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 | |
15 | static 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 | |
33 | static 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 | */ |
65 | void 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 | } |
146 | EXPORT_SYMBOL(touchscreen_parse_properties); |
147 | |
148 | static void |
149 | touchscreen_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 | */ |
173 | void 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 | } |
181 | EXPORT_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 | */ |
195 | void 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 | } |
204 | EXPORT_SYMBOL(touchscreen_report_pos); |
205 | |
206 | MODULE_LICENSE("GPL v2" ); |
207 | MODULE_DESCRIPTION("Helper functions for touchscreens and other devices" ); |
208 | |