1/*
  2 *  Generic DT helper functions for touchscreen devices
  3 *
  4 *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
  5 *
  6 *  This program is free software; you can redistribute it and/or modify
  7 *  it under the terms of the GNU General Public License version 2 as
  8 *  published by the Free Software Foundation.
  9 *
 10 */
 11
 12#include <linux/property.h>
 13#include <linux/input.h>
 14#include <linux/input/mt.h>
 15#include <linux/input/touchscreen.h>
 16
 17static bool touchscreen_get_prop_u32(struct device *dev,
 18				     const char *property,
 19				     unsigned int default_value,
 20				     unsigned int *value)
 21{
 22	u32 val;
 23	int error;
 24
 25	error = device_property_read_u32(dev, property, &val);
 26	if (error) {
 27		*value = default_value;
 28		return false;
 29	}
 30
 31	*value = val;
 32	return true;
 33}
 34
 35static void touchscreen_set_params(struct input_dev *dev,
 36				   unsigned long axis,
 37				   int max, int fuzz)
 38{
 39	struct input_absinfo *absinfo;
 40
 41	if (!test_bit(axis, dev->absbit)) {
 42		dev_warn(&dev->dev,
 43			 "DT specifies parameters but the axis %lu is not set up\n",
 44			 axis);
 45		return;
 46	}
 47
 48	absinfo = &dev->absinfo[axis];
 49	absinfo->maximum = max;
 50	absinfo->fuzz = fuzz;
 51}
 52
 53/**
 54 * touchscreen_parse_properties - parse common touchscreen DT properties
 55 * @input: input device that should be parsed
 56 * @multitouch: specifies whether parsed properties should be applied to
 57 *	single-touch or multi-touch axes
 58 *
 59 * This function parses common DT properties for touchscreens and setups the
 60 * input device accordingly. The function keeps previously set up default
 61 * values if no value is specified via DT.
 62 */
 63void touchscreen_parse_properties(struct input_dev *input, bool multitouch)
 64{
 65	struct device *dev = input->dev.parent;
 66	unsigned int axis;
 67	unsigned int maximum, fuzz;
 68	bool data_present;
 69
 70	input_alloc_absinfo(input);
 71	if (!input->absinfo)
 72		return;
 73
 74	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
 75	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
 76						input_abs_get_max(input,
 77								  axis) + 1,
 78						&maximum) |
 79		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
 80						input_abs_get_fuzz(input, axis),
 81						&fuzz);
 82	if (data_present)
 83		touchscreen_set_params(input, axis, maximum - 1, fuzz);
 84
 85	axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
 86	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
 87						input_abs_get_max(input,
 88								  axis) + 1,
 89						&maximum) |
 90		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
 91						input_abs_get_fuzz(input, axis),
 92						&fuzz);
 93	if (data_present)
 94		touchscreen_set_params(input, axis, maximum - 1, fuzz);
 95
 96	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
 97	data_present = touchscreen_get_prop_u32(dev,
 98						"touchscreen-max-pressure",
 99						input_abs_get_max(input, axis),
100						&maximum) |
101		       touchscreen_get_prop_u32(dev,
102						"touchscreen-fuzz-pressure",
103						input_abs_get_fuzz(input, axis),
104						&fuzz);
105	if (data_present)
106		touchscreen_set_params(input, axis, maximum, fuzz);
107}
108EXPORT_SYMBOL(touchscreen_parse_properties);