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