1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  Generic DT helper functions for touchscreen devices
  4 *
  5 *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
  6 */
  7
  8#include <linux/property.h>
  9#include <linux/input.h>
 10#include <linux/input/mt.h>
 11#include <linux/input/touchscreen.h>
 12#include <linux/module.h>
 13
 14static bool touchscreen_get_prop_u32(struct device *dev,
 15				     const char *property,
 16				     unsigned int default_value,
 17				     unsigned int *value)
 18{
 19	u32 val;
 20	int error;
 21
 22	error = device_property_read_u32(dev, property, &val);
 23	if (error) {
 24		*value = default_value;
 25		return false;
 26	}
 27
 28	*value = val;
 29	return true;
 30}
 31
 32static void touchscreen_set_params(struct input_dev *dev,
 33				   unsigned long axis,
 34				   int min, int max, int fuzz)
 35{
 36	struct input_absinfo *absinfo;
 37
 38	if (!test_bit(axis, dev->absbit)) {
 39		dev_warn(&dev->dev,
 40			 "DT specifies parameters but the axis %lu is not set up\n",
 41			 axis);
 42		return;
 43	}
 44
 45	absinfo = &dev->absinfo[axis];
 46	absinfo->minimum = min;
 47	absinfo->maximum = max;
 48	absinfo->fuzz = fuzz;
 49}
 50
 51/**
 52 * touchscreen_parse_properties - parse common touchscreen DT properties
 53 * @input: input device that should be parsed
 54 * @multitouch: specifies whether parsed properties should be applied to
 55 *	single-touch or multi-touch axes
 56 * @prop: pointer to a struct touchscreen_properties into which to store
 57 *	axis swap and invert info for use with touchscreen_report_x_y();
 58 *	or %NULL
 59 *
 60 * This function parses common DT properties for touchscreens and setups the
 61 * input device accordingly. The function keeps previously set up default
 62 * values if no value is specified via DT.
 63 */
 64void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
 65				  struct touchscreen_properties *prop)
 66{
 67	struct device *dev = input->dev.parent;
 68	struct input_absinfo *absinfo;
 69	unsigned int axis;
 70	unsigned int minimum, maximum, fuzz;
 71	bool data_present;
 72
 73	input_alloc_absinfo(input);
 74	if (!input->absinfo)
 75		return;
 76
 77	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
 78	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
 79						input_abs_get_min(input, axis),
 80						&minimum) |
 81		       touchscreen_get_prop_u32(dev, "touchscreen-size-x",
 82						input_abs_get_max(input,
 83								  axis) + 1,
 84						&maximum) |
 85		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
 86						input_abs_get_fuzz(input, axis),
 87						&fuzz);
 88	if (data_present)
 89		touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
 90
 91	axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
 92	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
 93						input_abs_get_min(input, axis),
 94						&minimum) |
 95		       touchscreen_get_prop_u32(dev, "touchscreen-size-y",
 96						input_abs_get_max(input,
 97								  axis) + 1,
 98						&maximum) |
 99		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
100						input_abs_get_fuzz(input, axis),
101						&fuzz);
102	if (data_present)
103		touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
104
105	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
106	data_present = touchscreen_get_prop_u32(dev,
107						"touchscreen-max-pressure",
108						input_abs_get_max(input, axis),
109						&maximum) |
110		       touchscreen_get_prop_u32(dev,
111						"touchscreen-fuzz-pressure",
112						input_abs_get_fuzz(input, axis),
113						&fuzz);
114	if (data_present)
115		touchscreen_set_params(input, axis, 0, maximum, fuzz);
116
117	if (!prop)
118		return;
119
120	axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
121
122	prop->max_x = input_abs_get_max(input, axis);
123	prop->max_y = input_abs_get_max(input, axis + 1);
124
125	prop->invert_x =
126		device_property_read_bool(dev, "touchscreen-inverted-x");
127	if (prop->invert_x) {
128		absinfo = &input->absinfo[axis];
129		absinfo->maximum -= absinfo->minimum;
130		absinfo->minimum = 0;
131	}
132
133	prop->invert_y =
134		device_property_read_bool(dev, "touchscreen-inverted-y");
135	if (prop->invert_y) {
136		absinfo = &input->absinfo[axis + 1];
137		absinfo->maximum -= absinfo->minimum;
138		absinfo->minimum = 0;
139	}
140
141	prop->swap_x_y =
142		device_property_read_bool(dev, "touchscreen-swapped-x-y");
143	if (prop->swap_x_y)
144		swap(input->absinfo[axis], input->absinfo[axis + 1]);
145}
146EXPORT_SYMBOL(touchscreen_parse_properties);
147
148static void
149touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
150			      unsigned int *x, unsigned int *y)
151{
152	if (prop->invert_x)
153		*x = prop->max_x - *x;
154
155	if (prop->invert_y)
156		*y = prop->max_y - *y;
157
158	if (prop->swap_x_y)
159		swap(*x, *y);
160}
161
162/**
163 * touchscreen_set_mt_pos - Set input_mt_pos coordinates
164 * @pos: input_mt_pos to set coordinates of
165 * @prop: pointer to a struct touchscreen_properties
166 * @x: X coordinate to store in pos
167 * @y: Y coordinate to store in pos
168 *
169 * Adjust the passed in x and y values applying any axis inversion and
170 * swapping requested in the passed in touchscreen_properties and store
171 * the result in a struct input_mt_pos.
172 */
173void touchscreen_set_mt_pos(struct input_mt_pos *pos,
174			    const struct touchscreen_properties *prop,
175			    unsigned int x, unsigned int y)
176{
177	touchscreen_apply_prop_to_x_y(prop, &x, &y);
178	pos->x = x;
179	pos->y = y;
180}
181EXPORT_SYMBOL(touchscreen_set_mt_pos);
182
183/**
184 * touchscreen_report_pos - Report touchscreen coordinates
185 * @input: input_device to report coordinates for
186 * @prop: pointer to a struct touchscreen_properties
187 * @x: X coordinate to report
188 * @y: Y coordinate to report
189 * @multitouch: Report coordinates on single-touch or multi-touch axes
190 *
191 * Adjust the passed in x and y values applying any axis inversion and
192 * swapping requested in the passed in touchscreen_properties and then
193 * report the resulting coordinates on the input_dev's x and y axis.
194 */
195void touchscreen_report_pos(struct input_dev *input,
196			    const struct touchscreen_properties *prop,
197			    unsigned int x, unsigned int y,
198			    bool multitouch)
199{
200	touchscreen_apply_prop_to_x_y(prop, &x, &y);
201	input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
202	input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
203}
204EXPORT_SYMBOL(touchscreen_report_pos);
205
206MODULE_LICENSE("GPL v2");
207MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");