include/key_matrix.h

   1 /*
   2  * Keyboard matrix helper functions
   3  *
   4  * Copyright (c) 2012 The Chromium OS Authors.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #ifndef _KEY_MATRIX_H
  10 #define _KEY_MATRIX_H
  11
  12 #include <common.h>
  13
  14 /* Information about a matrix keyboard */
  15 struct key_matrix {
  16         /* Dimensions of the keyboard matrix, in rows and columns */
  17         int num_rows;
  18         int num_cols;
  19         int key_count;  /* number of keys in the matrix (= rows * cols) */
  20
  21         /*
  22          * Information about keycode mappings. The plain_keycode array must
  23          * exist but fn may be NULL in which case it is not decoded.
  24          */
  25         const u8 *plain_keycode;        /* key code for each row / column */
  26         const u8 *fn_keycode;           /* ...when Fn held down */
  27         int fn_pos;                     /* position of Fn key in key (or -1) */
  28         int ghost_filter;               /* non-zero to enable ghost filter */
  29 };
  30
  31 /* Information about a particular key (row, column pair) in the matrix */
  32 struct key_matrix_key {
  33         uint8_t row;    /* row number (0 = first) */
  34         uint8_t col;    /* column number (0 = first) */
  35         uint8_t valid;  /* 1 if valid, 0 to ignore this */
  36 };
  37
  38 /**
  39  * Decode a set of pressed keys into key codes
  40  *
  41  * Given a list of keys that are pressed, this converts this list into
  42  * a list of key codes. Each of the keys has a valid flag, which can be
  43  * used to mark a particular key as invalid (so that it is ignored).
  44  *
  45  * The plain keymap is used, unless the Fn key is detected along the way,
  46  * at which point we switch to the Fn key map.
  47  *
  48  * If key ghosting is detected, we simply ignore the keys and return 0.
  49  *
  50  * @param config        Keyboard matrix config
  51  * @param keys          List of keys to process (each is row, col)
  52  * @param num_keys      Number of keys to process
  53  * @param keycode       Returns a list of key codes, decoded from input
  54  * @param max_keycodes  Size of key codes array (suggest 8)
  55  *
  56  */
  57 int key_matrix_decode(struct key_matrix *config, struct key_matrix_key *keys,
  58                       int num_keys, int keycode[], int max_keycodes);
  59
  60 /**
  61  * Read the keyboard configuration out of the fdt.
  62  *
  63  * Decode properties of named "linux,<type>keymap" where <type> is either
  64  * empty, or "fn-". Then set up the plain key map (and the FN keymap if
  65  * present).
  66  *
  67  * @param config        Keyboard matrix config
  68  * @param blob          FDT blob
  69  * @param node          Node containing compatible data
  70  * @return 0 if ok, -1 on error
  71  */
  72 int key_matrix_decode_fdt(struct udevice *dev, struct key_matrix *config);
  73
  74 /**
  75  * Set up a new key matrix.
  76  *
  77  * @param config        Keyboard matrix config
  78  * @param rows          Number of rows in key matrix
  79  * @param cols          Number of columns in key matrix
  80  * @param ghost_filter  Non-zero to enable ghost filtering
  81  * @return 0 if ok, -1 on error
  82  */
  83 int key_matrix_init(struct key_matrix *config, int rows, int cols,
  84                     int ghost_filter);
  85
  86 #endif