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         int i;
  77         int size;
  78         int error;
  79
  80         if (!propname)
  81                 propname = "linux,keymap";
  82
  83         size = device_property_count_u32(dev, propname);
  84         if (size <= 0) {
  85                 dev_err(dev, "missing or malformed property %s: %d\n",
  86                         propname, size);
  87                 return size < 0 ? size : -EINVAL;
  88         }
  89
  90         if (size > max_keys) {
  91                 dev_err(dev, "%s size overflow (%d vs max %u)\n",
  92                         propname, size, max_keys);
  93                 return -EINVAL;
  94         }
  95
  96         u32 *keys __free(kfree) = kmalloc_array(size, sizeof(*keys), GFP_KERNEL);
  97         if (!keys)
  98                 return -ENOMEM;
  99
 100         error = device_property_read_u32_array(dev, propname, keys, size);
 101         if (error) {
 102                 dev_err(dev, "failed to read %s property: %d\n",
 103                         propname, error);
 104                 return error;
 105         }
 106
 107         for (i = 0; i < size; i++) {
 108                 if (!matrix_keypad_map_key(input_dev, rows, cols,
 109                                            row_shift, keys[i]))
 110                         return -EINVAL;
 111         }
 112
 113         return 0;
 114 }
 115
 116 /**
 117  * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 118  * @keymap_data: keymap supplied by the platform code
 119  * @keymap_name: name of device tree property containing keymap (if device
 120  *      tree support is enabled).
 121  * @rows: number of rows in target keymap array
 122  * @cols: number of cols in target keymap array
 123  * @keymap: expanded version of keymap that is suitable for use by
 124  * matrix keyboard driver
 125  * @input_dev: input devices for which we are setting up the keymap
 126  *
 127  * This function converts platform keymap (encoded with KEY() macro) into
 128  * an array of keycodes that is suitable for using in a standard matrix
 129  * keyboard driver that uses row and col as indices.
 130  *
 131  * If @keymap_data is not supplied and device tree support is enabled
 132  * it will attempt load the keymap from property specified by @keymap_name
 133  * argument (or "linux,keymap" if @keymap_name is %NULL).
 134  *
 135  * If @keymap is %NULL the function will automatically allocate managed
 136  * block of memory to store the keymap. This memory will be associated with
 137  * the parent device and automatically freed when device unbinds from the
 138  * driver.
 139  *
 140  * Callers are expected to set up input_dev->dev.parent before calling this
 141  * function.
 142  */
 143 int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 144                                const char *keymap_name,
 145                                unsigned int rows, unsigned int cols,
 146                                unsigned short *keymap,
 147                                struct input_dev *input_dev)
 148 {
 149         unsigned int row_shift = get_count_order(cols);
 150         size_t max_keys = rows << row_shift;
 151         int i;
 152         int error;
 153
 154         if (WARN_ON(!input_dev->dev.parent))
 155                 return -EINVAL;
 156
 157         if (!keymap) {
 158                 keymap = devm_kcalloc(input_dev->dev.parent,
 159                                       max_keys, sizeof(*keymap),
 160                                       GFP_KERNEL);
 161                 if (!keymap) {
 162                         dev_err(input_dev->dev.parent,
 163                                 "Unable to allocate memory for keymap");
 164                         return -ENOMEM;
 165                 }
 166         }
 167
 168         input_dev->keycode = keymap;
 169         input_dev->keycodesize = sizeof(*keymap);
 170         input_dev->keycodemax = max_keys;
 171
 172         __set_bit(EV_KEY, input_dev->evbit);
 173
 174         if (keymap_data) {
 175                 for (i = 0; i < keymap_data->keymap_size; i++) {
 176                         unsigned int key = keymap_data->keymap[i];
 177
 178                         if (!matrix_keypad_map_key(input_dev, rows, cols,
 179                                                    row_shift, key))
 180                                 return -EINVAL;
 181                 }
 182         } else {
 183                 error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
 184                                                    input_dev);
 185                 if (error)
 186                         return error;
 187         }
 188
 189         __clear_bit(KEY_RESERVED, input_dev->keybit);
 190
 191         return 0;
 192 }
 193 EXPORT_SYMBOL(matrix_keypad_build_keymap);
 194
 195 MODULE_DESCRIPTION("Helpers for matrix keyboard bindings");
 196 MODULE_LICENSE("GPL");