LXR linux/drivers/input/touchscreen/of

   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
  18static 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
  36static 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 */
  67void 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}
 130EXPORT_SYMBOL(touchscreen_parse_properties);
 131
 132static void
 133touchscreen_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 */
 157void 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}
 165EXPORT_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 */
 179void 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}
 188EXPORT_SYMBOL(touchscreen_report_pos);
 189
 190MODULE_LICENSE("GPL v2");
 191MODULE_DESCRIPTION("Device-tree helpers functions for touchscreen devices");
 192