--- /dev/null
+/*
+ * Manage Keyboard Matrices
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#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;
+
+ if (!config->ghost_filter || valid < 3)
+ return 0;
+
+ 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 (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;
+ debug(" map %d, %d: pos=%d, keycode=%d\n", row, col,
+ 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 proplen;
+ uchar *plain_keycode;
+
+ prop = fdt_get_property(blob, node, "linux,keymap", &proplen);
+ /* Basic keymap is required */
+ if (!prop) {
+ debug("%s: cannot find keycode-plain map\n", __func__);
+ return -1;
+ }
+
+ plain_keycode = create_keymap(config, (u32 *)prop->data,
+ proplen, KEY_FN, &config->fn_pos);
+ config->plain_keycode = plain_keycode;
+ /* Conversion error -> fail */
+ if (!config->plain_keycode)
+ return -1;
+
+ prop = fdt_get_property(blob, node, "linux,fn-keymap", &proplen);
+ /* fn keymap is optional */
+ if (!prop)
+ goto done;
+
+ config->fn_keycode = create_keymap(config, (u32 *)prop->data,
+ proplen, -1, NULL);
+ /* Conversion error -> fail */
+ if (!config->fn_keycode) {
+ free(plain_keycode);
+ return -1;
+ }
+
+done:
+ debug("%s: Decoded key maps %p, %p from fdt\n", __func__,
+ config->plain_keycode, config->fn_keycode);
+ return 0;
+}
+
+int key_matrix_init(struct key_matrix *config, int rows, int cols,
+ int ghost_filter)
+{
+ memset(config, '\0', sizeof(*config));
+ config->num_rows = rows;
+ config->num_cols = cols;
+ config->key_count = rows * cols;
+ config->ghost_filter = ghost_filter;
+ assert(config->key_count > 0);
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff