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 
touchscreen_get_prop_u32(struct device * dev,const char * property,unsigned int default_value,unsigned int * value)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, property, &val);
24 	if (error) {
25 		*value = default_value;
26 		return false;
27 	}
28 
29 	*value = val;
30 	return true;
31 }
32 
touchscreen_set_params(struct input_dev * dev,unsigned long axis,int min,int max,int fuzz)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  */
touchscreen_parse_properties(struct input_dev * input,bool multitouch,struct touchscreen_properties * prop)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(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, "touchscreen-min-x",
82 						input_abs_get_min(input, axis_x),
83 						&minimum);
84 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x",
85 						 input_abs_get_max(input,
86 								   axis_x) + 1,
87 						 &maximum);
88 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
89 						 input_abs_get_fuzz(input, axis_x),
90 						 &fuzz);
91 	if (data_present)
92 		touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
93 
94 	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
95 						input_abs_get_min(input, axis_y),
96 						&minimum);
97 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y",
98 						 input_abs_get_max(input,
99 								   axis_y) + 1,
100 						 &maximum);
101 	data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
102 						 input_abs_get_fuzz(input, axis_y),
103 						 &fuzz);
104 	if (data_present)
105 		touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
106 
107 	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
108 	data_present = touchscreen_get_prop_u32(dev,
109 						"touchscreen-max-pressure",
110 						input_abs_get_max(input, axis),
111 						&maximum);
112 	data_present |= touchscreen_get_prop_u32(dev,
113 						 "touchscreen-fuzz-pressure",
114 						 input_abs_get_fuzz(input, axis),
115 						 &fuzz);
116 	if (data_present)
117 		touchscreen_set_params(input, axis, 0, maximum, fuzz);
118 
119 	if (!prop)
120 		return;
121 
122 	prop->max_x = input_abs_get_max(input, axis_x);
123 	prop->max_y = input_abs_get_max(input, axis_y);
124 
125 	prop->invert_x =
126 		device_property_read_bool(dev, "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, "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, "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
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("Helper functions for touchscreens and other devices");
208