drivers/input/touchscreen/of_touchscreen.c

   1 /*
   2  *  Generic DT helper functions for touchscreen devices
   3  *
   4  *  Copyright (c) 2014 Sebastian Reichel <sre@kernel.org>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License version 2 as
   8  *  published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/property.h>
  13 #include <linux/input.h>
  14 #include <linux/input/mt.h>
  15 #include <linux/input/touchscreen.h>
  16
  17 static bool touchscreen_get_prop_u32(struct device *dev,
  18                                      const char *property,
  19                                      unsigned int default_value,
  20                                      unsigned int *value)
  21 {
  22         u32 val;
  23         int error;
  24
  25         error = device_property_read_u32(dev, property, &val);
  26         if (error) {
  27                 *value = default_value;
  28                 return false;
  29         }
  30
  31         *value = val;
  32         return true;
  33 }
  34
  35 static void touchscreen_set_params(struct input_dev *dev,
  36                                    unsigned long axis,
  37                                    int max, int fuzz)
  38 {
  39         struct input_absinfo *absinfo;
  40
  41         if (!test_bit(axis, dev->absbit)) {
  42                 dev_warn(&dev->dev,
  43                          "DT specifies parameters but the axis %lu is not set up\n",
  44                          axis);
  45                 return;
  46         }
  47
  48         absinfo = &dev->absinfo[axis];
  49         absinfo->maximum = max;
  50         absinfo->fuzz = fuzz;
  51 }
  52
  53 /**
  54  * touchscreen_parse_properties - parse common touchscreen DT properties
  55  * @input: input device that should be parsed
  56  * @multitouch: specifies whether parsed properties should be applied to
  57  *      single-touch or multi-touch axes
  58  * @prop: pointer to a struct touchscreen_properties into which to store
  59  *      axis swap and invert info for use with touchscreen_report_x_y();
  60  *      or %NULL
  61  *
  62  * This function parses common DT properties for touchscreens and setups the
  63  * input device accordingly. The function keeps previously set up default
  64  * values if no value is specified via DT.
  65  */
  66 void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
  67                                   struct touchscreen_properties *prop)
  68 {
  69         struct device *dev = input->dev.parent;
  70         unsigned int axis;
  71         unsigned int maximum, fuzz;
  72         bool data_present;
  73
  74         input_alloc_absinfo(input);
  75         if (!input->absinfo)
  76                 return;
  77
  78         axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
  79         data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
  80                                                 input_abs_get_max(input,
  81                                                                   axis) + 1,
  82                                                 &maximum) |
  83                        touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
  84                                                 input_abs_get_fuzz(input, axis),
  85                                                 &fuzz);
  86         if (data_present)
  87                 touchscreen_set_params(input, axis, maximum - 1, fuzz);
  88
  89         axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
  90         data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
  91                                                 input_abs_get_max(input,
  92                                                                   axis) + 1,
  93                                                 &maximum) |
  94                        touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
  95                                                 input_abs_get_fuzz(input, axis),
  96                                                 &fuzz);
  97         if (data_present)
  98                 touchscreen_set_params(input, axis, maximum - 1, fuzz);
  99
 100         axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
 101         data_present = touchscreen_get_prop_u32(dev,
 102                                                 "touchscreen-max-pressure",
 103                                                 input_abs_get_max(input, axis),
 104                                                 &maximum) |
 105                        touchscreen_get_prop_u32(dev,
 106                                                 "touchscreen-fuzz-pressure",
 107                                                 input_abs_get_fuzz(input, axis),
 108                                                 &fuzz);
 109         if (data_present)
 110                 touchscreen_set_params(input, axis, maximum, fuzz);
 111
 112         if (!prop)
 113                 return;
 114
 115         axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
 116
 117         prop->max_x = input_abs_get_max(input, axis);
 118         prop->max_y = input_abs_get_max(input, axis + 1);
 119         prop->invert_x =
 120                 device_property_read_bool(dev, "touchscreen-inverted-x");
 121         prop->invert_y =
 122                 device_property_read_bool(dev, "touchscreen-inverted-y");
 123         prop->swap_x_y =
 124                 device_property_read_bool(dev, "touchscreen-swapped-x-y");
 125
 126         if (prop->swap_x_y)
 127                 swap(input->absinfo[axis], input->absinfo[axis + 1]);
 128 }
 129 EXPORT_SYMBOL(touchscreen_parse_properties);
 130
 131 static void
 132 touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
 133                               unsigned int *x, unsigned int *y)
 134 {
 135         if (prop->invert_x)
 136                 *x = prop->max_x - *x;
 137
 138         if (prop->invert_y)
 139                 *y = prop->max_y - *y;
 140
 141         if (prop->swap_x_y)
 142                 swap(*x, *y);
 143 }
 144
 145 /**
 146  * touchscreen_set_mt_pos - Set input_mt_pos coordinates
 147  * @pos: input_mt_pos to set coordinates of
 148  * @prop: pointer to a struct touchscreen_properties
 149  * @x: X coordinate to store in pos
 150  * @y: Y coordinate to store in pos
 151  *
 152  * Adjust the passed in x and y values applying any axis inversion and
 153  * swapping requested in the passed in touchscreen_properties and store
 154  * the result in a struct input_mt_pos.
 155  */
 156 void touchscreen_set_mt_pos(struct input_mt_pos *pos,
 157                             const struct touchscreen_properties *prop,
 158                             unsigned int x, unsigned int y)
 159 {
 160         touchscreen_apply_prop_to_x_y(prop, &x, &y);
 161         pos->x = x;
 162         pos->y = y;
 163 }
 164 EXPORT_SYMBOL(touchscreen_set_mt_pos);
 165
 166 /**
 167  * touchscreen_report_pos - Report touchscreen coordinates
 168  * @input: input_device to report coordinates for
 169  * @prop: pointer to a struct touchscreen_properties
 170  * @x: X coordinate to report
 171  * @y: Y coordinate to report
 172  * @multitouch: Report coordinates on single-touch or multi-touch axes
 173  *
 174  * Adjust the passed in x and y values applying any axis inversion and
 175  * swapping requested in the passed in touchscreen_properties and then
 176  * report the resulting coordinates on the input_dev's x and y axis.
 177  */
 178 void touchscreen_report_pos(struct input_dev *input,
 179                             const struct touchscreen_properties *prop,
 180                             unsigned int x, unsigned int y,
 181                             bool multitouch)
 182 {
 183         touchscreen_apply_prop_to_x_y(prop, &x, &y);
 184         input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
 185         input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
 186 }
 187 EXPORT_SYMBOL(touchscreen_report_pos);