xref: /linux/drivers/input/touchscreen.c (revision 68a052239fc4b351e961f698b824f7654a346091)
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/export.h>
10 #include <linux/property.h>
11 #include <linux/input.h>
12 #include <linux/input/mt.h>
13 #include <linux/input/touchscreen.h>
14 #include <linux/module.h>
15 
16 static bool touchscreen_get_prop_u32(struct device *dev,
17 				     const char *property,
18 				     unsigned int default_value,
19 				     unsigned int *value)
20 {
21 	u32 val;
22 	int error;
23 
24 	error = device_property_read_u32(dev, property, &val);
25 	if (error) {
26 		*value = default_value;
27 		return false;
28 	}
29 
30 	*value = val;
31 	return true;
32 }
33 
34 static void touchscreen_set_params(struct input_dev *dev,
35 				   unsigned long axis,
36 				   int min, int max, int fuzz)
37 {
38 	struct input_absinfo *absinfo;
39 
40 	if (!test_bit(axis, dev->absbit)) {
41 		dev_warn(&dev->dev,
42 			 "Parameters are specified but the axis %lu is not set up\n",
43 			 axis);
44 		return;
45 	}
46 
47 	absinfo = &dev->absinfo[axis];
48 	absinfo->minimum = min;
49 	absinfo->maximum = max;
50 	absinfo->fuzz = fuzz;
51 }
52 
53 /**
54  * touchscreen_parse_properties - parse common touchscreen 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 properties for touchscreens and sets up the
63  * input device accordingly. The function keeps previously set up default
64  * values if no value is specified.
65  */
66 void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
67 				  struct touchscreen_properties *prop)
68 {
69 	struct device *dev = input->dev.parent;
70 	struct input_absinfo *absinfo;
71 	unsigned int axis, axis_x, axis_y;
72 	unsigned int minimum, maximum, fuzz;
73 	bool data_present;
74 
75 	input_alloc_absinfo(input);
76 	if (!input->absinfo)
77 		return;
78 
79 	axis_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
80 	axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
81 
82 	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
83 						input_abs_get_min(input, axis_x),
84 						&minimum);
85 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
86 						 input_abs_get_max(input,
87 								   axis_x) + 1,
88 						 &maximum);
89 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
90 						 input_abs_get_fuzz(input, axis_x),
91 						 &fuzz);
92 	if (data_present)
93 		touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
94 
95 	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
96 						input_abs_get_min(input, axis_y),
97 						&minimum);
98 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
99 						 input_abs_get_max(input,
100 								   axis_y) + 1,
101 						 &maximum);
102 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
103 						 input_abs_get_fuzz(input, axis_y),
104 						 &fuzz);
105 	if (data_present)
106 		touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
107 
108 	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
109 	data_present = touchscreen_get_prop_u32(dev,
110 						"touchscreen-max-pressure",
111 						input_abs_get_max(input, axis),
112 						&maximum);
113 	data_present |= touchscreen_get_prop_u32(dev,
114 						 "touchscreen-fuzz-pressure",
115 						 input_abs_get_fuzz(input, axis),
116 						 &fuzz);
117 	if (data_present)
118 		touchscreen_set_params(input, axis, 0, maximum, fuzz);
119 
120 	if (!prop)
121 		return;
122 
123 	prop->max_x = input_abs_get_max(input, axis_x);
124 	prop->max_y = input_abs_get_max(input, axis_y);
125 
126 	prop->invert_x =
127 		device_property_read_bool(dev, "touchscreen-inverted-x");
128 	if (prop->invert_x) {
129 		absinfo = &input->absinfo[axis_x];
130 		absinfo->maximum -= absinfo->minimum;
131 		absinfo->minimum = 0;
132 	}
133 
134 	prop->invert_y =
135 		device_property_read_bool(dev, "touchscreen-inverted-y");
136 	if (prop->invert_y) {
137 		absinfo = &input->absinfo[axis_y];
138 		absinfo->maximum -= absinfo->minimum;
139 		absinfo->minimum = 0;
140 	}
141 
142 	prop->swap_x_y =
143 		device_property_read_bool(dev, "touchscreen-swapped-x-y");
144 	if (prop->swap_x_y)
145 		swap(input->absinfo[axis_x], input->absinfo[axis_y]);
146 }
147 EXPORT_SYMBOL(touchscreen_parse_properties);
148 
149 static void
150 touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
151 			      unsigned int *x, unsigned int *y)
152 {
153 	if (prop->invert_x)
154 		*x = prop->max_x - *x;
155 
156 	if (prop->invert_y)
157 		*y = prop->max_y - *y;
158 
159 	if (prop->swap_x_y)
160 		swap(*x, *y);
161 }
162 
163 /**
164  * touchscreen_set_mt_pos - Set input_mt_pos coordinates
165  * @pos: input_mt_pos to set coordinates of
166  * @prop: pointer to a struct touchscreen_properties
167  * @x: X coordinate to store in pos
168  * @y: Y coordinate to store in pos
169  *
170  * Adjust the passed in x and y values applying any axis inversion and
171  * swapping requested in the passed in touchscreen_properties and store
172  * the result in a struct input_mt_pos.
173  */
174 void touchscreen_set_mt_pos(struct input_mt_pos *pos,
175 			    const struct touchscreen_properties *prop,
176 			    unsigned int x, unsigned int y)
177 {
178 	touchscreen_apply_prop_to_x_y(prop, &x, &y);
179 	pos->x = x;
180 	pos->y = y;
181 }
182 EXPORT_SYMBOL(touchscreen_set_mt_pos);
183 
184 /**
185  * touchscreen_report_pos - Report touchscreen coordinates
186  * @input: input_device to report coordinates for
187  * @prop: pointer to a struct touchscreen_properties
188  * @x: X coordinate to report
189  * @y: Y coordinate to report
190  * @multitouch: Report coordinates on single-touch or multi-touch axes
191  *
192  * Adjust the passed in x and y values applying any axis inversion and
193  * swapping requested in the passed in touchscreen_properties and then
194  * report the resulting coordinates on the input_dev's x and y axis.
195  */
196 void touchscreen_report_pos(struct input_dev *input,
197 			    const struct touchscreen_properties *prop,
198 			    unsigned int x, unsigned int y,
199 			    bool multitouch)
200 {
201 	touchscreen_apply_prop_to_x_y(prop, &x, &y);
202 	input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
203 	input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
204 }
205 EXPORT_SYMBOL(touchscreen_report_pos);
206 
207 MODULE_LICENSE("GPL v2");
208 MODULE_DESCRIPTION("Helper functions for touchscreens and other devices");
209