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, axis_x, axis_y;
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_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
78	axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
79
80	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
81						input_abs_get_min(input, axis_x),
82						&minimum);
83	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
84						 input_abs_get_max(input,
85								   axis_x) + 1,
86						 &maximum);
87	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
88						 input_abs_get_fuzz(input, axis_x),
89						 &fuzz);
90	if (data_present)
91		touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
92
93	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
94						input_abs_get_min(input, axis_y),
95						&minimum);
96	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
97						 input_abs_get_max(input,
98								   axis_y) + 1,
99						 &maximum);
100	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
101						 input_abs_get_fuzz(input, axis_y),
102						 &fuzz);
103	if (data_present)
104		touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
105
106	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
107	data_present = touchscreen_get_prop_u32(dev,
108						"touchscreen-max-pressure",
109						input_abs_get_max(input, axis),
110						&maximum);
111	data_present |= touchscreen_get_prop_u32(dev,
112						 "touchscreen-fuzz-pressure",
113						 input_abs_get_fuzz(input, axis),
114						 &fuzz);
115	if (data_present)
116		touchscreen_set_params(input, axis, 0, maximum, fuzz);
117
118	if (!prop)
119		return;
120
121	prop->max_x = input_abs_get_max(input, axis_x);
122	prop->max_y = input_abs_get_max(input, axis_y);
123
124	prop->invert_x =
125		device_property_read_bool(dev, "touchscreen-inverted-x");
126	if (prop->invert_x) {
127		absinfo = &input->absinfo[axis_x];
128		absinfo->maximum -= absinfo->minimum;
129		absinfo->minimum = 0;
130	}
131
132	prop->invert_y =
133		device_property_read_bool(dev, "touchscreen-inverted-y");
134	if (prop->invert_y) {
135		absinfo = &input->absinfo[axis_y];
136		absinfo->maximum -= absinfo->minimum;
137		absinfo->minimum = 0;
138	}
139
140	prop->swap_x_y =
141		device_property_read_bool(dev, "touchscreen-swapped-x-y");
142	if (prop->swap_x_y)
143		swap(input->absinfo[axis_x], input->absinfo[axis_y]);
144}
145EXPORT_SYMBOL(touchscreen_parse_properties);
146
147static void
148touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
149			      unsigned int *x, unsigned int *y)
150{
151	if (prop->invert_x)
152		*x = prop->max_x - *x;
153
154	if (prop->invert_y)
155		*y = prop->max_y - *y;
156
157	if (prop->swap_x_y)
158		swap(*x, *y);
159}
160
161/**
162 * touchscreen_set_mt_pos - Set input_mt_pos coordinates
163 * @pos: input_mt_pos to set coordinates of
164 * @prop: pointer to a struct touchscreen_properties
165 * @x: X coordinate to store in pos
166 * @y: Y coordinate to store in pos
167 *
168 * Adjust the passed in x and y values applying any axis inversion and
169 * swapping requested in the passed in touchscreen_properties and store
170 * the result in a struct input_mt_pos.
171 */
172void touchscreen_set_mt_pos(struct input_mt_pos *pos,
173			    const struct touchscreen_properties *prop,
174			    unsigned int x, unsigned int y)
175{
176	touchscreen_apply_prop_to_x_y(prop, &x, &y);
177	pos->x = x;
178	pos->y = y;
179}
180EXPORT_SYMBOL(touchscreen_set_mt_pos);
181
182/**
183 * touchscreen_report_pos - Report touchscreen coordinates
184 * @input: input_device to report coordinates for
185 * @prop: pointer to a struct touchscreen_properties
186 * @x: X coordinate to report
187 * @y: Y coordinate to report
188 * @multitouch: Report coordinates on single-touch or multi-touch axes
189 *
190 * Adjust the passed in x and y values applying any axis inversion and
191 * swapping requested in the passed in touchscreen_properties and then
192 * report the resulting coordinates on the input_dev's x and y axis.
193 */
194void touchscreen_report_pos(struct input_dev *input,
195			    const struct touchscreen_properties *prop,
196			    unsigned int x, unsigned int y,
197			    bool multitouch)
198{
199	touchscreen_apply_prop_to_x_y(prop, &x, &y);
200	input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
201	input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
202}
203EXPORT_SYMBOL(touchscreen_report_pos);
204
205MODULE_LICENSE("GPL v2");
206MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");
207