/*
 *  (C) Copyright 2011
 *  NVIDIA Corporation <www.nvidia.com>
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <fdtdec.h>
#include <input.h>
#include <key_matrix.h>
#include <stdio_dev.h>
#include <tegra-kbc.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/funcmux.h>
#include <asm/arch-tegra/timer.h>
#include <linux/input.h>

DECLARE_GLOBAL_DATA_PTR;

enum {
        KBC_MAX_GPIO            = 24,
        KBC_MAX_KPENT           = 8,    /* size of keypress entry queue */
};

#define KBC_FIFO_TH_CNT_SHIFT           14
#define KBC_DEBOUNCE_CNT_SHIFT          4
#define KBC_CONTROL_FIFO_CNT_INT_EN     (1 << 3)
#define KBC_CONTROL_KBC_EN              (1 << 0)
#define KBC_INT_FIFO_CNT_INT_STATUS     (1 << 2)
#define KBC_KPENT_VALID                 (1 << 7)
#define KBC_ST_STATUS                   (1 << 3)

enum {
        KBC_DEBOUNCE_COUNT      = 2,
        KBC_REPEAT_RATE_MS      = 30,
        KBC_REPEAT_DELAY_MS     = 240,
        KBC_CLOCK_KHZ           = 32,   /* Keyboard uses a 32KHz clock */
};

/* keyboard controller config and state */
static struct keyb {
        struct input_config input;      /* The input layer */
        struct key_matrix matrix;       /* The key matrix layer */

        struct kbc_tegra *kbc;          /* tegra keyboard controller */
        unsigned char inited;           /* 1 if keyboard has been inited */
        unsigned char first_scan;       /* 1 if this is our first key scan */
        unsigned char created;          /* 1 if driver has been created */

        /*
         * After init we must wait a short time before polling the keyboard.
         * This gives the tegra keyboard controller time to react after reset
         * and lets us grab keys pressed during reset.
         */
        unsigned int init_dly_ms;       /* Delay before we can read keyboard */
        unsigned int start_time_ms;     /* Time that we inited (in ms) */
        unsigned int last_poll_ms;      /* Time we should last polled */
        unsigned int next_repeat_ms;    /* Next time we repeat a key */
} config;

/**
 * reads the keyboard fifo for current keypresses
 *
 * @param config        Keyboard config
 * @param fifo          Place to put fifo results
 * @param max_keycodes  Maximum number of key codes to put in the fifo
 * @return number of items put into fifo
 */
static int tegra_kbc_find_keys(struct keyb *config, int *fifo,
                               int max_keycodes)
{
        struct key_matrix_key keys[KBC_MAX_KPENT], *key;
        u32 kp_ent = 0;
        int i;

        for (key = keys, i = 0; i < KBC_MAX_KPENT; i++, key++) {
                /* Get next word */
                if (!(i & 3))
                        kp_ent = readl(&config->kbc->kp_ent[i / 4]);

                key->valid = (kp_ent & KBC_KPENT_VALID) != 0;
                key->row = (kp_ent >> 3) & 0xf;
                key->col = kp_ent & 0x7;

                /* Shift to get next entry */
                kp_ent >>= 8;
        }
        return key_matrix_decode(&config->matrix, keys, KBC_MAX_KPENT, fifo,
                                 max_keycodes);
}

/**
 * Process all the keypress sequences in fifo and send key codes
 *
 * The fifo contains zero or more keypress sets. Each set
 * consists of from 1-8 keycodes, representing the keycodes which
 * were simultaneously pressed during that scan.
 *
 * This function works through each set and generates ASCII characters
 * for each. Not that one set may produce more than one ASCII characters -
 * for example holding down 'd' and 'f' at the same time will generate
 * two ASCII characters.
 *
 * Note: if fifo_cnt is 0, we will tell the input layer that no keys are
 * pressed.
 *
 * @param config        Keyboard config
 * @param fifo_cnt      Number of entries in the keyboard fifo
 */
static void process_fifo(struct keyb *config, int fifo_cnt)
{
        int fifo[KBC_MAX_KPENT];
        int cnt = 0;

