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/gfp.h>
  22 #include <linux/kernel.h>
  23 #include <linux/types.h>
  24 #include <linux/input.h>
  25 #include <linux/of.h>
  26 #include <linux/export.h>
  27 #include <linux/module.h>
  28 #include <linux/input/matrix_keypad.h>
  29
  30 static bool matrix_keypad_map_key(struct input_dev *input_dev,
  31                                   unsigned int rows, unsigned int cols,
  32                                   unsigned int row_shift, unsigned int key)
  33 {
  34         unsigned short *keymap = input_dev->keycode;
  35         unsigned int row = KEY_ROW(key);
  36         unsigned int col = KEY_COL(key);
  37         unsigned short code = KEY_VAL(key);
  38
  39         if (row >= rows || col >= cols) {
  40                 dev_err(input_dev->dev.parent,
  41                         "%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
  42                         __func__, key, row, col, rows, cols);
  43                 return false;
  44         }
  45
  46         keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
  47         __set_bit(code, input_dev->keybit);
  48
  49         return true;
  50 }
  51
  52 #ifdef CONFIG_OF
  53 static int matrix_keypad_parse_of_keymap(const char *propname,
  54                                          unsigned int rows, unsigned int cols,
  55                                          struct input_dev *input_dev)
  56 {
  57         struct device *dev = input_dev->dev.parent;
  58         struct device_node *np = dev->of_node;
  59         unsigned int row_shift = get_count_order(cols);
  60         unsigned int max_keys = rows << row_shift;
  61         unsigned int proplen, i, size;
  62         const __be32 *prop;
  63
  64         if (!np)
  65                 return -ENOENT;
  66
  67         if (!propname)
  68                 propname = "linux,keymap";
  69
  70         prop = of_get_property(np, propname, &proplen);
  71         if (!prop) {
  72                 dev_err(dev, "OF: %s property not defined in %s\n",
  73                         propname, np->full_name);
  74                 return -ENOENT;
  75         }
  76
  77         if (proplen % sizeof(u32)) {
  78                 dev_err(dev, "OF: Malformed keycode property %s in %s\n",
  79                         propname, np->full_name);
  80                 return -EINVAL;
  81         }
  82
  83         size = proplen / sizeof(u32);
  84         if (size > max_keys) {
  85                 dev_err(dev, "OF: %s size overflow\n", propname);
  86                 return -EINVAL;
  87         }
  88
  89         for (i = 0; i < size; i++) {
  90                 unsigned int key = be32_to_cpup(prop + i);
  91
  92                 if (!matrix_keypad_map_key(input_dev, rows, cols,
  93                                            row_shift, key))
  94                         return -EINVAL;
  95         }
  96
  97         return 0;
  98 }
  99 #else
 100 static int matrix_keypad_parse_of_keymap(const char *propname,
 101                                          unsigned int rows, unsigned int cols,
 102                                          struct input_dev *input_dev)
 103 {
 104         return -ENOSYS;
 105 }
 106 #endif
 107
 108 /**
 109  * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 110  * @keymap_data: keymap supplied by the platform code
 111  * @keymap_name: name of device tree property containing keymap (if device
 112  *      tree support is enabled).
 113  * @rows: number of rows in target keymap array
 114  * @cols: number of cols in target keymap array
 115  * @keymap: expanded version of keymap that is suitable for use by
 116  * matrix keyboard driver
 117  * @input_dev: input devices for which we are setting up the keymap
 118  *
 119  * This function converts platform keymap (encoded with KEY() macro) into
 120  * an array of keycodes that is suitable for using in a standard matrix
 121  * keyboard driver that uses row and col as indices.
 122  *
 123  * If @keymap_data is not supplied and device tree support is enabled
 124  * it will attempt load the keymap from property specified by @keymap_name
 125  * argument (or "linux,keymap" if @keymap_name is %NULL).
 126  *
 127  * If @keymap is %NULL the function will automatically allocate managed
 128  * block of memory to store the keymap. This memory will be associated with
 129  * the parent device and automatically freed when device unbinds from the
 130  * driver.
 131  *
 132  * Callers are expected to set up input_dev->dev.parent before calling this
 133  * function.
 134  */
 135 int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 136                                const char *keymap_name,
 137                                unsigned int rows, unsigned int cols,
 138                                unsigned short *keymap,
 139                                struct input_dev *input_dev)
 140 {
 141         unsigned int row_shift = get_count_order(cols);
 142         size_t max_keys = rows << row_shift;
 143         int i;
 144         int error;
 145
 146         if (WARN_ON(!input_dev->dev.parent))
 147                 return -EINVAL;
 148
 149         if (!keymap) {
 150                 keymap = devm_kzalloc(input_dev->dev.parent,
 151                                       max_keys * sizeof(*keymap),
 152                                       GFP_KERNEL);
 153                 if (!keymap) {
 154                         dev_err(input_dev->dev.parent,
 155                                 "Unable to allocate memory for keymap");
 156                         return -ENOMEM;
 157                 }
 158         }
 159
 160         input_dev->keycode = keymap;
 161         input_dev->keycodesize = sizeof(*keymap);
 162         input_dev->keycodemax = max_keys;
 163
 164         __set_bit(EV_KEY, input_dev->evbit);
 165
 166         if (keymap_data) {
 167                 for (i = 0; i < keymap_data->keymap_size; i++) {
 168                         unsigned int key = keymap_data->keymap[i];
 169
 170                         if (!matrix_keypad_map_key(input_dev, rows, cols,
 171                                                    row_shift, key))
 172                                 return -EINVAL;
 173                 }
 174         } else {
 175                 error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
 176                                                       input_dev);
 177                 if (error)
 178                         return error;
 179         }
 180
 181         __clear_bit(KEY_RESERVED, input_dev->keybit);
 182
 183         return 0;
 184 }
 185 EXPORT_SYMBOL(matrix_keypad_build_keymap);
 186
 187 MODULE_LICENSE("GPL");