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
  17static 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
  35static 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 *
  59 * This function parses common DT properties for touchscreens and setups the
  60 * input device accordingly. The function keeps previously set up default
  61 * values if no value is specified via DT.
  62 */
  63void touchscreen_parse_properties(struct input_dev *input, bool multitouch)
  64{
  65        struct device *dev = input->dev.parent;
  66        unsigned int axis;
  67        unsigned int maximum, fuzz;
  68        bool data_present;
  69
  70        input_alloc_absinfo(input);
  71        if (!input->absinfo)
  72                return;
  73
  74        axis = multitouch ? ABS_MT_POSITION_X : ABS_X;
  75        data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-x",
  76                                                input_abs_get_max(input,
  77                                                                  axis) + 1,
  78                                                &maximum) |
  79                       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x",
  80                                                input_abs_get_fuzz(input, axis),
  81                                                &fuzz);
  82        if (data_present)
  83                touchscreen_set_params(input, axis, maximum - 1, fuzz);
  84
  85        axis = multitouch ? ABS_MT_POSITION_Y : ABS_Y;
  86        data_present = touchscreen_get_prop_u32(dev, "touchscreen-size-y",
  87                                                input_abs_get_max(input,
  88                                                                  axis) + 1,
  89                                                &maximum) |
  90                       touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y",
  91                                                input_abs_get_fuzz(input, axis),
  92                                                &fuzz);
  93        if (data_present)
  94                touchscreen_set_params(input, axis, maximum - 1, fuzz);
  95
  96        axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE;
  97        data_present = touchscreen_get_prop_u32(dev,
  98                                                "touchscreen-max-pressure",
  99                                                input_abs_get_max(input, axis),
 100                                                &maximum) |
 101                       touchscreen_get_prop_u32(dev,
 102                                                "touchscreen-fuzz-pressure",
 103                                                input_abs_get_fuzz(input, axis),
 104                                                &fuzz);
 105        if (data_present)
 106                touchscreen_set_params(input, axis, maximum, fuzz);
 107}
 108EXPORT_SYMBOL(touchscreen_parse_properties);
 109