drivers/input/touchscreen/of_touchscreen.c

   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
  14 static 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
  32 static 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  */
  64 void 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 }
 145 EXPORT_SYMBOL(touchscreen_parse_properties);
 146
 147 static void
 148 touchscreen_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  */
 172 void 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 }
 180 EXPORT_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  */
 194 void 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 }
 203 EXPORT_SYMBOL(touchscreen_report_pos);
 204
 205 MODULE_LICENSE("GPL v2");
 206 MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");