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#include <linux/module.h>
 17
 18static bool touchscreen_get_prop_u32(struct device *dev,
 19				     const char *property,
 20				     unsigned int default_value,
 21				     unsigned int *value)
 22{
 23	u32 val;
 24	int error;
 25
 26	error = device_property_read_u32(dev, property, &val);
 27	if (error) {
 28		*value = default_value;
 29		return false;
 30	}
 31
 32	*value = val;
 33	return true;
 34}
 35
 36static void touchscreen_set_params(struct input_dev *dev,
 37				   unsigned long axis,
 38				   int max, int fuzz)
 39{
 40	struct input_absinfo *absinfo;
 41
 42	if (!test_bit(axis, dev->absbit)) {
 43		dev_warn(&dev->dev,
 44			 "DT specifies parameters but the axis %lu is not set up\n",
 45			 axis);
 46		return;
 47	}
 48
 49	absinfo = &dev->absinfo[axis];
 50	absinfo->maximum = max;
 51	absinfo->fuzz = fuzz;
 52}
 53
 54/**
 55 * touchscreen_parse_properties - parse common touchscreen DT properties
 56 * @input: input device that should be parsed
 57 * @multitouch: specifies whether parsed properties should be applied to
 58 *	single-touch or multi-touch axes
 59 * @prop: pointer to a struct touchscreen_properties into which to store
 60 *	axis swap and invert info for use with touchscreen_report_x_y();
 61 *	or %NULL
 62 *
 63 * This function parses common DT properties for touchscreens and setups the
 64 * input device accordingly. The function keeps previously set up default
 65 * values if no value is specified via DT.
 66 */
 67void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
 68				  struct touchscreen_properties *prop)
 69{
 70	struct device *dev = input->dev.parent;
 71	unsigned int axis;
 72	unsigned int maximum, fuzz;
 73	bool data_present;
 74
 75	input_alloc_absinfo(input);
 76	if (!input->absinfo)
 77		return;
 78
 79	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
 80	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
 81						input_abs_get_max(input,
 82								  axis) + 1,
 83						&maximum) |
 84		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
 85						input_abs_get_fuzz(input, axis),
 86						&fuzz);
 87	if (data_present)
 88		touchscreen_set_params(input, axis, maximum - 1, fuzz);
 89
 90	axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
 91	data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
 92						input_abs_get_max(input,
 93								  axis) + 1,
 94						&maximum) |
 95		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
 96						input_abs_get_fuzz(input, axis),
 97						&fuzz);
 98	if (data_present)
 99		touchscreen_set_params(input, axis, maximum - 1, fuzz);
100
101	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
102	data_present = touchscreen_get_prop_u32(dev,
103						"touchscreen-max-pressure",
104						input_abs_get_max(input, axis),
105						&maximum) |
106		       touchscreen_get_prop_u32(dev,
107						"touchscreen-fuzz-pressure",
108						input_abs_get_fuzz(input, axis),
109						&fuzz);
110	if (data_present)
111		touchscreen_set_params(input, axis, maximum, fuzz);
112
113	if (!prop)
114		return;
115
116	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
117
118	prop->max_x = input_abs_get_max(input, axis);
119	prop->max_y = input_abs_get_max(input, axis + 1);
120	prop->invert_x =
121		device_property_read_bool(dev, "touchscreen-inverted-x");
122	prop->invert_y =
123		device_property_read_bool(dev, "touchscreen-inverted-y");
124	prop->swap_x_y =
125		device_property_read_bool(dev, "touchscreen-swapped-x-y");
126
127	if (prop->swap_x_y)
128		swap(input->absinfo[axis], input->absinfo[axis + 1]);
129}
130EXPORT_SYMBOL(touchscreen_parse_properties);
131
132static void
133touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
134			      unsigned int *x, unsigned int *y)
135{
136	if (prop->invert_x)
137		*x = prop->max_x - *x;
138
139	if (prop->invert_y)
140		*y = prop->max_y - *y;
141
142	if (prop->swap_x_y)
143		swap(*x, *y);
144}
145
146/**
147 * touchscreen_set_mt_pos - Set input_mt_pos coordinates
148 * @pos: input_mt_pos to set coordinates of
149 * @prop: pointer to a struct touchscreen_properties
150 * @x: X coordinate to store in pos
151 * @y: Y coordinate to store in pos
152 *
153 * Adjust the passed in x and y values applying any axis inversion and
154 * swapping requested in the passed in touchscreen_properties and store
155 * the result in a struct input_mt_pos.
156 */
157void touchscreen_set_mt_pos(struct input_mt_pos *pos,
158			    const struct touchscreen_properties *prop,
159			    unsigned int x, unsigned int y)
160{
161	touchscreen_apply_prop_to_x_y(prop, &x, &y);
162	pos->x = x;
163	pos->y = y;
164}
165EXPORT_SYMBOL(touchscreen_set_mt_pos);
166
167/**
168 * touchscreen_report_pos - Report touchscreen coordinates
169 * @input: input_device to report coordinates for
170 * @prop: pointer to a struct touchscreen_properties
171 * @x: X coordinate to report
172 * @y: Y coordinate to report
173 * @multitouch: Report coordinates on single-touch or multi-touch axes
174 *
175 * Adjust the passed in x and y values applying any axis inversion and
176 * swapping requested in the passed in touchscreen_properties and then
177 * report the resulting coordinates on the input_dev's x and y axis.
178 */
179void touchscreen_report_pos(struct input_dev *input,
180			    const struct touchscreen_properties *prop,
181			    unsigned int x, unsigned int y,
182			    bool multitouch)
183{
184	touchscreen_apply_prop_to_x_y(prop, &x, &y);
185	input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
186	input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
187}
188EXPORT_SYMBOL(touchscreen_report_pos);
189
190MODULE_LICENSE("GPL v2");
191MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");