1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  Generic helper functions for touchscreens and other two-dimensional
4 *  pointing devices
5 *
6 *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
7 */
8
9#include <linux/property.h>
10#include <linux/input.h>
11#include <linux/input/mt.h>
12#include <linux/input/touchscreen.h>
13#include <linux/module.h>
14
15static bool touchscreen_get_prop_u32(struct device *dev,
16				     const char *property,
17				     unsigned int default_value,
18				     unsigned int *value)
19{
20	u32 val;
21	int error;
22
23	error = device_property_read_u32(dev, property, &val);
24	if (error) {
25		*value = default_value;
26		return false;
27	}
28
29	*value = val;
30	return true;
31}
32
33static void touchscreen_set_params(struct input_dev *dev,
34				   unsigned long axis,
35				   int min, int max, int fuzz)
36{
37	struct input_absinfo *absinfo;
38
39	if (!test_bit(axis, dev->absbit)) {
40		dev_warn(&dev->dev,
41			 "Parameters are specified but the axis %lu is not set up\n",
42			 axis);
43		return;
44	}
45
46	absinfo = &dev->absinfo[axis];
47	absinfo->minimum = min;
48	absinfo->maximum = max;
49	absinfo->fuzz = fuzz;
50}
51
52/**
53 * touchscreen_parse_properties - parse common touchscreen properties
54 * @input: input device that should be parsed
55 * @multitouch: specifies whether parsed properties should be applied to
56 *	single-touch or multi-touch axes
57 * @prop: pointer to a struct touchscreen_properties into which to store
58 *	axis swap and invert info for use with touchscreen_report_x_y();
59 *	or %NULL
60 *
61 * This function parses common properties for touchscreens and sets up the
62 * input device accordingly. The function keeps previously set up default
63 * values if no value is specified.
64 */
65void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
66				  struct touchscreen_properties *prop)
67{
68	struct device *dev = input->dev.parent;
69	struct input_absinfo *absinfo;
70	unsigned int axis, axis_x, axis_y;
71	unsigned int minimum, maximum, fuzz;
72	bool data_present;
73
74	input_alloc_absinfo(input);
75	if (!input->absinfo)
76		return;
77
78	axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
79	axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
80
81	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
82						input_abs_get_min(input, axis_x),
83						&minimum);
84	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
85						 input_abs_get_max(input,
86								   axis_x) + 1,
87						 &maximum);
88	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
89						 input_abs_get_fuzz(input, axis_x),
90						 &fuzz);
91	if (data_present)
92		touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
93
94	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
95						input_abs_get_min(input, axis_y),
96						&minimum);
97	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
98						 input_abs_get_max(input,
99								   axis_y) + 1,
100						 &maximum);
101	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
102						 input_abs_get_fuzz(input, axis_y),
103						 &fuzz);
104	if (data_present)
105		touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
106
107	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
108	data_present = touchscreen_get_prop_u32(dev,
109						"touchscreen-max-pressure",
110						input_abs_get_max(input, axis),
111						&maximum);
112	data_present |= touchscreen_get_prop_u32(dev,
113						 "touchscreen-fuzz-pressure",
114						 input_abs_get_fuzz(input, axis),
115						 &fuzz);
116	if (data_present)
117		touchscreen_set_params(input, axis, 0, maximum, fuzz);
118
119	if (!prop)
120		return;
121
122	prop->max_x = input_abs_get_max(input, axis_x);
123	prop->max_y = input_abs_get_max(input, axis_y);
124
125	prop->invert_x =
126		device_property_read_bool(dev, "touchscreen-inverted-x");
127	if (prop->invert_x) {
128		absinfo = &input->absinfo[axis_x];
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_y];
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_x], input->absinfo[axis_y]);
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("Helper functions for touchscreens and other devices");
208