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 #include <linux/device.h>
  20 #include <linux/export.h>
  21 #include <linux/gfp.h>
  22 #include <linux/input.h>
  23 #include <linux/input/matrix_keypad.h>
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/property.h>
  27 #include <linux/slab.h>
  28 #include <linux/types.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 /**
  53  * matrix_keypad_parse_properties() - Read properties of matrix keypad
  54  *
  55  * @dev: Device containing properties
  56  * @rows: Returns number of matrix rows
  57  * @cols: Returns number of matrix columns
  58  * @return 0 if OK, <0 on error
  59  */
  60 int matrix_keypad_parse_properties(struct device *dev,
  61                                    unsigned int *rows, unsigned int *cols)
  62 {
  63         *rows = *cols = 0;
  64
  65         device_property_read_u32(dev, "keypad,num-rows", rows);
  66         device_property_read_u32(dev, "keypad,num-columns", cols);
  67
  68         if (!*rows || !*cols) {
  69                 dev_err(dev, "number of keypad rows/columns not specified\n");
  70                 return -EINVAL;
  71         }
  72
  73         return 0;
  74 }
  75 EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties);
  76
  77 static int matrix_keypad_parse_keymap(const char *propname,
  78                                       unsigned int rows, unsigned int cols,
  79                                       struct input_dev *input_dev)
  80 {
  81         struct device *dev = input_dev->dev.parent;
  82         unsigned int row_shift = get_count_order(cols);
  83         unsigned int max_keys = rows << row_shift;
  84         u32 *keys;
  85         int i;
  86         int size;
  87         int retval;
  88
  89         if (!propname)
  90                 propname = "linux,keymap";
  91
  92         size = device_property_read_u32_array(dev, propname, NULL, 0);
  93         if (size <= 0) {
  94                 dev_err(dev, "missing or malformed property %s: %d\n",
  95                         propname, size);
  96                 return size < 0 ? size : -EINVAL;
  97         }
  98
  99         if (size > max_keys) {
 100                 dev_err(dev, "%s size overflow (%d vs max %u)\n",
 101                         propname, size, max_keys);
 102                 return -EINVAL;
 103         }
 104
 105         keys = kmalloc_array(size, sizeof(u32), GFP_KERNEL);
 106         if (!keys)
 107                 return -ENOMEM;
 108
 109         retval = device_property_read_u32_array(dev, propname, keys, size);
 110         if (retval) {
 111                 dev_err(dev, "failed to read %s property: %d\n",
 112                         propname, retval);
 113                 goto out;
 114         }
 115
 116         for (i = 0; i < size; i++) {
 117                 if (!matrix_keypad_map_key(input_dev, rows, cols,
 118                                            row_shift, keys[i])) {
 119                         retval = -EINVAL;
 120                         goto out;
 121                 }
 122         }
 123
 124         retval = 0;
 125
 126 out:
 127         kfree(keys);
 128         return retval;
 129 }
 130
 131 /**
 132  * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 133  * @keymap_data: keymap supplied by the platform code
 134  * @keymap_name: name of device tree property containing keymap (if device
 135  *      tree support is enabled).
 136  * @rows: number of rows in target keymap array
 137  * @cols: number of cols in target keymap array
 138  * @keymap: expanded version of keymap that is suitable for use by
 139  * matrix keyboard driver
 140  * @input_dev: input devices for which we are setting up the keymap
 141  *
 142  * This function converts platform keymap (encoded with KEY() macro) into
 143  * an array of keycodes that is suitable for using in a standard matrix
 144  * keyboard driver that uses row and col as indices.
 145  *
 146  * If @keymap_data is not supplied and device tree support is enabled
 147  * it will attempt load the keymap from property specified by @keymap_name
 148  * argument (or "linux,keymap" if @keymap_name is %NULL).
 149  *
 150  * If @keymap is %NULL the function will automatically allocate managed
 151  * block of memory to store the keymap. This memory will be associated with
 152  * the parent device and automatically freed when device unbinds from the
 153  * driver.
 154  *
 155  * Callers are expected to set up input_dev->dev.parent before calling this
 156  * function.
 157  */
 158 int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 159                                const char *keymap_name,
 160                                unsigned int rows, unsigned int cols,
 161                                unsigned short *keymap,
 162                                struct input_dev *input_dev)
 163 {
 164         unsigned int row_shift = get_count_order(cols);
 165         size_t max_keys = rows << row_shift;
 166         int i;
 167         int error;
 168
 169         if (WARN_ON(!input_dev->dev.parent))
 170                 return -EINVAL;
 171
 172         if (!keymap) {
 173                 keymap = devm_kcalloc(input_dev->dev.parent,
 174                                       max_keys, sizeof(*keymap),
 175                                       GFP_KERNEL);
 176                 if (!keymap) {
 177                         dev_err(input_dev->dev.parent,
 178                                 "Unable to allocate memory for keymap");
 179                         return -ENOMEM;
 180                 }
 181         }
 182
 183         input_dev->keycode = keymap;
 184         input_dev->keycodesize = sizeof(*keymap);
 185         input_dev->keycodemax = max_keys;
 186
 187         __set_bit(EV_KEY, input_dev->evbit);
 188
 189         if (keymap_data) {
 190                 for (i = 0; i < keymap_data->keymap_size; i++) {
 191                         unsigned int key = keymap_data->keymap[i];
 192
 193                         if (!matrix_keypad_map_key(input_dev, rows, cols,
 194                                                    row_shift, key))
 195                                 return -EINVAL;
 196                 }
 197         } else {
 198                 error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
 199                                                    input_dev);
 200                 if (error)
 201                         return error;
 202         }
 203
 204         __clear_bit(KEY_RESERVED, input_dev->keybit);
 205
 206         return 0;
 207 }
 208 EXPORT_SYMBOL(matrix_keypad_build_keymap);
 209
 210 MODULE_LICENSE("GPL");