        /* Always call input_send_keycodes() at least once */
        do {
                if (fifo_cnt)
                        cnt = tegra_kbc_find_keys(config, fifo, KBC_MAX_KPENT);

                input_send_keycodes(&config->input, fifo, cnt);
        } while (--fifo_cnt > 0);
}

/**
 * Check the keyboard controller and emit ASCII characters for any keys that
 * are pressed.
 *
 * @param config        Keyboard config
 */
static void check_for_keys(struct keyb *config)
{
        int fifo_cnt;

        if (!config->first_scan &&
                        get_timer(config->last_poll_ms) < KBC_REPEAT_RATE_MS)
                return;
        config->last_poll_ms = get_timer(0);
        config->first_scan = 0;

        /*
         * Once we get here we know the keyboard has been scanned. So if there
         * scan waiting for us, we know that nothing is held down.
         */
        fifo_cnt = (readl(&config->kbc->interrupt) >> 4) & 0xf;
        process_fifo(config, fifo_cnt);
}

/**
 * In order to detect keys pressed on boot, wait for the hardware to
 * complete scanning the keys. This includes time to transition from
 * Wkup mode to Continous polling mode and the repoll time. We can
 * deduct the time that's already elapsed.
 *
 * @param config        Keyboard config
 */
static void kbd_wait_for_fifo_init(struct keyb *config)
{
        if (!config->inited) {
                unsigned long elapsed_time;
                long delay_ms;

                elapsed_time = get_timer(config->start_time_ms);
                delay_ms = config->init_dly_ms - elapsed_time;
                if (delay_ms > 0) {
                        udelay(delay_ms * 1000);
                        debug("%s: delay %ldms\n", __func__, delay_ms);
                }

                config->inited = 1;
        }
}

/**
 * Check the tegra keyboard, and send any keys that are pressed.
 *
 * This is called by input_tstc() and input_getc() when they need more
 * characters
 *
 * @param input         Input configuration
 * @return 1, to indicate that we have something to look at
 */
int tegra_kbc_check(struct input_config *input)
{
        kbd_wait_for_fifo_init(&config);
        check_for_keys(&config);

        return 1;
}

/**
 * Test if keys are available to be read
 *
 * @return 0 if no keys available, 1 if keys are available
 */
static int kbd_tstc(void)
{
        /* Just get input to do this for us */
        return input_tstc(&config.input);
}

/**
 * Read a key
 *
 * TODO: U-Boot wants 0 for no key, but Ctrl-@ is a valid key...
 *
 * @return ASCII key code, or 0 if no key, or -1 if error
 */
static int kbd_getc(void)
{
        /* Just get input to do this for us */
        return input_getc(&config.input);
}

/* configures keyboard GPIO registers to use the rows and columns */
static void config_kbc_gpio(struct kbc_tegra *kbc)
{
        int i;

        for (i = 0; i < KBC_MAX_GPIO; i++) {
                u32 row_cfg, col_cfg;
                u32 r_shift = 5 * (i % 6);
                u32 c_shift = 4 * (i % 8);
                u32 r_mask = 0x1f << r_shift;
                u32 c_mask = 0xf << c_shift;
                u32 r_offs = i / 6;
                u32 c_offs = i / 8;

                row_cfg = readl(&kbc->row_cfg[r_offs]);
                col_cfg = readl(&kbc->col_cfg[c_offs]);

                row_cfg &= ~r_mask;
                col_cfg &= ~c_mask;

                if (i < config.matrix.num_rows) {
                        row_cfg |= ((i << 1) | 1) << r_shift;
                } else {
                        col_cfg |= (((i - config.matrix.num_rows) << 1) | 1)
                                        << c_shift;
                }

                writel(row_cfg, &kbc->row_cfg[r_offs]);
                writel(col_cfg, &kbc->col_cfg[c_offs]);
        }
}

/**
 * Start up the keyboard device
 */
static void tegra_kbc_open(void)
{
        struct kbc_tegra *kbc = config.kbc;
        unsigned int scan_period;
        u32 val;

