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 #include <linux/module.h>
  17
  18 static bool touchscreen_get_prop_u32(struct device *dev,
  19                                      const char *property,
  20                                      unsigned int default_value,
  21                                      unsigned int *value)
  22 {
  23         u32 val;
  24         int error;
  25
  26         error = device_property_read_u32(dev, property, &val);
  27         if (error) {
  28                 *value = default_value;
  29                 return false;
  30         }
  31
  32         *value = val;
  33         return true;
  34 }
  35
  36 static void touchscreen_set_params(struct input_dev *dev,
  37                                    unsigned long axis,
  38                                    int max, int fuzz)
  39 {
  40         struct input_absinfo *absinfo;
  41
  42         if (!test_bit(axis, dev->absbit)) {
  43                 dev_warn(&dev->dev,
  44                          "DT specifies parameters but the axis %lu is not set up\n",
  45                          axis);
  46                 return;
  47         }
  48
  49         absinfo = &dev->absinfo[axis];
  50         absinfo->maximum = max;
  51         absinfo->fuzz = fuzz;
  52 }
  53
  54 /**
  55  * touchscreen_parse_properties - parse common touchscreen DT properties
  56  * @input: input device that should be parsed
  57  * @multitouch: specifies whether parsed properties should be applied to
  58  *      single-touch or multi-touch axes
  59  * @prop: pointer to a struct touchscreen_properties into which to store
  60  *      axis swap and invert info for use with touchscreen_report_x_y();
  61  *      or %NULL
  62  *
  63  * This function parses common DT properties for touchscreens and setups the
  64  * input device accordingly. The function keeps previously set up default
  65  * values if no value is specified via DT.
  66  */
  67 void touchscreen_parse_properties(struct input_dev *input, bool multitouch,
  68                                   struct touchscreen_properties *prop)
  69 {
  70         struct device *dev = input->dev.parent;
  71         unsigned int axis;
  72         unsigned int maximum, fuzz;
  73         bool data_present;
  74
  75         input_alloc_absinfo(input);
  76         if (!input->absinfo)
  77                 return;
  78
  79         axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
  80         data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
  81                                                 input_abs_get_max(input,
  82                                                                   axis) + 1,
  83                                                 &maximum) |
  84                        touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
  85                                                 input_abs_get_fuzz(input, axis),
  86                                                 &fuzz);
  87         if (data_present)
  88                 touchscreen_set_params(input, axis, maximum - 1, fuzz);
  89
  90         axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
  91         data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
  92                                                 input_abs_get_max(input,
  93                                                                   axis) + 1,
  94                                                 &maximum) |
  95                        touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
  96                                                 input_abs_get_fuzz(input, axis),
  97                                                 &fuzz);
  98         if (data_present)
  99                 touchscreen_set_params(input, axis, maximum - 1, fuzz);
 100
 101         axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
 102         data_present = touchscreen_get_prop_u32(dev,
 103                                                 "touchscreen-max-pressure",
 104                                                 input_abs_get_max(input, axis),
 105                                                 &maximum) |
 106                        touchscreen_get_prop_u32(dev,
 107                                                 "touchscreen-fuzz-pressure",
 108                                                 input_abs_get_fuzz(input, axis),
 109                                                 &fuzz);
 110         if (data_present)
 111                 touchscreen_set_params(input, axis, maximum, fuzz);
 112
 113         if (!prop)
 114                 return;
 115
 116         axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
 117
 118         prop->max_x = input_abs_get_max(input, axis);
 119         prop->max_y = input_abs_get_max(input, axis + 1);
 120         prop->invert_x =
 121                 device_property_read_bool(dev, "touchscreen-inverted-x");
 122         prop->invert_y =
 123                 device_property_read_bool(dev, "touchscreen-inverted-y");
 124         prop->swap_x_y =
 125                 device_property_read_bool(dev, "touchscreen-swapped-x-y");
 126
 127         if (prop->swap_x_y)
 128                 swap(input->absinfo[axis], input->absinfo[axis + 1]);
 129 }
 130 EXPORT_SYMBOL(touchscreen_parse_properties);
 131
 132 static void
 133 touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop,
 134                               unsigned int *x, unsigned int *y)
 135 {
 136         if (prop->invert_x)
 137                 *x = prop->max_x - *x;
 138
 139         if (prop->invert_y)
 140                 *y = prop->max_y - *y;
 141
 142         if (prop->swap_x_y)
 143                 swap(*x, *y);
 144 }
 145
 146 /**
 147  * touchscreen_set_mt_pos - Set input_mt_pos coordinates
 148  * @pos: input_mt_pos to set coordinates of
 149  * @prop: pointer to a struct touchscreen_properties
 150  * @x: X coordinate to store in pos
 151  * @y: Y coordinate to store in pos
 152  *
 153  * Adjust the passed in x and y values applying any axis inversion and
 154  * swapping requested in the passed in touchscreen_properties and store
 155  * the result in a struct input_mt_pos.
 156  */
 157 void touchscreen_set_mt_pos(struct input_mt_pos *pos,
 158                             const struct touchscreen_properties *prop,
 159                             unsigned int x, unsigned int y)
 160 {
 161         touchscreen_apply_prop_to_x_y(prop, &x, &y);
 162         pos->x = x;
 163         pos->y = y;
 164 }
 165 EXPORT_SYMBOL(touchscreen_set_mt_pos);
 166
 167 /**
 168  * touchscreen_report_pos - Report touchscreen coordinates
 169  * @input: input_device to report coordinates for
 170  * @prop: pointer to a struct touchscreen_properties
 171  * @x: X coordinate to report
 172  * @y: Y coordinate to report
 173  * @multitouch: Report coordinates on single-touch or multi-touch axes
 174  *
 175  * Adjust the passed in x and y values applying any axis inversion and
 176  * swapping requested in the passed in touchscreen_properties and then
 177  * report the resulting coordinates on the input_dev's x and y axis.
 178  */
 179 void touchscreen_report_pos(struct input_dev *input,
 180                             const struct touchscreen_properties *prop,
 181                             unsigned int x, unsigned int y,
 182                             bool multitouch)
 183 {
 184         touchscreen_apply_prop_to_x_y(prop, &x, &y);
 185         input_report_abs(input, multitouch ? ABS_MT_POSITION_X : ABS_X, x);
 186         input_report_abs(input, multitouch ? ABS_MT_POSITION_Y : ABS_Y, y);
 187 }
 188 EXPORT_SYMBOL(touchscreen_report_pos);
 189
 190 MODULE_LICENSE("GPL v2");
 191 MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");