include/key_matrix.h

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