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/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
  30static 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
  53int matrix_keypad_parse_of_params(struct device *dev,
  54                                  unsigned int *rows, unsigned int *cols)
  55{
  56        struct device_node *np = dev->of_node;
  57
  58        if (!np) {
  59                dev_err(dev, "missing DT data");
  60                return -EINVAL;
  61        }
  62        of_property_read_u32(np, "keypad,num-rows", rows);
  63        of_property_read_u32(np, "keypad,num-columns", cols);
  64        if (!*rows || !*cols) {
  65                dev_err(dev, "number of keypad rows/columns not specified\n");
  66                return -EINVAL;
  67        }
  68
  69        return 0;
  70}
  71EXPORT_SYMBOL_GPL(matrix_keypad_parse_of_params);
  72
  73static int matrix_keypad_parse_of_keymap(const char *propname,
  74                                         unsigned int rows, unsigned int cols,
  75                                         struct input_dev *input_dev)
  76{
  77        struct device *dev = input_dev->dev.parent;
  78        struct device_node *np = dev->of_node;
  79        unsigned int row_shift = get_count_order(cols);
  80        unsigned int max_keys = rows << row_shift;
  81        unsigned int proplen, i, size;
  82        const __be32 *prop;
  83
  84        if (!np)
  85                return -ENOENT;
  86
  87        if (!propname)
  88                propname = "linux,keymap";
  89
  90        prop = of_get_property(np, propname, &proplen);
  91        if (!prop) {
  92                dev_err(dev, "OF: %s property not defined in %s\n",
  93                        propname, np->full_name);
  94                return -ENOENT;
  95        }
  96
  97        if (proplen % sizeof(u32)) {
  98                dev_err(dev, "OF: Malformed keycode property %s in %s\n",
  99                        propname, np->full_name);
 100                return -EINVAL;
 101        }
 102
 103        size = proplen / sizeof(u32);
 104        if (size > max_keys) {
 105                dev_err(dev, "OF: %s size overflow\n", propname);
 106                return -EINVAL;
 107        }
 108
 109        for (i = 0; i < size; i++) {
 110                unsigned int key = be32_to_cpup(prop + i);
 111
 112                if (!matrix_keypad_map_key(input_dev, rows, cols,
 113                                           row_shift, key))
 114                        return -EINVAL;
 115        }
 116
 117        return 0;
 118}
 119#else
 120static int matrix_keypad_parse_of_keymap(const char *propname,
 121                                         unsigned int rows, unsigned int cols,
 122                                         struct input_dev *input_dev)
 123{
 124        return -ENOSYS;
 125}
 126#endif
 127
 128/**
 129 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 130 * @keymap_data: keymap supplied by the platform code
 131 * @keymap_name: name of device tree property containing keymap (if device
 132 *      tree support is enabled).
 133 * @rows: number of rows in target keymap array
 134 * @cols: number of cols in target keymap array
 135 * @keymap: expanded version of keymap that is suitable for use by
 136 * matrix keyboard driver
 137 * @input_dev: input devices for which we are setting up the keymap
 138 *
 139 * This function converts platform keymap (encoded with KEY() macro) into
 140 * an array of keycodes that is suitable for using in a standard matrix
 141 * keyboard driver that uses row and col as indices.
 142 *
 143 * If @keymap_data is not supplied and device tree support is enabled
 144 * it will attempt load the keymap from property specified by @keymap_name
 145 * argument (or "linux,keymap" if @keymap_name is %NULL).
 146 *
 147 * If @keymap is %NULL the function will automatically allocate managed
 148 * block of memory to store the keymap. This memory will be associated with
 149 * the parent device and automatically freed when device unbinds from the
 150 * driver.
 151 *
 152 * Callers are expected to set up input_dev->dev.parent before calling this
 153 * function.
 154 */
 155int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 156                               const char *keymap_name,
 157                               unsigned int rows, unsigned int cols,
 158                               unsigned short *keymap,
 159                               struct input_dev *input_dev)
 160{
 161        unsigned int row_shift = get_count_order(cols);
 162        size_t max_keys = rows << row_shift;
 163        int i;
 164        int error;
 165
 166        if (WARN_ON(!input_dev->dev.parent))
 167                return -EINVAL;
 168
 169        if (!keymap) {
 170                keymap = devm_kzalloc(input_dev->dev.parent,
 171                                      max_keys * sizeof(*keymap),
 172                                      GFP_KERNEL);
 173                if (!keymap) {
 174                        dev_err(input_dev->dev.parent,
 175                                "Unable to allocate memory for keymap");
 176                        return -ENOMEM;
 177                }
 178        }
 179
 180        input_dev->keycode = keymap;
 181        input_dev->keycodesize = sizeof(*keymap);
 182        input_dev->keycodemax = max_keys;
 183
 184        __set_bit(EV_KEY, input_dev->evbit);
 185
 186        if (keymap_data) {
 187                for (i = 0; i < keymap_data->keymap_size; i++) {
 188                        unsigned int key = keymap_data->keymap[i];
 189
 190                        if (!matrix_keypad_map_key(input_dev, rows, cols,
 191                                                   row_shift, key))
 192                                return -EINVAL;
 193                }
 194        } else {
 195                error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
 196                                                      input_dev);
 197                if (error)
 198                        return error;
 199        }
 200
 201        __clear_bit(KEY_RESERVED, input_dev->keybit);
 202
 203        return 0;
 204}
 205EXPORT_SYMBOL(matrix_keypad_build_keymap);
 206
 207MODULE_LICENSE("GPL");
 208
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