LXR linux/drivers/input/touchscreen/of

   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");
 207