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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/mt.h>
#include <linux/input/touchscreen.h>
static u32 of_get_optional_u32(struct device_node *np,
const char *property)
{
u32 val = 0;
of_property_read_u32(np, property, &val);
return val;
}
static void touchscreen_set_params(struct input_dev *dev,
unsigned long axis,
int max, int fuzz)
{
struct input_absinfo *absinfo;
if (!test_bit(axis, dev->absbit)) {
/*
* Emit a warning only if the axis is not a multitouch
* axis, which might not be set by the driver.
*/
if (!input_is_mt_axis(axis))
dev_warn(&dev->dev,
"DT specifies parameters but the axis is not set up\n");
return;
}
absinfo = &dev->absinfo[axis];
absinfo->maximum = max;
absinfo->fuzz = fuzz;
}
/**
* 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;
u32 maximum, fuzz;
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
maximum = of_get_optional_u32(np, "touchscreen-size-x");
fuzz = of_get_optional_u32(np, "touchscreen-fuzz-x");
if (maximum || fuzz) {
touchscreen_set_params(dev, ABS_X, maximum, fuzz);
touchscreen_set_params(dev, ABS_MT_POSITION_X, maximum, fuzz);
}
maximum = of_get_optional_u32(np, "touchscreen-size-y");
fuzz = of_get_optional_u32(np, "touchscreen-fuzz-y");
if (maximum || fuzz) {
touchscreen_set_params(dev, ABS_Y, maximum, fuzz);
touchscreen_set_params(dev, ABS_MT_POSITION_Y, maximum, fuzz);
}
maximum = of_get_optional_u32(np, "touchscreen-max-pressure");
fuzz = of_get_optional_u32(np, "touchscreen-fuzz-pressure");
if (maximum || fuzz) {
touchscreen_set_params(dev, ABS_PRESSURE, maximum, fuzz);
touchscreen_set_params(dev, ABS_MT_PRESSURE, maximum, fuzz);
}
}
EXPORT_SYMBOL(touchscreen_parse_of_params);
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