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