/*
 * Keyboard input helper functions (too small to be called a layer)
 *
 * Copyright (c) 2011 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#ifndef _INPUT_H
#define _INPUT_H

enum {
        INPUT_MAX_MODIFIERS     = 4,
        INPUT_BUFFER_LEN        = 16,
};

enum {
        /* Keyboard LEDs */
        INPUT_LED_SCROLL        = 1 << 0,
        INPUT_LED_NUM           = 1 << 1,
        INPUT_LED_CAPS          = 1 << 2,
};

/*
 * This table translates key codes to ASCII. Most of the entries are ASCII
 * codes, but entries after KEY_FIRST_MOD indicate that this key is a
 * modifier key, like shift, ctrl. KEY_FIRST_MOD + MOD_SHIFT is the shift
 * key, for example.
 */
struct input_key_xlate {
        /* keycode of the modifiers which select this table, -1 if none */
        int left_keycode;
        int right_keycode;
        const uchar *xlate;     /* keycode to ASCII table */
        int num_entries;        /* number of entries in this table */
};

struct input_config {
        struct udevice *dev;
        uchar fifo[INPUT_BUFFER_LEN];
        int fifo_in, fifo_out;

        /* Which modifiers are active (1 bit for each MOD_... value) */
        uchar modifiers;
        uchar flags;            /* active state keys (FLAGS_...) */
        uchar leds;             /* active LEDs (INPUT_LED_...) */
        uchar leds_changed;     /* LEDs that just changed */
        uchar num_tables;       /* number of modifier tables */
        int prev_keycodes[INPUT_BUFFER_LEN];    /* keys held last time */
        int num_prev_keycodes;  /* number of prev keys */
        struct input_key_xlate table[INPUT_MAX_MODIFIERS];

        /**
         * Function the input helper calls to scan the keyboard
         *
         * @param config        Input state
         * @return 0 if no keys read, otherwise number of keys read, or 1 if
         *              unknown
         */
        int (*read_keys)(struct input_config *config);
        bool allow_repeats;             /* Don't filter out repeats */
        unsigned int next_repeat_ms;    /* Next time we repeat a key */
        unsigned int repeat_delay_ms;   /* Time before autorepeat starts */
        unsigned int repeat_rate_ms;    /* Autorepeat rate in ms */
};

struct stdio_dev;

/**
 * Convert a list of key codes into ASCII and send them
 *
 * @param config        Input state
 * @param keycode       List of key codes to examine
 * @param num_keycodes  Number of key codes
 * @return number of ascii characters sent, or 0 if none, or -1 for an
 *      internal error
 */
int input_send_keycodes(struct input_config *config, int keycode[], int count);

/**
 * Add a new keycode to an existing list of keycodes
 *
 * This can be used to handle keyboards which do their own scanning. An
 * internal list of depressed keys is maintained by the input library. Then
 * this function is called to add a new key to the list (when a 'make code' is
 * received), or remove a key (when a 'break code' is received).
 *
 * This function looks after maintenance of the list of active keys, and calls
 * input_send_keycodes() with its updated list.
 *
 * @param config        Input state
 * @param new_keycode   New keycode to add/remove
 * @param release       true if this key was released, false if depressed
 * @return number of ascii characters sent, or 0 if none, or -1 for an
 *      internal error
 */
int input_add_keycode(struct input_config *config, int new_keycode,
                      bool release);

/**
 * Add a new key translation table to the input
 *
 * @param config        Input state
 * @param left_keycode  Key to hold to get into this table
 * @param right_keycode Another key to hold to get into this table
 * @param xlate         Conversion table from key codes to ASCII
 * @param num_entries   Number of entries in xlate table
 */
int input_add_table(struct input_config *config, int left_keycode,
                    int right_keycode, const uchar *xlate, int num_entries);

/**
 * Test if keys are available to be read
 *
 * @param config        Input state
 * @return 0 if no keys available, 1 if keys are available
 */
int input_tstc(struct input_config *config);

/**
 * Read a key
 *
 * TODO: U-Boot wants 0 for no key, but Ctrl-@ is a valid key...
 *
 * @param config        Input state
 * @return key, or 0 if no key, or -1 if error
 */
int input_getc(struct input_config *config);

/**
 * Register a new device with stdio and switch to it if wanted
 *
 * @param dev   Pointer to device
 * @return 0 if ok, -1 on error
 */
int input_stdio_register(struct stdio_dev *dev);

/**
 * Set up the keyboard autorepeat delays
 *
 * @param repeat_delay_ms       Delay before key auto-repeat starts (in ms)
 * @param repeat_rate_ms        Delay between successive key repeats (in ms)
 */
void input_set_delays(struct input_config *config, int repeat_delay_ms,
               int repeat_rate_ms);

/**
 * Tell the input layer whether to allow the caller to determine repeats
 *
 * Generally the input library handles processing of a list of scanned keys.
 * Repeated keys need to be generated based on a timer in this case, since all
 * that is provided is a list of keys current depressed.
 *
 * Keyboards which do their own scanning will resend codes when they want to
 * inject a repeating key. This function can be called at start-up to select
 * this behaviour.
 *
 * @param config        Input state
 * @param allow_repeats true to repeat depressed keys every time
 *                      input_send_keycodes() is called, false to do normal
 *                      keyboard repeat processing with a timer.
 */
void input_allow_repeats(struct input_config *config, bool allow_repeats);

/**
 * Check if keyboard LEDs need to be updated
 *
 * This can be called after input_tstc() to see if keyboard LEDs need
 * updating.
 *
 * @param config        Input state
 * @return -1 if no LEDs need updating, other value if they do
 */
int input_leds_changed(struct input_config *config);

/**
 * Set up the key map tables
 *
 * This must be called after input_init() or keycode decoding will not work.
 *
 * @param config        Input state
 * @param german        true to use German keyboard layout, false for US
 * @return 0 if ok, -1 on error
 */
int input_add_tables(struct input_config *config, bool german);

/**
 * Set up the input handler with basic key maps.
 *
 * @param config        Input state
 * @param leds          Initial LED value (INPUT_LED_ mask), 0 suggested
 * @return 0 if ok, -1 on error
 */
int input_init(struct input_config *config, int leds);

#ifdef CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
extern int overwrite_console(void);
#define OVERWRITE_CONSOLE overwrite_console()
#else
#define OVERWRITE_CONSOLE 0
#endif /* CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE */

#endif