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
 14static 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
 32static 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 */
 64void 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, axis_x, axis_y;
 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_x = multitouch ? ABS_MT_POSITION_X : ABS_X;
 78	axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
 79
 80	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x",
 81						input_abs_get_min(input, axis_x),
 82						&minimum) |
 83		       touchscreen_get_prop_u32(dev, "touchscreen-size-x",
 84						input_abs_get_max(input,
 85								  axis_x) + 1,
 86						&maximum) |
 87		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
 88						input_abs_get_fuzz(input, axis_x),
 89						&fuzz);
 90	if (data_present)
 91		touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz);
 92
 93	data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y",
 94						input_abs_get_min(input, axis_y),
 95						&minimum) |
 96		       touchscreen_get_prop_u32(dev, "touchscreen-size-y",
 97						input_abs_get_max(input,
 98								  axis_y) + 1,
 99						&maximum) |
100		       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
101						input_abs_get_fuzz(input, axis_y),
102						&fuzz);
103	if (data_present)
104		touchscreen_set_params(input, axis_y, minimum, maximum - 1, fuzz);
105
106	axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
107	data_present = touchscreen_get_prop_u32(dev,
108						"touchscreen-max-pressure",
109						input_abs_get_max(input, axis),
110						&maximum) |
111		       touchscreen_get_prop_u32(dev,
112						"touchscreen-fuzz-pressure",
113						input_abs_get_fuzz(input, axis),
114						&fuzz);
115	if (data_present)
116		touchscreen_set_params(input, axis, 0, maximum, fuzz);
117
118	if (!prop)
119		return;
120
121	prop->max_x = input_abs_get_max(input, axis_x);
122	prop->max_y = input_abs_get_max(input, axis_y);
123
124	prop->invert_x =
125		device_property_read_bool(dev, "touchscreen-inverted-x");
126	if (prop->invert_x) {
127		absinfo = &input->absinfo[axis_x];
128		absinfo->maximum -= absinfo->minimum;
129		absinfo->minimum = 0;
130	}
131
132	prop->invert_y =
133		device_property_read_bool(dev, "touchscreen-inverted-y");
134	if (prop->invert_y) {
135		absinfo = &input->absinfo[axis_y];
136		absinfo->maximum -= absinfo->minimum;
137		absinfo->minimum = 0;
138	}
139
140	prop->swap_x_y =
141		device_property_read_bool(dev, "touchscreen-swapped-x-y");
142	if (prop->swap_x_y)
143		swap(input->absinfo[axis_x], input->absinfo[axis_y]);
144}
145EXPORT_SYMBOL(touchscreen_parse_properties);
146
147static void
148touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
149			      unsigned int *x, unsigned int *y)
150{
151	if (prop->invert_x)
152		*x = prop->max_x - *x;
153
154	if (prop->invert_y)
155		*y = prop->max_y - *y;
156
157	if (prop->swap_x_y)
158		swap(*x, *y);
159}
160
161/**
162 * touchscreen_set_mt_pos - Set input_mt_pos coordinates
163 * @pos: input_mt_pos to set coordinates of
164 * @prop: pointer to a struct touchscreen_properties
165 * @x: X coordinate to store in pos
166 * @y: Y coordinate to store in pos
167 *
168 * Adjust the passed in x and y values applying any axis inversion and
169 * swapping requested in the passed in touchscreen_properties and store
170 * the result in a struct input_mt_pos.
171 */
172void touchscreen_set_mt_pos(struct input_mt_pos *pos,
173			    const struct touchscreen_properties *prop,
174			    unsigned int x, unsigned int y)
175{
176	touchscreen_apply_prop_to_x_y(prop, &x, &y);
177	pos->x = x;
178	pos->y = y;
179}
180EXPORT_SYMBOL(touchscreen_set_mt_pos);
181
182/**
183 * touchscreen_report_pos - Report touchscreen coordinates
184 * @input: input_device to report coordinates for
185 * @prop: pointer to a struct touchscreen_properties
186 * @x: X coordinate to report
187 * @y: Y coordinate to report
188 * @multitouch: Report coordinates on single-touch or multi-touch axes
189 *
190 * Adjust the passed in x and y values applying any axis inversion and
191 * swapping requested in the passed in touchscreen_properties and then
192 * report the resulting coordinates on the input_dev's x and y axis.
193 */
194void touchscreen_report_pos(struct input_dev *input,
195			    const struct touchscreen_properties *prop,
196			    unsigned int x, unsigned int y,
197			    bool multitouch)
198{
199	touchscreen_apply_prop_to_x_y(prop, &x, &y);
200	input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
201	input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
202}
203EXPORT_SYMBOL(touchscreen_report_pos);
204
205MODULE_LICENSE("GPL v2");
206MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");