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/input/matrix_keypad.h>
  27
  28static bool matrix_keypad_map_key(struct input_dev *input_dev,
  29                                  unsigned int rows, unsigned int cols,
  30                                  unsigned int row_shift, unsigned int key)
  31{
  32        unsigned short *keymap = input_dev->keycode;
  33        unsigned int row = KEY_ROW(key);
  34        unsigned int col = KEY_COL(key);
  35        unsigned short code = KEY_VAL(key);
  36
  37        if (row >= rows || col >= cols) {
  38                dev_err(input_dev->dev.parent,
  39                        "%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
  40                        __func__, key, row, col, rows, cols);
  41                return false;
  42        }
  43
  44        keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
  45        __set_bit(code, input_dev->keybit);
  46
  47        return true;
  48}
  49
  50#ifdef CONFIG_OF
  51static int matrix_keypad_parse_of_keymap(const char *propname,
  52                                         unsigned int rows, unsigned int cols,
  53                                         struct input_dev *input_dev)
  54{
  55        struct device *dev = input_dev->dev.parent;
  56        struct device_node *np = dev->of_node;
  57        unsigned int row_shift = get_count_order(cols);
  58        unsigned int max_keys = rows << row_shift;
  59        unsigned int proplen, i, size;
  60        const __be32 *prop;
  61
  62        if (!np)
  63                return -ENOENT;
  64
  65        if (!propname)
  66                propname = "linux,keymap";
  67
  68        prop = of_get_property(np, propname, &proplen);
  69        if (!prop) {
  70                dev_err(dev, "OF: %s property not defined in %s\n",
  71                        propname, np->full_name);
  72                return -ENOENT;
  73        }
  74
  75        if (proplen % sizeof(u32)) {
  76                dev_err(dev, "OF: Malformed keycode property %s in %s\n",
  77                        propname, np->full_name);
  78                return -EINVAL;
  79        }
  80
  81        size = proplen / sizeof(u32);
  82        if (size > max_keys) {
  83                dev_err(dev, "OF: %s size overflow\n", propname);
  84                return -EINVAL;
  85        }
  86
  87        for (i = 0; i < size; i++) {
  88                unsigned int key = be32_to_cpup(prop + i);
  89
  90                if (!matrix_keypad_map_key(input_dev, rows, cols,
  91                                           row_shift, key))
  92                        return -EINVAL;
  93        }
  94
  95        return 0;
  96}
  97#else
  98static int matrix_keypad_parse_of_keymap(const char *propname,
  99                                         unsigned int rows, unsigned int cols,
 100                                         struct input_dev *input_dev)
 101{
 102        return -ENOSYS;
 103}
 104#endif
 105
 106/**
 107 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 108 * @keymap_data: keymap supplied by the platform code
 109 * @keymap_name: name of device tree property containing keymap (if device
 110 *      tree support is enabled).
 111 * @rows: number of rows in target keymap array
 112 * @cols: number of cols in target keymap array
 113 * @keymap: expanded version of keymap that is suitable for use by
 114 * matrix keyboard driver
 115 * @input_dev: input devices for which we are setting up the keymap
 116 *
 117 * This function converts platform keymap (encoded with KEY() macro) into
 118 * an array of keycodes that is suitable for using in a standard matrix
 119 * keyboard driver that uses row and col as indices.
 120 *
 121 * If @keymap_data is not supplied and device tree support is enabled
 122 * it will attempt load the keymap from property specified by @keymap_name
 123 * argument (or "linux,keymap" if @keymap_name is %NULL).
 124 *
 125 * Callers are expected to set up input_dev->dev.parent before calling this
 126 * function.
 127 */
 128int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 129                               const char *keymap_name,
 130                               unsigned int rows, unsigned int cols,
 131                               unsigned short *keymap,
 132                               struct input_dev *input_dev)
 133{
 134        unsigned int row_shift = get_count_order(cols);
 135        int i;
 136        int error;
 137
 138        input_dev->keycode = keymap;
 139        input_dev->keycodesize = sizeof(*keymap);
 140        input_dev->keycodemax = rows << row_shift;
 141
 142        __set_bit(EV_KEY, input_dev->evbit);
 143
 144        if (keymap_data) {
 145                for (i = 0; i < keymap_data->keymap_size; i++) {
 146                        unsigned int key = keymap_data->keymap[i];
 147
 148                        if (!matrix_keypad_map_key(input_dev, rows, cols,
 149                                                   row_shift, key))
 150                                return -EINVAL;
 151                }
 152        } else {
 153                error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
 154                                                      input_dev);
 155                if (error)
 156                        return error;
 157        }
 158
 159        __clear_bit(KEY_RESERVED, input_dev->keybit);
 160
 161        return 0;
 162}
 163EXPORT_SYMBOL(matrix_keypad_build_keymap);
 164
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