1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Manage Keyboard Matrices
4 *
5 * Copyright (c) 2012 The Chromium OS Authors.
6 * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
7 */
8
9 #include <common.h>
10 #include <dm.h>
11 #include <key_matrix.h>
12 #include <log.h>
13 #include <malloc.h>
14 #include <linux/input.h>
15
16 /**
17 * Determine if the current keypress configuration can cause key ghosting
18 *
19 * We figure this out by seeing if we have two or more keys in the same
20 * column, as well as two or more keys in the same row.
21 *
22 * @param config Keyboard matrix config
23 * @param keys List of keys to check
24 * @param valid Number of valid keypresses to check
25 * @return 0 if no ghosting is possible, 1 if it is
26 */
has_ghosting(struct key_matrix * config,struct key_matrix_key * keys,int valid)27 static int has_ghosting(struct key_matrix *config, struct key_matrix_key *keys,
28 int valid)
29 {
30 int key_in_same_col = 0, key_in_same_row = 0;
31 int i, j;
32
33 if (!config->ghost_filter || valid < 3)
34 return 0;
35
36 for (i = 0; i < valid; i++) {
37 /*
38 * Find 2 keys such that one key is in the same row
39 * and the other is in the same column as the i-th key.
40 */
41 for (j = i + 1; j < valid; j++) {
42 if (keys[j].col == keys[i].col)
43 key_in_same_col = 1;
44 if (keys[j].row == keys[i].row)
45 key_in_same_row = 1;
46 }
47 }
48
49 if (key_in_same_col && key_in_same_row)
50 return 1;
51 else
52 return 0;
53 }
54
key_matrix_decode(struct key_matrix * config,struct key_matrix_key keys[],int num_keys,int keycode[],int max_keycodes)55 int key_matrix_decode(struct key_matrix *config, struct key_matrix_key keys[],
56 int num_keys, int keycode[], int max_keycodes)
57 {
58 const u8 *keymap;
59 int valid, upto;
60 int pos;
61
62 debug("%s: num_keys = %d\n", __func__, num_keys);
63 keymap = config->plain_keycode;
64 for (valid = upto = 0; upto < num_keys; upto++) {
65 struct key_matrix_key *key = &keys[upto];
66
67 debug(" valid=%d, row=%d, col=%d\n", key->valid, key->row,
68 key->col);
69 if (!key->valid)
70 continue;
71 pos = key->row * config->num_cols + key->col;
72 if (config->fn_keycode && pos == config->fn_pos)
73 keymap = config->fn_keycode;
74
75 /* Convert the (row, col) values into a keycode */
76 if (valid < max_keycodes)
77 keycode[valid++] = keymap[pos];
78 debug(" keycode=%d\n", keymap[pos]);
79 }
80
81 /* For a ghost key config, ignore the keypresses for this iteration. */
82 if (has_ghosting(config, keys, valid)) {
83 valid = 0;
84 debug(" ghosting detected!\n");
85 }
86 debug(" %d valid keycodes found\n", valid);
87
88 return valid;
89 }
90
91 /**
92 * Create a new keycode map from some provided data
93 *
94 * This decodes a keycode map in the format used by the fdt, which is one
95 * word per entry, with the row, col and keycode encoded in that word.
96 *
97 * We create a (row x col) size byte array with each entry containing the
98 * keycode for that (row, col). We also search for map_keycode and return
99 * its position if found (this is used for finding the Fn key).
100 *
101 * @param config Key matrix dimensions structure
102 * @param data Keycode data
103 * @param len Number of entries in keycode table
104 * @param map_keycode Key code to find in the map
105 * @param pos Returns position of map_keycode, if found, else -1
106 * @return map Pointer to allocated map
107 */
create_keymap(struct key_matrix * config,const u32 * data,int len,int map_keycode,int * pos)108 static uchar *create_keymap(struct key_matrix *config, const u32 *data, int len,
109 int map_keycode, int *pos)
110 {
111 uchar *map;
112
113 if (pos)
114 *pos = -1;
115 map = (uchar *)calloc(1, config->key_count);
116 if (!map) {
117 debug("%s: failed to malloc %d bytes\n", __func__,
118 config->key_count);
119 return NULL;
120 }
121
122 for (; len >= sizeof(u32); data++, len -= 4) {
123 u32 tmp = fdt32_to_cpu(*data);
124 int key_code, row, col;
125 int entry;
126
127 row = (tmp >> 24) & 0xff;
128 col = (tmp >> 16) & 0xff;
129 key_code = tmp & 0xffff;
130 entry = row * config->num_cols + col;
131 map[entry] = key_code;
132 debug(" map %d, %d: pos=%d, keycode=%d\n", row, col,
133 entry, key_code);
134 if (pos && map_keycode == key_code)
135 *pos = entry;
136 }
137
138 return map;
139 }
140
key_matrix_decode_fdt(struct udevice * dev,struct key_matrix * config)141 int key_matrix_decode_fdt(struct udevice *dev, struct key_matrix *config)
142 {
143 const u32 *prop;
144 int proplen;
145 uchar *plain_keycode;
146
147 prop = dev_read_prop(dev, "linux,keymap", &proplen);
148 /* Basic keymap is required */
149 if (!prop) {
150 debug("%s: cannot find keycode-plain map\n", __func__);
151 return -1;
152 }
153
154 plain_keycode = create_keymap(config, prop, proplen, KEY_FN,
155 &config->fn_pos);
156 config->plain_keycode = plain_keycode;
157 /* Conversion error -> fail */
158 if (!config->plain_keycode)
159 return -1;
160
161 prop = dev_read_prop(dev, "linux,fn-keymap", &proplen);
162 /* fn keymap is optional */
163 if (!prop)
164 goto done;
165
166 config->fn_keycode = create_keymap(config, prop, proplen, -1, NULL);
167 /* Conversion error -> fail */
168 if (!config->fn_keycode) {
169 free(plain_keycode);
170 return -1;
171 }
172
173 done:
174 debug("%s: Decoded key maps %p, %p from fdt\n", __func__,
175 config->plain_keycode, config->fn_keycode);
176 return 0;
177 }
178
key_matrix_init(struct key_matrix * config,int rows,int cols,int ghost_filter)179 int key_matrix_init(struct key_matrix *config, int rows, int cols,
180 int ghost_filter)
181 {
182 memset(config, '\0', sizeof(*config));
183 config->num_rows = rows;
184 config->num_cols = cols;
185 config->key_count = rows * cols;
186 config->ghost_filter = ghost_filter;
187 assert(config->key_count > 0);
188
189 return 0;
190 }
191