From: Bernie Thompson bhthompson@chromium.org
Matrix keyboards require a key map to be set up, and must also deal with key ghosting.
Create a keyboard matrix management implementation which can be leveraged by various keyboard drivers. This includes code to read the keymap from the FDT and perform debouncing.
Signed-off-by: Bernie Thompson bhthompson@chromium.org Signed-off-by: Simon Glass sjg@chromium.org --- Changes in v4: - Move matrix keyboard handling into a separate module
drivers/input/Makefile | 1 + drivers/input/key_matrix.c | 208 ++++++++++++++++++++++++++++++++++++++++++++ include/key_matrix.h | 99 +++++++++++++++++++++ 3 files changed, 308 insertions(+), 0 deletions(-) create mode 100644 drivers/input/key_matrix.c create mode 100644 include/key_matrix.h
diff --git a/drivers/input/Makefile b/drivers/input/Makefile index d06acb9..b8d8623 100644 --- a/drivers/input/Makefile +++ b/drivers/input/Makefile @@ -31,6 +31,7 @@ COBJS-y += keyboard.o pc_keyb.o COBJS-$(CONFIG_PS2MULT) += ps2mult.o ps2ser.o endif COBJS-y += input.o +COBJS-y += key_matrix.o
COBJS := $(COBJS-y) SRCS := $(COBJS:.o=.c) diff --git a/drivers/input/key_matrix.c b/drivers/input/key_matrix.c new file mode 100644 index 0000000..84b898f --- /dev/null +++ b/drivers/input/key_matrix.c @@ -0,0 +1,208 @@ +/* + * Manage Keyboard Matrices + * + * Copyright (c) 2012 The Chromium OS Authors. + * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <fdtdec.h> +#include <key_matrix.h> +#include <malloc.h> +#include <linux/input.h> + +/** + * Determine if the current keypress configuration can cause key ghosting + * + * We figure this out by seeing if we have two or more keys in the same + * column, as well as two or more keys in the same row. + * + * @param config Keyboard matrix config + * @param keys List of keys to check + * @param valid Number of valid keypresses to check + * @return 0 if no ghosting is possible, 1 if it is + */ +static int has_ghosting(struct key_matrix *config, struct key_matrix_key *keys, + int valid) +{ + int key_in_same_col = 0, key_in_same_row = 0; + int i, j; + + for (i = 0; i < valid; i++) { + /* + * Find 2 keys such that one key is in the same row + * and the other is in the same column as the i-th key. + */ + for (j = i + 1; j < valid; j++) { + if (keys[j].col == keys[i].col) + key_in_same_col = 1; + if (keys[j].row == keys[i].row) + key_in_same_row = 1; + } + } + + if (key_in_same_col && key_in_same_row) + return 1; + else + return 0; +} + +int key_matrix_decode(struct key_matrix *config, struct key_matrix_key keys[], + int num_keys, int keycode[], int max_keycodes) +{ + const u8 *keymap; + int valid, upto; + int pos; + + debug("%s: num_keys = %d\n", __func__, num_keys); + keymap = config->plain_keycode; + for (valid = upto = 0; upto < num_keys; upto++) { + struct key_matrix_key *key = &keys[upto]; + + debug(" valid=%d, row=%d, col=%d\n", key->valid, key->row, + key->col); + if (!key->valid) + continue; + pos = key->row * config->num_cols + key->col; + if (config->fn_keycode && pos == config->fn_pos) + keymap = config->fn_keycode; + + /* Convert the (row, col) values into a keycode */ + if (valid < max_keycodes) + keycode[valid++] = keymap[pos]; + debug(" keycode=%d\n", keymap[pos]); + } + + /* For a ghost key config, ignore the keypresses for this iteration. */ + if (valid >= 3 && has_ghosting(config, keys, valid)) { + valid = 0; + debug(" ghosting detected!\n"); + } + debug(" %d valid keycodes found\n", valid); + + return valid; +} + +/** + * Create a new keycode map from some provided data + * + * This decodes a keycode map in the format used by the fdt, which is one + * word per entry, with the row, col and keycode encoded in that word. + * + * We create a (row x col) size byte array with each entry containing the + * keycode for that (row, col). We also search for map_keycode and return + * its position if found (this is used for finding the Fn key). + * + * @param config Key matrix dimensions structure + * @param data Keycode data + * @param len Number of entries in keycode table + * @param map_keycode Key code to find in the map + * @param pos Returns position of map_keycode, if found, else -1 + * @return map Pointer to allocated map + */ +static uchar *create_keymap(struct key_matrix *config, u32 *data, int len, + int map_keycode, int *pos) +{ + uchar *map; + + if (pos) + *pos = -1; + map = (uchar *)calloc(1, config->key_count); + if (!map) { + debug("%s: failed to malloc %d bytes\n", __func__, + config->key_count); + return NULL; + } + + for (; len >= sizeof(u32); data++, len -= 4) { + u32 tmp = fdt32_to_cpu(*data); + int