drivers/input/matrix-keymap.c

   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
  28 static 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
  51 static 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
  98 static 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  */
 128 int 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 }
 163 EXPORT_SYMBOL(matrix_keypad_build_keymap);