2 * Manage Keyboard Matrices
4 * Copyright (c) 2012 The Chromium OS Authors.
5 * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
7 * See file CREDITS for list of people who contributed to this
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 #include <key_matrix.h>
29 #include <linux/input.h>
32 * Determine if the current keypress configuration can cause key ghosting
34 * We figure this out by seeing if we have two or more keys in the same
35 * column, as well as two or more keys in the same row.
37 * @param config Keyboard matrix config
38 * @param keys List of keys to check
39 * @param valid Number of valid keypresses to check
40 * @return 0 if no ghosting is possible, 1 if it is
42 static int has_ghosting(struct key_matrix *config, struct key_matrix_key *keys,
45 int key_in_same_col = 0, key_in_same_row = 0;
48 for (i = 0; i < valid; i++) {
50 * Find 2 keys such that one key is in the same row
51 * and the other is in the same column as the i-th key.
53 for (j = i + 1; j < valid; j++) {
54 if (keys[j].col == keys[i].col)
56 if (keys[j].row == keys[i].row)
61 if (key_in_same_col && key_in_same_row)
67 int key_matrix_decode(struct key_matrix *config, struct key_matrix_key keys[],
68 int num_keys, int keycode[], int max_keycodes)
74 debug("%s: num_keys = %d\n", __func__, num_keys);
75 keymap = config->plain_keycode;
76 for (valid = upto = 0; upto < num_keys; upto++) {
77 struct key_matrix_key *key = &keys[upto];
79 debug(" valid=%d, row=%d, col=%d\n", key->valid, key->row,
83 pos = key->row * config->num_cols + key->col;
84 if (config->fn_keycode && pos == config->fn_pos)
85 keymap = config->fn_keycode;
87 /* Convert the (row, col) values into a keycode */
88 if (valid < max_keycodes)
89 keycode[valid++] = keymap[pos];
90 debug(" keycode=%d\n", keymap[pos]);
93 /* For a ghost key config, ignore the keypresses for this iteration. */
94 if (valid >= 3 && has_ghosting(config, keys, valid)) {
96 debug(" ghosting detected!\n");
98 debug(" %d valid keycodes found\n", valid);
104 * Create a new keycode map from some provided data
106 * This decodes a keycode map in the format used by the fdt, which is one
107 * word per entry, with the row, col and keycode encoded in that word.
109 * We create a (row x col) size byte array with each entry containing the
110 * keycode for that (row, col). We also search for map_keycode and return
111 * its position if found (this is used for finding the Fn key).
113 * @param config Key matrix dimensions structure
114 * @param data Keycode data
115 * @param len Number of entries in keycode table
116 * @param map_keycode Key code to find in the map
117 * @param pos Returns position of map_keycode, if found, else -1
118 * @return map Pointer to allocated map
120 static uchar *create_keymap(struct key_matrix *config, u32 *data, int len,
121 int map_keycode, int *pos)
127 map = (uchar *)calloc(1, config->key_count);
129 debug("%s: failed to malloc %d bytes\n", __func__,
134 for (; len >= sizeof(u32); data++, len -= 4) {
135 u32 tmp = fdt32_to_cpu(*data);
136 int key_code, row, col;
139 row = (tmp >> 24) & 0xff;
140 col = (tmp >> 16) & 0xff;
141 key_code = tmp & 0xffff;
142 entry = row * config->num_cols + col;
143 map[entry] = key_code;
144 if (pos && map_keycode == key_code)
151 int key_matrix_decode_fdt(struct key_matrix *config, const void *blob,
154 const struct fdt_property *prop;
157 /* Check each property name for ones that we understand */
158 for (offset = fdt_first_property_offset(blob, node);
160 offset = fdt_next_property_offset(blob, offset)) {
164 prop = fdt_get_property_by_offset(blob, offset, NULL);
165 name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
168 /* Name needs to match "1,<type>keymap" */
169 debug("%s: property '%s'\n", __func__, name);
170 if (strncmp(name, "1,", 2) || len < 8 ||
171 strcmp(name + len - 6, "keymap"))
176 config->plain_keycode = create_keymap(config,
177 (u32 *)prop->data, fdt32_to_cpu(prop->len),
178 KEY_FN, &config->fn_pos);
179 } else if (0 == strncmp(name + 2, "fn-", len)) {
180 config->fn_keycode = create_keymap(config,
181 (u32 *)prop->data, fdt32_to_cpu(prop->len),
184 debug("%s: unrecognised property '%s'\n", __func__,
188 debug("%s: Decoded key maps %p, %p from fdt\n", __func__,
189 config->plain_keycode, config->fn_keycode);
191 if (!config->plain_keycode) {
192 debug("%s: cannot find keycode-plain map\n", __func__);
199 int key_matrix_init(struct key_matrix *config, int rows, int cols)
201 memset(config, '\0', sizeof(*config));
202 config->num_rows = rows;
203 config->num_cols = cols;
204 config->key_count = rows * cols;
205 assert(config->key_count > 0);