input: Add support for keyboard matrix decoding from an fdt
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> Signed-off-by: Tom Warren <twarren@nvidia.com>
This commit is contained in:
Bernie Thompson
Albert ARIBAUD
parent
9bc590e511
commit
92c27c5193
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@ -26,11 +26,13 @@ include $(TOPDIR)/config.mk
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LIB := $(obj)libinput.o
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COBJS-$(CONFIG_I8042_KBD) += i8042.o
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COBJS-$(CONFIG_TEGRA2_KEYBOARD) += tegra-kbc.o
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ifdef CONFIG_PS2KBD
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COBJS-y += keyboard.o pc_keyb.o
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COBJS-$(CONFIG_PS2MULT) += ps2mult.o ps2ser.o
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endif
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COBJS-y += input.o
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COBJS-$(CONFIG_OF_CONTROL) += key_matrix.o
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COBJS := $(COBJS-y)
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SRCS := $(COBJS:.o=.c)
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@ -0,0 +1,208 @@
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/*
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* Manage Keyboard Matrices
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*
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* Copyright (c) 2012 The Chromium OS Authors.
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* (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <fdtdec.h>
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#include <key_matrix.h>
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#include <malloc.h>
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#include <linux/input.h>
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/**
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* Determine if the current keypress configuration can cause key ghosting
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*
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* We figure this out by seeing if we have two or more keys in the same
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* column, as well as two or more keys in the same row.
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*
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* @param config Keyboard matrix config
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* @param keys List of keys to check
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* @param valid Number of valid keypresses to check
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* @return 0 if no ghosting is possible, 1 if it is
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*/
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static int has_ghosting(struct key_matrix *config, struct key_matrix_key *keys,
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int valid)
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{
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int key_in_same_col = 0, key_in_same_row = 0;
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int i, j;
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for (i = 0; i < valid; i++) {
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/*
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* Find 2 keys such that one key is in the same row
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* and the other is in the same column as the i-th key.
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*/
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for (j = i + 1; j < valid; j++) {
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if (keys[j].col == keys[i].col)
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key_in_same_col = 1;
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if (keys[j].row == keys[i].row)
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key_in_same_row = 1;
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}
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}
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if (key_in_same_col && key_in_same_row)
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return 1;
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else
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return 0;
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}
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int key_matrix_decode(struct key_matrix *config, struct key_matrix_key keys[],
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int num_keys, int keycode[], int max_keycodes)
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{
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const u8 *keymap;
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int valid, upto;
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int pos;
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debug("%s: num_keys = %d\n", __func__, num_keys);
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keymap = config->plain_keycode;
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for (valid = upto = 0; upto < num_keys; upto++) {
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struct key_matrix_key *key = &keys[upto];
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debug(" valid=%d, row=%d, col=%d\n", key->valid, key->row,
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key->col);
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if (!key->valid)
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continue;
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pos = key->row * config->num_cols + key->col;
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if (config->fn_keycode && pos == config->fn_pos)
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keymap = config->fn_keycode;
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/* Convert the (row, col) values into a keycode */
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if (valid < max_keycodes)
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keycode[valid++] = keymap[pos];
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debug(" keycode=%d\n", keymap[pos]);
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}
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/* For a ghost key config, ignore the keypresses for this iteration. */
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if (valid >= 3 && has_ghosting(config, keys, valid)) {
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valid = 0;
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debug(" ghosting detected!\n");
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}
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debug(" %d valid keycodes found\n", valid);
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return valid;
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}
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/**
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* Create a new keycode map from some provided data
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*
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* This decodes a keycode map in the format used by the fdt, which is one
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* word per entry, with the row, col and keycode encoded in that word.
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*
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* We create a (row x col) size byte array with each entry containing the
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* keycode for that (row, col). We also search for map_keycode and return
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* its position if found (this is used for finding the Fn key).
