linux/drivers/input/matrix-keymap.c
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   1/*
   2 * Helpers for matrix keyboard bindings
   3 *
   4 * Copyright (C) 2012 Google, Inc
   5 *
   6 * Author:
   7 *      Olof Johansson <olof@lixom.net>
   8 *
   9 * This software is licensed under the terms of the GNU General Public
  10 * License version 2, as published by the Free Software Foundation, and
  11 * may be copied, distributed, and modified under those terms.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 */
  19
  20#include <linux/device.h>
  21#include <linux/kernel.h>
  22#include <linux/types.h>
  23#include <linux/input.h>
  24#include <linux/of.h>
  25#include <linux/export.h>
  26#include <linux/module.h>
  27#include <linux/input/matrix_keypad.h>
  28
  29static bool matrix_keypad_map_key(struct input_dev *input_dev,
  30                                  unsigned int rows, unsigned int cols,
  31                                  unsigned int row_shift, unsigned int key)
  32{
  33        unsigned short *keymap = input_dev->keycode;
  34        unsigned int row = KEY_ROW(key);
  35        unsigned int col = KEY_COL(key);
  36        unsigned short code = KEY_VAL(key);
  37
  38        if (row >= rows || col >= cols) {
  39                dev_err(input_dev->dev.parent,
  40                        "%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
  41                        __func__, key, row, col, rows, cols);
  42                return false;
  43        }
  44
  45        keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
  46        __set_bit(code, input_dev->keybit);
  47
  48        return true;
  49}
  50
  51#ifdef CONFIG_OF
  52static int matrix_keypad_parse_of_keymap(const char *propname,
  53                                         unsigned int rows, unsigned int cols,
  54                                         struct input_dev *input_dev)
  55{
  56        struct device *dev = input_dev->dev.parent;
  57        struct device_node *np = dev->of_node;
  58        unsigned int row_shift = get_count_order(cols);
  59        unsigned int max_keys = rows << row_shift;
  60        unsigned int proplen, i, size;
  61        const __be32 *prop;
  62
  63        if (!np)
  64                return -ENOENT;
  65
  66        if (!propname)
  67                propname = "linux,keymap";
  68
  69        prop = of_get_property(np, propname, &proplen);
  70        if (!prop) {
  71                dev_err(dev, "OF: %s property not defined in %s\n",
  72                        propname, np->full_name);
  73                return -ENOENT;
  74        }
  75
  76        if (proplen % sizeof(u32)) {
  77                dev_err(dev, "OF: Malformed keycode property %s in %s\n",
  78                        propname, np->full_name);
  79                return -EINVAL;
  80        }
  81
  82        size = proplen / sizeof(u32);
  83        if (size > max_keys) {
  84                dev_err(dev, "OF: %s size overflow\n", propname);
  85                return -EINVAL;
  86        }
  87
  88        for (i = 0; i < size; i++) {
  89                unsigned int key = be32_to_cpup(prop + i);
  90
  91                if (!matrix_keypad_map_key(input_dev, rows, cols,
  92                                           row_shift, key))
  93                        return -EINVAL;
  94        }
  95
  96        return 0;
  97}
  98#else
  99static int matrix_keypad_parse_of_keymap(const char *propname,
 100                                         unsigned int rows, unsigned int cols,
 101                                         struct input_dev *input_dev)
 102{
 103        return -ENOSYS;
 104}
 105#endif
 106
 107/**
 108 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 109 * @keymap_data: keymap supplied by the platform code
 110 * @keymap_name: name of device tree property containing keymap (if device
 111 *      tree support is enabled).
 112 * @rows: number of rows in target keymap array
 113 * @cols: number of cols in target keymap array
 114 * @keymap: expanded version of keymap that is suitable for use by
 115 * matrix keyboard driver
 116 * @input_dev: input devices for which we are setting up the keymap
 117 *
 118 * This function converts platform keymap (encoded with KEY() macro) into
 119 * an array of keycodes that is suitable for using in a standard matrix
 120 * keyboard driver that uses row and col as indices.
 121 *
 122 * If @keymap_data is not supplied and device tree support is enabled
 123 * it will attempt load the keymap from property specified by @keymap_name
 124 * argument (or "linux,keymap" if @keymap_name is %NULL).
 125 *
 126 * Callers are expected to set up input_dev->dev.parent before calling this
 127 * function.
 128 */
 129int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 130                               const char *keymap_name,
 131                               unsigned int rows, unsigned int cols,
 132                               unsigned short *keymap,
 133                               struct input_dev *input_dev)
 134{
 135        unsigned int row_shift = get_count_order(cols);
 136        int i;
 137        int error;
 138
 139        input_dev->keycode = keymap;
 140        input_dev->keycodesize = sizeof(*keymap);
 141        input_dev->keycodemax = rows << row_shift;
 142
 143        __set_bit(EV_KEY, input_dev->evbit);
 144
 145        if (keymap_data) {
 146                for (i = 0; i < keymap_data->keymap_size; i++) {
 147                        unsigned int key = keymap_data->keymap[i];
 148
 149                        if (!matrix_keypad_map_key(input_dev, rows, cols,
 150                                                   row_shift, key))
 151                                return -EINVAL;
 152                }
 153        } else {
 154                error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
 155                                                      input_dev);
 156                if (error)
 157                        return error;
 158        }
 159
 160        __clear_bit(KEY_RESERVED, input_dev->keybit);
 161
 162        return 0;
 163}
 164EXPORT_SYMBOL(matrix_keypad_build_keymap);
 165
 166MODULE_LICENSE("GPL");
 167
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