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
touchscreen_get_prop_u32(struct device * dev,const char * property,unsigned int default_value,unsigned int * value)14 static 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
touchscreen_set_params(struct input_dev * dev,unsigned long axis,int min,int max,int fuzz)32 static 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 */
touchscreen_parse_properties(struct input_dev * input,bool multitouch,struct touchscreen_properties * prop)64 void 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;
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 = multitouch ? ABS_MT_POSITION_X : ABS_X;
78 data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
79 input_abs_get_min(input, axis),
80 &minimum);
81 data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
82 input_abs_get_max(input,
83 axis) + 1,
84 &maximum);
85 data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
86 input_abs_get_fuzz(input, axis),
87 &fuzz);
88 if (data_present)
89 touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
90
91 axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
92 data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
93 input_abs_get_min(input, axis),
94 &minimum);
95 data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
96 input_abs_get_max(input,
97 axis) + 1,
98 &maximum);
99 data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
100 input_abs_get_fuzz(input, axis),
101 &fuzz);
102 if (data_present)
103 touchscreen_set_params(input, axis, minimum, maximum - 1, fuzz);
104
105 axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
106 data_present = touchscreen_get_prop_u32(dev,
107 "touchscreen-max-pressure",
108 input_abs_get_max(input, axis),
109 &maximum);
110 data_present |= touchscreen_get_prop_u32(dev,
111 "touchscreen-fuzz-pressure",
112 input_abs_get_fuzz(input, axis),
113 &fuzz);
114 if (data_present)
115 touchscreen_set_params(input, axis, 0, maximum, fuzz);
116
117 if (!prop)
118 return;
119
120 axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
121
122 prop->max_x = input_abs_get_max(input, axis);
123 prop->max_y = input_abs_get_max(input, axis + 1);
124
125 prop->invert_x =
126 device_property_read_bool(dev, "touchscreen-inverted-x");
127 if (prop->invert_x) {
128 absinfo = &input->absinfo[axis];
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 + 1];
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], input->absinfo[axis + 1]);
145 }
146 EXPORT_SYMBOL(touchscreen_parse_properties);
147
148 static void
touchscreen_apply_prop_to_x_y(const struct touchscreen_properties * prop,unsigned int * x,unsigned int * y)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 */
touchscreen_set_mt_pos(struct input_mt_pos * pos,const struct touchscreen_properties * prop,unsigned int x,unsigned int y)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, &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 */
touchscreen_report_pos(struct input_dev * input,const struct touchscreen_properties * prop,unsigned int x,unsigned int y,bool multitouch)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, &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 }
204 EXPORT_SYMBOL(touchscreen_report_pos);
205
206 MODULE_LICENSE("GPL v2");
207 MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");
208