_touchscreen.o

obj-$(CONFIG_TOUCHSCREEN_88PM860X)	+= 88pm860x-ts.o

obj-$(CONFIG_TOUCHSCREEN_AD7877)	+= ad7877.o

obj-$(CONFIG_TOUCHSCREEN_AD7879)	+= ad7879.o

drivers/input/touchscreen/of_touchscreen.c

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/*

 *  Generic DT helper functions for touchscreen devices

 *

 *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License version 2 as

 *  published by the Free Software Foundation.

 *

 */



#include <linux/of.h>

#include <linux/input.h>

#include <linux/input/touchscreen.h>



/**

 * touchscreen_parse_of_params - parse common touchscreen DT properties

 * @dev: device that should be parsed

 *

 * This function parses common DT properties for touchscreens and setups the

 * input device accordingly. The function keeps previously setuped default

 * values if no value is specified via DT.

 */

void touchscreen_parse_of_params(struct input_dev *dev)

{

	struct device_node *np = dev->dev.parent->of_node;

	struct input_absinfo *absinfo;



	input_alloc_absinfo(dev);

	if (!dev->absinfo)

		return;



	absinfo = &dev->absinfo[ABS_X];

	of_property_read_u32(np, "touchscreen-size-x", &absinfo->maximum);

	of_property_read_u32(np, "touchscreen-fuzz-x", &absinfo->fuzz);



	absinfo = &dev->absinfo[ABS_Y];

	of_property_read_u32(np, "touchscreen-size-y", &absinfo->maximum);

	of_property_read_u32(np, "touchscreen-fuzz-y", &absinfo->fuzz);



	absinfo = &dev->absinfo[ABS_PRESSURE];

	of_property_read_u32(np, "touchscreen-max-pressure", &absinfo->maximum);

	of_property_read_u32(np, "touchscreen-fuzz-pressure", &absinfo->fuzz);

}

EXPORT_SYMBOL(touchscreen_parse_of_params);

include/linux/input/touchscreen.h

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/*

 * Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published by

 * the Free Software Foundation.

 */



#ifndef _TOUCHSCREEN_H

#define _TOUCHSCREEN_H



#include <linux/input.h>



#ifdef CONFIG_OF

void touchscreen_parse_of_params(struct input_dev *dev);

#else

static inline void touchscreen_parse_of_params(struct input_dev *dev)

{

}

#endif



#endif

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