/*
   *  (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
  ", __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
   */
  static 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(struct stdio_dev *dev)
  {
  	/* 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(struct stdio_dev *dev)
  {
  	/* 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(struct stdio_dev *dev)
  {
  	/* 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
  ", __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
  ", __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
  ", __func__);
  		return -1;
  	}
  	if (key_matrix_decode_fdt(&config.matrix, gd->fdt_blob, node)) {
  		debug("%s: Could not decode key matrix from fdt
  ", __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
  ", __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
  ", __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;
  }