drivers/input/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/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
  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
  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  */
  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
 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  */
 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  */
 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");