drivers/input/matrix-keymap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Helpers for matrix keyboard bindings
   4  *
   5  * Copyright (C) 2012 Google, Inc
   6  *
   7  * Author:
   8  *      Olof Johansson <olof@lixom.net>
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/export.h>
  13 #include <linux/gfp.h>
  14 #include <linux/input.h>
  15 #include <linux/input/matrix_keypad.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/property.h>
  19 #include <linux/slab.h>
  20 #include <linux/types.h>
  21
  22 static bool matrix_keypad_map_key(struct input_dev *input_dev,
  23                                   unsigned int rows, unsigned int cols,
  24                                   unsigned int row_shift, unsigned int key)
  25 {
  26         unsigned short *keymap = input_dev->keycode;
  27         unsigned int row = KEY_ROW(key);
  28         unsigned int col = KEY_COL(key);
  29         unsigned short code = KEY_VAL(key);
  30
  31         if (row >= rows || col >= cols) {
  32                 dev_err(input_dev->dev.parent,
  33                         "%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
  34                         __func__, key, row, col, rows, cols);
  35                 return false;
  36         }
  37
  38         keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
  39         __set_bit(code, input_dev->keybit);
  40
  41         return true;
  42 }
  43
  44 /**
  45  * matrix_keypad_parse_properties() - Read properties of matrix keypad
  46  *
  47  * @dev: Device containing properties
  48  * @rows: Returns number of matrix rows
  49  * @cols: Returns number of matrix columns
  50  * @return 0 if OK, <0 on error
  51  */
  52 int matrix_keypad_parse_properties(struct device *dev,
  53                                    unsigned int *rows, unsigned int *cols)
  54 {
  55         *rows = *cols = 0;
  56
  57         device_property_read_u32(dev, "keypad,num-rows", rows);
  58         device_property_read_u32(dev, "keypad,num-columns", cols);
  59
  60         if (!*rows || !*cols) {
  61                 dev_err(dev, "number of keypad rows/columns not specified\n");
  62                 return -EINVAL;
  63         }
  64
  65         return 0;
  66 }
  67 EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties);
  68
  69 static int matrix_keypad_parse_keymap(const char *propname,
  70                                       unsigned int rows, unsigned int cols,
  71                                       struct input_dev *input_dev)
  72 {
  73         struct device *dev = input_dev->dev.parent;
  74         unsigned int row_shift = get_count_order(cols);
  75         unsigned int max_keys = rows << row_shift;
  76         u32 *keys;
  77         int i;
  78         int size;
  79         int retval;
  80
  81         if (!propname)
  82                 propname = "linux,keymap";
  83
  84         size = device_property_count_u32(dev, propname);
  85         if (size <= 0) {
  86                 dev_err(dev, "missing or malformed property %s: %d\n",
  87                         propname, size);
  88                 return size < 0 ? size : -EINVAL;
  89         }
  90
  91         if (size > max_keys) {
  92                 dev_err(dev, "%s size overflow (%d vs max %u)\n",
  93                         propname, size, max_keys);
  94                 return -EINVAL;
  95         }
  96
  97         keys = kmalloc_array(size, sizeof(u32), GFP_KERNEL);
  98         if (!keys)
  99                 return -ENOMEM;
 100
 101         retval = device_property_read_u32_array(dev, propname, keys, size);
 102         if (retval) {
 103                 dev_err(dev, "failed to read %s property: %d\n",
 104                         propname, retval);
 105                 goto out;
 106         }
 107
 108         for (i = 0; i < size; i++) {
 109                 if (!matrix_keypad_map_key(input_dev, rows, cols,
 110                                            row_shift, keys[i])) {
 111                         retval = -EINVAL;
 112                         goto out;
 113                 }
 114         }
 115
 116         retval = 0;
 117
 118 out:
 119         kfree(keys);
 120         return retval;
 121 }
 122
 123 /**
 124  * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 125  * @keymap_data: keymap supplied by the platform code
 126  * @keymap_name: name of device tree property containing keymap (if device
 127  *      tree support is enabled).
 128  * @rows: number of rows in target keymap array
 129  * @cols: number of cols in target keymap array
 130  * @keymap: expanded version of keymap that is suitable for use by
 131  * matrix keyboard driver
 132  * @input_dev: input devices for which we are setting up the keymap
 133  *
 134  * This function converts platform keymap (encoded with KEY() macro) into
 135  * an array of keycodes that is suitable for using in a standard matrix
 136  * keyboard driver that uses row and col as indices.
 137  *
 138  * If @keymap_data is not supplied and device tree support is enabled
 139  * it will attempt load the keymap from property specified by @keymap_name
 140  * argument (or "linux,keymap" if @keymap_name is %NULL).
 141  *
 142  * If @keymap is %NULL the function will automatically allocate managed
 143  * block of memory to store the keymap. This memory will be associated with
 144  * the parent device and automatically freed when device unbinds from the
 145  * driver.
 146  *
 147  * Callers are expected to set up input_dev->dev.parent before calling this
 148  * function.
 149  */
 150 int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 151                                const char *keymap_name,
 152                                unsigned int rows, unsigned int cols,
 153                                unsigned short *keymap,
 154                                struct input_dev *input_dev)
 155 {
 156         unsigned int row_shift = get_count_order(cols);
 157         size_t max_keys = rows << row_shift;
 158         int i;
 159         int error;
 160
 161         if (WARN_ON(!input_dev->dev.parent))
 162                 return -EINVAL;
 163
 164         if (!keymap) {
 165                 keymap = devm_kcalloc(input_dev->dev.parent,
 166                                       max_keys, sizeof(*keymap),
 167                                       GFP_KERNEL);
 168                 if (!keymap) {
 169                         dev_err(input_dev->dev.parent,
 170                                 "Unable to allocate memory for keymap");
 171                         return -ENOMEM;
 172                 }
 173         }
 174
 175         input_dev->keycode = keymap;
 176         input_dev->keycodesize = sizeof(*keymap);
 177         input_dev->keycodemax = max_keys;
 178
 179         __set_bit(EV_KEY, input_dev->evbit);
 180
 181         if (keymap_data) {
 182                 for (i = 0; i < keymap_data->keymap_size; i++) {
 183                         unsigned int key = keymap_data->keymap[i];
 184
 185                         if (!matrix_keypad_map_key(input_dev, rows, cols,
 186                                                    row_shift, key))
 187                                 return -EINVAL;
 188                 }
 189         } else {
 190                 error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
 191                                                    input_dev);
 192                 if (error)
 193                         return error;
 194         }
 195
 196         __clear_bit(KEY_RESERVED, input_dev->keybit);
 197
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(matrix_keypad_build_keymap);
 201
 202 MODULE_LICENSE("GPL");