key_code, row, col; + int entry; + + row = (tmp >> 24) & 0xff; + col = (tmp >> 16) & 0xff; + key_code = tmp & 0xffff; + entry = row * config->num_cols + col; + map[entry] = key_code; + if (pos && map_keycode == key_code) + *pos = entry; + } + + return map; +} + +int key_matrix_decode_fdt(struct key_matrix *config, const void *blob, + int node) +{ + const struct fdt_property *prop; + int offset; + + /* Check each property name for ones that we understand */ + for (offset = fdt_first_property_offset(blob, node); + offset > 0; + offset = fdt_next_property_offset(blob, offset)) { + const char *name; + int len; + + prop = fdt_get_property_by_offset(blob, offset, NULL); + name = fdt_string(blob, fdt32_to_cpu(prop->nameoff)); + len = strlen(name); + + /* Name needs to match "1,<type>keymap" */ + debug("%s: property '%s'\n", __func__, name); + if (strncmp(name, "1,", 2) || len < 8 || + strcmp(name + len - 6, "keymap")) + continue; + + len -= 8; + if (len == 0) { + config->plain_keycode = create_keymap(config, + (u32 *)prop->data, fdt32_to_cpu(prop->len), + KEY_FN, &config->fn_pos); + } else if (0 == strncmp(name + 2, "fn-", len)) { + config->fn_keycode = create_keymap(config, + (u32 *)prop->data, fdt32_to_cpu(prop->len), + -1, NULL); + } else { + debug("%s: unrecognised property '%s'\n", __func__, + name); + } + } + debug("%s: Decoded key maps %p, %p from fdt\n", __func__, + config->plain_keycode, config->fn_keycode); + + if (!config->plain_keycode) { + debug("%s: cannot find keycode-plain map\n", __func__); + return -1; + } + + return 0; +} + +int key_matrix_init(struct key_matrix *config, int rows, int cols) +{ + memset(config, '\0', sizeof(*config)); + config->num_rows = rows; + config->num_cols = cols; + config->key_count = rows * cols; + assert(config->key_count > 0); + + return 0; +} diff --git a/include/key_matrix.h b/include/key_matrix.h new file mode 100644 index 0000000..f413314 --- /dev/null +++ b/include/key_matrix.h @@ -0,0 +1,99 @@ +/* + * Keyboard matrix helper functions + * + * Copyright (c) 2012 The Chromium OS Authors. + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#ifndef _KEY_MATRIX_H +#define _KEY_MATRIX_H + +#include <common.h> + +/* Information about a matrix keyboard */ +struct key_matrix { + /* Dimensions of the keyboard matrix, in rows and columns */ + int num_rows; + int num_cols; + int key_count; /* number of keys in the matrix (= rows * cols) */ + + /* + * Information about keycode mappings. The plain_keycode array must + * exist but fn may be NULL in which case it is not decoded. + */ + const u8 *plain_keycode; /* key code for each row / column */ + const u8 *fn_keycode; /* ...when Fn held down */ + int fn_pos; /* position of Fn key in key (or -1) */ +}; + +/* Information about a particular key (row, column pair) in the matrix */ +struct key_matrix_key { + uint8_t row; /* row number (0 = first) */ + uint8_t col; /* column number (0 = first) */ + uint8_t valid; /* 1 if valid, 0 to ignore this */ +}; + +/** + * Decode a set of pressed keys into key codes + * + * Given a list of keys that are pressed, this converts this list into + * a list of key codes. Each of the keys has a valid flag, which can be + * used to mark a particular key as invalid (so that it is ignored). + * + * The plain keymap is used, unless the Fn key is detected along the way, + * at which point we switch to the Fn key map. + * + * If key ghosting is detected, we simply ignore the keys and return 0. + * + * @param config Keyboard matrix config + * @param keys List of keys to process (each is row, col) + * @param num_keys Number of keys to process + * @param keycode Returns a list of key codes, decoded from input + * @param max_keycodes Size of key codes array (suggest 8) + * + */ +int key_matrix_decode(struct key_matrix *config, struct key_matrix_key *keys, + int num_keys, int keycode[], int max_keycodes); + +/** + * Read the keyboard configuration out of the fdt. + * + * Decode properties of named "linux,<type>keymap" where <type> is either + * empty, or "fn-". Then set up the plain key map (and the FN keymap if + * present). + * + * @param config Keyboard matrix config + * @param blob FDT blob + * @param node Node containing compatible data + * @return 0 if ok, -1 on error + */ +int key_matrix_decode_fdt(struct key_matrix *config, const void *blob, + int node); + +/** + * Set up a new key matrix. + * + * @param config Keyboard matrix config + * @param rows Number of rows in key matrix + * @param cols Number of columns in key matrix + * @return 0 if ok, -1 on error + */ +int key_matrix_init(struct key_matrix *config, int rows, int cols); + +#endif