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: Pavel Machek <pavel@ucw.cz>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Sebastian Reichel 2014-05-28 23:51:53 -07:00 committed by Dmitry Torokhov
parent 50525cb3bf
commit b98abe52fa
5 changed files with 99 additions and 0 deletions

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@ -0,0 +1,27 @@
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

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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

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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

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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);

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@ -0,0 +1,22 @@
/*
* 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