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 if (code > KEY_MAX) { 39 dev_err(input_dev->dev.parent, 40 "%s: invalid keycode %u in keymap entry 0x%x\n", 41 __func__, code, key); 42 return false; 43 } 44 45 keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code; 46 __set_bit(code, input_dev->keybit); 47 48 return true; 49 } 50 51 /** 52 * matrix_keypad_parse_properties() - Read properties of matrix keypad 53 * 54 * @dev: Device containing properties 55 * @rows: Returns number of matrix rows 56 * @cols: Returns number of matrix columns 57 * @return 0 if OK, <0 on error 58 */ 59 int matrix_keypad_parse_properties(struct device *dev, 60 unsigned int *rows, unsigned int *cols) 61 { 62 *rows = *cols = 0; 63 64 device_property_read_u32(dev, "keypad,num-rows", rows); 65 device_property_read_u32(dev, "keypad,num-columns", cols); 66 67 if (!*rows || !*cols) { 68 dev_err(dev, "number of keypad rows/columns not specified\n"); 69 return -EINVAL; 70 } 71 72 return 0; 73 } 74 EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties); 75 76 static int matrix_keypad_parse_keymap(const char *propname, 77 unsigned int rows, unsigned int cols, 78 struct input_dev *input_dev) 79 { 80 struct device *dev = input_dev->dev.parent; 81 unsigned int row_shift = get_count_order(cols); 82 unsigned int max_keys = rows << row_shift; 83 int i; 84 int size; 85 int error; 86 87 if (!propname) 88 propname = "linux,keymap"; 89 90 size = device_property_count_u32(dev, propname); 91 if (size <= 0) { 92 dev_err(dev, "missing or malformed property %s: %d\n", 93 propname, size); 94 return size < 0 ? size : -EINVAL; 95 } 96 97 if (size > max_keys) { 98 dev_err(dev, "%s size overflow (%d vs max %u)\n", 99 propname, size, max_keys); 100 return -EINVAL; 101 } 102 103 u32 *keys __free(kfree) = kmalloc_array(size, sizeof(*keys), GFP_KERNEL); 104 if (!keys) 105 return -ENOMEM; 106 107 error = device_property_read_u32_array(dev, propname, keys, size); 108 if (error) { 109 dev_err(dev, "failed to read %s property: %d\n", 110 propname, error); 111 return error; 112 } 113 114 for (i = 0; i < size; i++) { 115 if (!matrix_keypad_map_key(input_dev, rows, cols, 116 row_shift, keys[i])) 117 return -EINVAL; 118 } 119 120 return 0; 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_kzalloc_objs(input_dev->dev.parent, *keymap, 166 max_keys); 167 if (!keymap) { 168 dev_err(input_dev->dev.parent, 169 "Unable to allocate memory for keymap"); 170 return -ENOMEM; 171 } 172 } 173 174 input_dev->keycode = keymap; 175 input_dev->keycodesize = sizeof(*keymap); 176 input_dev->keycodemax = max_keys; 177 178 __set_bit(EV_KEY, input_dev->evbit); 179 180 if (keymap_data) { 181 for (i = 0; i < keymap_data->keymap_size; i++) { 182 unsigned int key = keymap_data->keymap[i]; 183 184 if (!matrix_keypad_map_key(input_dev, rows, cols, 185 row_shift, key)) 186 return -EINVAL; 187 } 188 } else { 189 error = matrix_keypad_parse_keymap(keymap_name, rows, cols, 190 input_dev); 191 if (error) 192 return error; 193 } 194 195 __clear_bit(KEY_RESERVED, input_dev->keybit); 196 197 return 0; 198 } 199 EXPORT_SYMBOL(matrix_keypad_build_keymap); 200 201 MODULE_DESCRIPTION("Helpers for matrix keyboard bindings"); 202 MODULE_LICENSE("GPL"); 203