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*
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* @param config Key matrix dimensions structure
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* @param data Keycode data
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* @param len Number of entries in keycode table
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* @param map_keycode Key code to find in the map
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* @param pos Returns position of map_keycode, if found, else -1
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* @return map Pointer to allocated map
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*/
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static uchar *create_keymap(struct key_matrix *config, u32 *data, int len,
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int map_keycode, int *pos)
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{
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uchar *map;
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if (pos)
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*pos = -1;
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map = (uchar *)calloc(1, config->key_count);
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if (!map) {
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debug("%s: failed to malloc %d bytes\n", __func__,
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config->key_count);
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return NULL;
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}
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for (; len >= sizeof(u32); data++, len -= 4) {
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u32 tmp = fdt32_to_cpu(*data);
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int key_code, row, col;
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int entry;
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row = (tmp >> 24) & 0xff;
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col = (tmp >> 16) & 0xff;
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key_code = tmp & 0xffff;
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entry = row * config->num_cols + col;
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map[entry] = key_code;
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if (pos && map_keycode == key_code)
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*pos = entry;
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}
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return map;
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}
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int key_matrix_decode_fdt(struct key_matrix *config, const void *blob,
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int node)
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{
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const struct fdt_property *prop;
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int offset;
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/* Check each property name for ones that we understand */
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for (offset = fdt_first_property_offset(blob, node);
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offset > 0;
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offset = fdt_next_property_offset(blob, offset)) {
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const char *name;
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int len;
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prop = fdt_get_property_by_offset(blob, offset, NULL);
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name = fdt_string(blob, fdt32_to_cpu(prop->nameoff));
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len = strlen(name);
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/* Name needs to match "1,<type>keymap" */
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debug("%s: property '%s'\n", __func__, name);
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if (strncmp(name, "1,", 2) || len < 8 ||
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strcmp(name + len - 6, "keymap"))
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continue;
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len -= 8;
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if (len == 0) {
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config->plain_keycode = create_keymap(config,
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(u32 *)prop->data, fdt32_to_cpu(prop->len),
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KEY_FN, &config->fn_pos);
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} else if (0 == strncmp(name + 2, "fn-", len)) {
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config->fn_keycode = create_keymap(config,
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(u32 *)prop->data, fdt32_to_cpu(prop->len),
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-1, NULL);
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} else {
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debug("%s: unrecognised property '%s'\n", __func__,
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name);
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}
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}
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debug("%s: Decoded key maps %p, %p from fdt\n", __func__,
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config->plain_keycode, config->fn_keycode);
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if (!config->plain_keycode) {
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debug("%s: cannot find keycode-plain map\n", __func__);
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return -1;
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}
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return 0;
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}
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int key_matrix_init(struct key_matrix *config, int rows, int cols)
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{
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memset(config, '\0', sizeof(*config));
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config->num_rows = rows;
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config->num_cols = cols;
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config->key_count = rows * cols;
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assert(config->key_count > 0);
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return 0;
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}
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@ -0,0 +1,99 @@
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/*
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* Keyboard matrix helper functions
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*
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* Copyright (c) 2012 The Chromium OS Authors.
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#ifndef _KEY_MATRIX_H
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#define _KEY_MATRIX_H
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#include <common.h>
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/* Information about a matrix keyboard */
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struct key_matrix {
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/* Dimensions of the keyboard matrix, in rows and columns */
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int num_rows;
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int num_cols;
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int key_count; /* number of keys in the matrix (= rows * cols) */
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/*
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* Information about keycode mappings. The plain_keycode array must
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* exist but fn may be NULL in which case it is not decoded.
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*/
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const u8 *plain_keycode; /* key code for each row / column */
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const u8 *fn_keycode; /* ...when Fn held down */
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int fn_pos; /* position of Fn key in key (or -1) */
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};
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/* Information about a particular key (row, column pair) in the matrix */
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struct key_matrix_key {
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uint8_t row; /* row number (0 = first) */
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uint8_t col; /* column number (0 = first) */
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uint8_t valid; /* 1 if valid, 0 to ignore this */
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};
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/**
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* Decode a set of pressed keys into key codes
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*
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* Given a list of keys that are pressed, this converts this list into
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* a list of key codes. Each of the keys has a valid flag, which can be
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* used to mark a particular key as invalid (so that it is ignored).
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*
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* The plain keymap is used, unless the Fn key is detected along the way,
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* at which point we switch to the Fn key map.
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*
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* If key ghosting is detected, we simply ignore the keys and return 0.
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*
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* @param config Keyboard matrix config
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* @param keys List of keys to process (each is row, col)
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* @param num_keys Number of keys to process
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* @param keycode Returns a list of key codes, decoded from input
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* @param max_keycodes Size of key codes array (suggest 8)
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*
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*/
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int key_matrix_decode(struct key_matrix *config, struct key_matrix_key *keys,
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int num_keys, int keycode[], int max_keycodes);
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/**
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* Read the keyboard configuration out of the fdt.
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*
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* Decode properties of named "linux,<type>keymap" where <type> is either
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* empty, or "fn-". Then set up the plain key map (and the FN keymap if
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* present).
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*
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* @param config Keyboard matrix config
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* @param blob FDT blob
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* @param node Node containing compatible data
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* @return 0 if ok, -1 on error
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*/
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int key_matrix_decode_fdt(struct key_matrix *config, const void *blob,
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int node);
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/**
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* Set up a new key matrix.
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*
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* @param config Keyboard matrix config
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* @param rows Number of rows in key matrix
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* @param cols Number of columns in key matrix
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* @return 0 if ok, -1 on error
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*/
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int key_matrix_init(struct key_matrix *config, int rows, int cols);
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#endif
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