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, propname: property, val: &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(dev: 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, property: "touchscreen-min-x",
82 default_value: input_abs_get_min(dev: input, axis: axis_x),
83 value: &minimum);
84 data_present |= touchscreen_get_prop_u32(dev, property: "touchscreen-size-x",
85 default_value: input_abs_get_max(dev: input,
86 axis: axis_x) + 1,
87 value: &maximum);
88 data_present |= touchscreen_get_prop_u32(dev, property: "touchscreen-fuzz-x",
89 default_value: input_abs_get_fuzz(dev: input, axis: axis_x),
90 value: &fuzz);
91 if (data_present)
92 touchscreen_set_params(dev: input, axis: axis_x, min: minimum, max: maximum - 1, fuzz);
93
94 data_present = touchscreen_get_prop_u32(dev, property: "touchscreen-min-y",
95 default_value: input_abs_get_min(dev: input, axis: axis_y),
96 value: &minimum);
97 data_present |= touchscreen_get_prop_u32(dev, property: "touchscreen-size-y",
98 default_value: input_abs_get_max(dev: input,
99 axis: axis_y) + 1,
100 value: &maximum);
101 data_present |= touchscreen_get_prop_u32(dev, property: "touchscreen-fuzz-y",
102 default_value: input_abs_get_fuzz(dev: input, axis: axis_y),
103 value: &fuzz);
104 if (data_present)
105 touchscreen_set_params(dev: input, axis: axis_y, min: minimum, max: maximum - 1, fuzz);
106
107 axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
108 data_present = touchscreen_get_prop_u32(dev,
109 property: "touchscreen-max-pressure",
110 default_value: input_abs_get_max(dev: input, axis),
111 value: &maximum);
112 data_present |= touchscreen_get_prop_u32(dev,
113 property: "touchscreen-fuzz-pressure",
114 default_value: input_abs_get_fuzz(dev: input, axis),
115 value: &fuzz);
116 if (data_present)
117 touchscreen_set_params(dev: input, axis, min: 0, max: maximum, fuzz);
118
119 if (!prop)
120 return;
121
122 prop->max_x = input_abs_get_max(dev: input, axis: axis_x);
123 prop->max_y = input_abs_get_max(dev: input, axis: axis_y);
124
125 prop->invert_x =
126 device_property_read_bool(dev, propname: "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, propname: "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, propname: "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: &x, y: &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: &x, y: &y);
201 input_report_abs(dev: input, code: multitouch ? ABS_MT_POSITION_X : ABS_X, value: x);
202 input_report_abs(dev: input, code: multitouch ? ABS_MT_POSITION_Y : ABS_Y, value: y);
203}
204EXPORT_SYMBOL(touchscreen_report_pos);
205
206MODULE_LICENSE("GPL v2");
207MODULE_DESCRIPTION("Helper functions for touchscreens and other devices");
208

source code of linux/drivers/input/touchscreen.c

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