touchscreen.c

  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
 16static 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
 34static 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 */
 66void 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}
147EXPORT_SYMBOL(touchscreen_parse_properties);
148
149static void
150touchscreen_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 */
174void 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}
182EXPORT_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 */
196void 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}
205EXPORT_SYMBOL(touchscreen_report_pos);
206
207MODULE_LICENSE("GPL v2");
208MODULE_DESCRIPTION("Helper functions for touchscreens and other devices");