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