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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 bool touchscreen_get_prop_u32(struct device_node *np,
const char *property,
unsigned int default_value,
unsigned int *value)
{
u32 val;
int error;
error = of_property_read_u32(np, property, &val);
if (error) {
*value = default_value;
return false;
}
*value = val;
return true;
}
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, bool multitouch)
{
struct device_node *np = dev->dev.parent->of_node;
unsigned int axis;
unsigned int maximum, fuzz;
bool data_present;
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
data_present = touchscreen_get_prop_u32(np, "touchscreen-size-x",
input_abs_get_max(dev, axis),
&maximum) |
touchscreen_get_prop_u32(np, "touchscreen-fuzz-x",
input_abs_get_fuzz(dev, axis),
&fuzz);
if (data_present)
touchscreen_set_params(dev, axis, maximum, fuzz);
axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
data_present = touchscreen_get_prop_u32(np, "touchscreen-size-y",
input_abs_get_max(dev, axis),
&maximum) |
touchscreen_get_prop_u32(np, "touchscreen-fuzz-y",
input_abs_get_fuzz(dev, axis),
&fuzz);
if (data_present)
touchscreen_set_params(dev, axis, maximum, fuzz);
axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
data_present = touchscreen_get_prop_u32(np, "touchscreen-max-pressure",
input_abs_get_max(dev, axis),
&maximum) |
touchscreen_get_prop_u32(np, "touchscreen-fuzz-pressure",
input_abs_get_fuzz(dev, axis),
&fuzz);
if (data_present)
touchscreen_set_params(dev, axis, maximum, fuzz);
}
EXPORT_SYMBOL(touchscreen_parse_of_params);
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