/* *  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/property.h>#include <linux/input.h>#include <linux/input/mt.h>#include <linux/input/touchscreen.h> static bool touchscreen_get_prop_u32(struct device *dev,				     const char *property,				     unsigned int default_value,				     unsigned int *value){	u32 val;	int error; 	error = device_property_read_u32(dev, 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)) {		dev_warn(&dev->dev,			 "DT specifies parameters but the axis %lu is not set up\n",			 axis);		return;	} 	absinfo = &dev->absinfo[axis];	absinfo->maximum = max;	absinfo->fuzz = fuzz;} /** * touchscreen_parse_properties - parse common touchscreen DT properties * @input: input device that should be parsed * @multitouch: specifies whether parsed properties should be applied to *	single-touch or multi-touch axes * * This function parses common DT properties for touchscreens and setups the * input device accordingly. The function keeps previously set up default * values if no value is specified via DT. */void touchscreen_parse_properties(struct input_dev *input, bool multitouch){	struct device *dev = input->dev.parent;	unsigned int axis;	unsigned int maximum, fuzz;	bool data_present; 	input_alloc_absinfo(input);	if (!input->absinfo)		return; 	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",						input_abs_get_max(input,								  axis) + 1,						&maximum) |		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",						input_abs_get_fuzz(input, axis),						&fuzz);	if (data_present)		touchscreen_set_params(input, axis, maximum - 1, fuzz); 	axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",						input_abs_get_max(input,								  axis) + 1,						&maximum) |		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",						input_abs_get_fuzz(input, axis),						&fuzz);	if (data_present)		touchscreen_set_params(input, axis, maximum - 1, fuzz); 	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;	data_present = touchscreen_get_prop_u32(dev,						"touchscreen-max-pressure",						input_abs_get_max(input, axis),						&maximum) |		       touchscreen_get_prop_u32(dev,						"touchscreen-fuzz-pressure",						input_abs_get_fuzz(input, axis),						&fuzz);	if (data_present)		touchscreen_set_params(input, axis, maximum, fuzz);}EXPORT_SYMBOL(touchscreen_parse_properties);