        /*
         * We will scan at twice the keyboard repeat rate, so that there is
         * always a scan ready when we check it in check_for_keys().
         */
        scan_period = KBC_REPEAT_RATE_MS / 2;
        writel(scan_period * KBC_CLOCK_KHZ, &kbc->rpt_dly);
        writel(scan_period * KBC_CLOCK_KHZ, &kbc->init_dly);
        /*
         * Before reading from the keyboard we must wait for the init_dly
         * plus the rpt_delay, plus 2ms for the row scan time.
         */
        config.init_dly_ms = scan_period * 2 + 2;

        val = KBC_DEBOUNCE_COUNT << KBC_DEBOUNCE_CNT_SHIFT;
        val |= 1 << KBC_FIFO_TH_CNT_SHIFT;      /* fifo interrupt threshold */
        val |= KBC_CONTROL_KBC_EN;              /* enable */
        writel(val, &kbc->control);

        config.start_time_ms = get_timer(0);
        config.last_poll_ms = config.next_repeat_ms = get_timer(0);
        config.first_scan = 1;
}

/**
 * Set up the tegra keyboard. This is called by the stdio device handler
 *
 * We want to do this init when the keyboard is actually used rather than
 * at start-up, since keyboard input may not currently be selected.
 *
 * Once the keyboard starts there will be a period during which we must
 * wait for the keyboard to init. We do this only when a key is first
 * read - see kbd_wait_for_fifo_init().
 *
 * @return 0 if ok, -ve on error
 */
static int init_tegra_keyboard(void)
{
        /* check if already created */
        if (config.created)
                return 0;

#ifdef CONFIG_OF_CONTROL
        int     node;

        node = fdtdec_next_compatible(gd->fdt_blob, 0,
                                          COMPAT_NVIDIA_TEGRA20_KBC);
        if (node < 0) {
                debug("%s: cannot locate keyboard node\n", __func__);
                return node;
        }
        config.kbc = (struct kbc_tegra *)fdtdec_get_addr(gd->fdt_blob,
                       node, "reg");
        if ((fdt_addr_t)config.kbc == FDT_ADDR_T_NONE) {
                debug("%s: No keyboard register found\n", __func__);
                return -1;
        }
        input_set_delays(&config.input, KBC_REPEAT_DELAY_MS,
                        KBC_REPEAT_RATE_MS);

        /* Decode the keyboard matrix information (16 rows, 8 columns) */
        if (key_matrix_init(&config.matrix, 16, 8, 1)) {
                debug("%s: Could not init key matrix\n", __func__);
                return -1;
        }
        if (key_matrix_decode_fdt(&config.matrix, gd->fdt_blob, node)) {
                debug("%s: Could not decode key matrix from fdt\n", __func__);
                return -1;
        }
        if (config.matrix.fn_keycode) {
                if (input_add_table(&config.input, KEY_FN, -1,
                                    config.matrix.fn_keycode,
                                    config.matrix.key_count))
                        return -1;
        }
#else
#error "Tegra keyboard driver requires FDT definitions"
#endif

        /* Set up pin mux and enable the clock */
        funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
        clock_enable(PERIPH_ID_KBC);
        config_kbc_gpio(config.kbc);

        tegra_kbc_open();
        config.created = 1;
        debug("%s: Tegra keyboard ready\n", __func__);

        return 0;
}

int drv_keyboard_init(void)
{
        struct stdio_dev dev;
        char *stdinname = getenv("stdin");
        int error;

        if (input_init(&config.input, 0)) {
                debug("%s: Cannot set up input\n", __func__);
                return -1;
        }
        config.input.read_keys = tegra_kbc_check;

        memset(&dev, '\0', sizeof(dev));
        strcpy(dev.name, "tegra-kbc");
        dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
        dev.getc = kbd_getc;
        dev.tstc = kbd_tstc;
        dev.start = init_tegra_keyboard;

        /* Register the device. init_tegra_keyboard() will be called soon */
        error = input_stdio_register(&dev);
        if (error)
                return error;
#ifdef CONFIG_CONSOLE_MUX
        error = iomux_doenv(stdin, stdinname);
        if (error)
                return error;
#endif
        return 0;
}