/* *  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);