include/key_matrix.h

   1 /*
   2  * Keyboard matrix helper functions
   3  *
   4  * Copyright (c) 2012 The Chromium OS Authors.
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #ifndef _KEY_MATRIX_H
  25 #define _KEY_MATRIX_H
  26
  27 #include <common.h>
  28
  29 /* Information about a matrix keyboard */
  30 struct key_matrix {
  31         /* Dimensions of the keyboard matrix, in rows and columns */
  32         int num_rows;
  33         int num_cols;
  34         int key_count;  /* number of keys in the matrix (= rows * cols) */
  35
  36         /*
  37          * Information about keycode mappings. The plain_keycode array must
  38          * exist but fn may be NULL in which case it is not decoded.
  39          */
  40         const u8 *plain_keycode;        /* key code for each row / column */
  41         const u8 *fn_keycode;           /* ...when Fn held down */
  42         int fn_pos;                     /* position of Fn key in key (or -1) */
  43         int ghost_filter;               /* non-zero to enable ghost filter */
  44 };
  45
  46 /* Information about a particular key (row, column pair) in the matrix */
  47 struct key_matrix_key {
  48         uint8_t row;    /* row number (0 = first) */
  49         uint8_t col;    /* column number (0 = first) */
  50         uint8_t valid;  /* 1 if valid, 0 to ignore this */
  51 };
  52
  53 /**
  54  * Decode a set of pressed keys into key codes
  55  *
  56  * Given a list of keys that are pressed, this converts this list into
  57  * a list of key codes. Each of the keys has a valid flag, which can be
  58  * used to mark a particular key as invalid (so that it is ignored).
  59  *
  60  * The plain keymap is used, unless the Fn key is detected along the way,
  61  * at which point we switch to the Fn key map.
  62  *
  63  * If key ghosting is detected, we simply ignore the keys and return 0.
  64  *
  65  * @param config        Keyboard matrix config
  66  * @param keys          List of keys to process (each is row, col)
  67  * @param num_keys      Number of keys to process
  68  * @param keycode       Returns a list of key codes, decoded from input
  69  * @param max_keycodes  Size of key codes array (suggest 8)
  70  *
  71  */
  72 int key_matrix_decode(struct key_matrix *config, struct key_matrix_key *keys,
  73                       int num_keys, int keycode[], int max_keycodes);
  74
  75 /**
  76  * Read the keyboard configuration out of the fdt.
  77  *
  78  * Decode properties of named "linux,<type>keymap" where <type> is either
  79  * empty, or "fn-". Then set up the plain key map (and the FN keymap if
  80  * present).
  81  *
  82  * @param config        Keyboard matrix config
  83  * @param blob          FDT blob
  84  * @param node          Node containing compatible data
  85  * @return 0 if ok, -1 on error
  86  */
  87 int key_matrix_decode_fdt(struct key_matrix *config, const void *blob,
  88                           int node);
  89
  90 /**
  91  * Set up a new key matrix.
  92  *
  93  * @param config        Keyboard matrix config
  94  * @param rows          Number of rows in key matrix
  95  * @param cols          Number of columns in key matrix
  96  * @param ghost_filter  Non-zero to enable ghost filtering
  97  * @return 0 if ok, -1 on error
  98  */
  99 int key_matrix_init(struct key_matrix *config, int rows, int cols,
 100                     int ghost_filter);
 101
 102 #endif