// SPDX-License-Identifier: GPL-2.0+

  /*
   *  (C) Copyright 2011
   *  NVIDIA Corporation <www.nvidia.com>

   */
  
  #include <common.h>

  #include <dm.h>

  #include <fdtdec.h>
  #include <input.h>

  #include <keyboard.h>

  #include <key_matrix.h>

  #include <log.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/delay.h>

  #include <linux/input.h>

  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 */

  struct tegra_kbd_priv {
  	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 */
  
  	/*
  	 * 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 */

  };

  
  /**
   * reads the keyboard fifo for current keypresses
   *

   * @param priv		Keyboard private data

   * @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 tegra_kbd_priv *priv, 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(&priv->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(&priv->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 priv		Keyboard private data

   * @param fifo_cnt	Number of entries in the keyboard fifo
   */

  static void process_fifo(struct tegra_kbd_priv *priv, 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(priv, fifo, KBC_MAX_KPENT);

  		input_send_keycodes(priv->input, fifo, cnt);

  	} while (--fifo_cnt > 0);
  }
  
  /**
   * Check the keyboard controller and emit ASCII characters for any keys that
   * are pressed.
   *

   * @param priv		Keyboard private data

   */

  static void check_for_keys(struct tegra_kbd_priv *priv)

  {
  	int fifo_cnt;

  	if (!priv->first_scan &&
  	    get_timer(priv->last_poll_ms) < KBC_REPEAT_RATE_MS)

  		return;

  	priv->last_poll_ms = get_timer(0);
  	priv->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(&priv->kbc->interrupt) >> 4) & 0xf;
  	process_fifo(priv, 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 priv		Keyboard private data

   */

  static void kbd_wait_for_fifo_init(struct tegra_kbd_priv *priv)

  {

  	if (!priv->inited) {

  		unsigned long elapsed_time;
  		long delay_ms;

  		elapsed_time = get_timer(priv->start_time_ms);
  		delay_ms = priv->init_dly_ms - elapsed_time;

  		if (delay_ms > 0) {
  			udelay(delay_ms * 1000);
  			debug("%s: delay %ldms
  ", __func__, delay_ms);
  		}

  		priv->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

   */

  static int tegra_kbc_check(struct input_config *input)

  {

  	struct tegra_kbd_priv *priv = dev_get_priv(input->dev);

  	kbd_wait_for_fifo_init(priv);
  	check_for_keys(priv);

  	return 1;

  }
  
  /* configures keyboard GPIO registers to use the rows and columns */

  static void config_kbc_gpio(struct tegra_kbd_priv *priv, 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 < priv->matrix.num_rows) {

  			row_cfg |= ((i << 1) | 1) << r_shift;
  		} else {

  			col_cfg |= (((i - priv->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(struct tegra_kbd_priv *priv)

  {

  	struct kbc_tegra *kbc = priv->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.
  	 */

  	priv->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);

  	priv->start_time_ms = get_timer(0);
  	priv->last_poll_ms = get_timer(0);
  	priv->next_repeat_ms = priv->last_poll_ms;
  	priv->first_scan = 1;
  }
  
  static int tegra_kbd_start(struct udevice *dev)
  {
  	struct tegra_kbd_priv *priv = dev_get_priv(dev);
  
  	/* Set up pin mux and enable the clock */
  	funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
  	clock_enable(PERIPH_ID_KBC);
  	config_kbc_gpio(priv, priv->kbc);
  
  	tegra_kbc_open(priv);
  	debug("%s: Tegra keyboard ready
  ", __func__);
  
  	return 0;

  }
  
  /**
   * 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 tegra_kbd_probe(struct udevice *dev)

  {

  	struct tegra_kbd_priv *priv = dev_get_priv(dev);
  	struct keyboard_priv *uc_priv = dev_get_uclass_priv(dev);
  	struct stdio_dev *sdev = &uc_priv->sdev;
  	struct input_config *input = &uc_priv->input;

  	int ret;

  	priv->kbc = dev_read_addr_ptr(dev);

  	if ((fdt_addr_t)priv->kbc == FDT_ADDR_T_NONE) {

  		debug("%s: No keyboard register found
  ", __func__);

  		return -EINVAL;

  	}

  	input_set_delays(input, KBC_REPEAT_DELAY_MS, KBC_REPEAT_RATE_MS);

  
  	/* Decode the keyboard matrix information (16 rows, 8 columns) */

  	ret = key_matrix_init(&priv->matrix, 16, 8, 1);
  	if (ret) {
  		debug("%s: Could not init key matrix: %d
  ", __func__, ret);
  		return ret;

  	}

  	ret = key_matrix_decode_fdt(dev, &priv->matrix);

  	if (ret) {
  		debug("%s: Could not decode key matrix from fdt: %d
  ",
  		      __func__, ret);
  		return ret;

  	}

  	input_add_tables(input, false);

  	if (priv->matrix.fn_keycode) {
  		ret = input_add_table(input, KEY_FN, -1,
  				      priv->matrix.fn_keycode,
  				      priv->matrix.key_count);
  		if (ret) {
  			debug("%s: input_add_table() failed
  ", __func__);
  			return ret;
  		}

  	}

  	/* Register the device. init_tegra_keyboard() will be called soon */
  	priv->input = input;
  	input->dev = dev;
  	input->read_keys = tegra_kbc_check;

  	strcpy(sdev->name, "tegra-kbc");
  	ret = input_stdio_register(sdev);
  	if (ret) {
  		debug("%s: input_stdio_register() failed
  ", __func__);
  		return ret;
  	}

  
  	return 0;
  }

  static const struct keyboard_ops tegra_kbd_ops = {
  	.start	= tegra_kbd_start,
  };

  static const struct udevice_id tegra_kbd_ids[] = {
  	{ .compatible = "nvidia,tegra20-kbc" },
  	{ }
  };

  U_BOOT_DRIVER(tegra_kbd) = {
  	.name	= "tegra_kbd",
  	.id	= UCLASS_KEYBOARD,
  	.of_match = tegra_kbd_ids,
  	.probe = tegra_kbd_probe,
  	.ops	= &tegra_kbd_ops,

  	.priv_auto	= sizeof(struct tegra_kbd_priv),

  };