/**
 * \file ks0108.c
 * \brief KS0108 graphical LCD support
 *
 * \subsection Copyright
 * Copyright (c) 2013-2022 Michael Buesch <m@bues.ch>
 *
 * \subsection License
 * Licensed under the terms of the GNU General Public License version 2.
 */

#include "ks0108.h"
#include "output_extender.h"
#include "util.h"
#include "main.h"

#include <avr/io.h>


/** Kommando-ID: Display control. */
#define KS0108_CMD_DISPLAYCTL(on)	(0x3E | ((on) ? 1 : 0))
/** Kommando-ID: Adresse setzen. */
#define KS0108_CMD_SETADDR(addr)	(0x40 | ((addr) & 0x3F))
/** Kommando-ID: Seite setzen. */
#define KS0108_CMD_SETPAGE(page)	(0xB8 | ((page) & 0x07))
/** Kommando-ID: Startzeile setzen. */
#define KS0108_CMD_STARTLN(line)	(0xC0 | ((line) & 0x3F))

/** Status bits */
enum ks0108_status_bits {
	/** Status bit: LCD verarbeitet einen Befehl. */
	KS0108_STAT_BUSY		= 0x80,
	/** Status bit: LCD ist abgeschaltet. */
	KS0108_STAT_OFF			= 0x20,
	/** Status bit: LCD ist im Reset. */
	KS0108_STAT_RESET		= 0x10,
};

/** \brief	Datenpins initialisieren. */
static inline void ks0108_pins_init(void)
{
#if BOARDID == BOARDID_PLAIN
	PORTB &= ~(1 << 5);
	DDRB |= 1 << 5;
#elif BOARDID == BOARDID_MYAVR
	/* Nothing to do. */
#else
# error "Unknown board."
#endif
}

/** \brief	Datenrichtung der Datenpins konfigurieren.
 *
 * \param out		1: Ausgang.
 *			0: Eingang.
 */
static inline void ks0108_data_direction(bool out)
{
#if BOARDID == BOARDID_PLAIN
	if (out) {
		DDRD = 0xFF;
	} else {
		PORTD = 0;
		DDRD = 0;
	}
#elif BOARDID == BOARDID_MYAVR
	if (out) {
		DDRD |= 0xFC;
		DDRB |= 0x30;
	} else {
		PORTD &= ~0xFC;
		DDRD &= ~0xFC;
		PORTB &= ~0x30;
		DDRB &= ~0x30;
	}
#else
# error "Unknown board."
#endif
}

/** \brief	Datenpins einlesen.
 *
 * \return		Gibt das Datenbyte zurueck.
 */
static inline uint8_t ks0108_read_data(void)
{
#if BOARDID == BOARDID_PLAIN
	return PIND;
#elif BOARDID == BOARDID_MYAVR
	return ((PIND & 0xFC) >> 2) | ((PINB & 0x30) << 2);
#else
# error "Unknown board."
#endif
}

/** \brief	Datenpins schreiben.
 *
 * \param data		Das Datenbyte.
 */
static inline void ks0108_write_data(uint8_t data)
{
#if BOARDID == BOARDID_PLAIN
	PORTD = data;
#elif BOARDID == BOARDID_MYAVR
	PORTD = (PORTD & ~0xFC) | (data << 2);
	PORTB = (PORTB & ~0x30) | ((data & 0xC0) >> 2);
#else
# error "Unknown board."
#endif
}

/** \brief	RESET pin setzen/ruecksetzen.
 *
 * \param rst		1: Setzen.
 *			0: Ruecksetzen.
 */
static inline void ks0108_control_rst(bool rst)
{
	extout_write_bit(EXTOUT_LCD_RST, rst);
}

/** \brief	CHIPSELECT pins setzen/ruecksetzen.
 *
 * \param cs1		1: Setzen.
 *			0: Ruecksetzen.
 *
 * \param cs2		1: Setzen.
 *			0: Ruecksetzen.
 */
static inline void ks0108_control_cs(bool cs1, bool cs2)
{
	extout_write_bit(EXTOUT_LCD_CS1, cs1);
	extout_write_bit(EXTOUT_LCD_CS2, cs2);
}

/** \brief	DI pin setzen/ruecksetzen.
 *
 * \param di		1: Setzen.
 *			0: Ruecksetzen.
 */
static inline void ks0108_control_di(bool di)
{
	extout_write_bit(EXTOUT_LCD_DI, di);
}

/** \brief	RW pin setzen/ruecksetzen.
 *
 * \param rw		1: Setzen.
 *			0: Ruecksetzen.
 */
static inline void ks0108_control_rw(bool rw)
{
	extout_write_bit(EXTOUT_LCD_RW, rw);
}

/** \brief	E pin setzen/ruecksetzen.
 *
 * \param e		1: Setzen.
 *			0: Ruecksetzen.
 */
static inline void ks0108_control_e(bool e)
{
#if BOARDID == BOARDID_PLAIN
	if (e)
		PORTB |= 1 << 5;
	else
		PORTB &= ~(1 << 5);
#elif BOARDID == BOARDID_MYAVR
	extout_write_bit(EXTOUT_LCD_E, e);
#else
# error "Unknown board."
#endif
}

/** \brief	Control bits auf die Hardware uebertragen. */
static inline void ks0108_write_control_bits(void)
{
	extout_commit();
}

/** \brief	Daten/Status vom LCD lesen.
 *
 * \param di		1: Daten.
 *			0: Status.
 */
static uint8_t ks0108_read(uint8_t di)
{
	uint8_t data;

	ks0108_data_direction(0);
	ks0108_control_di(di);
	ks0108_control_rw(1);
	ks0108_write_control_bits();
	ks0108_control_e(1);
	ks0108_write_control_bits();
	_NOP();
	data = ks0108_read_data();
	ks0108_control_e(0);
	ks0108_write_control_bits();

	return data;
}

/** \brief	Daten/Instruktion auf das LCD schreiben.
 *
 * \param di		1: Daten.
 *			0: Instruktion.
 *
 * \param data		Die zu schreibenden Daten.
 */
static void ks0108_write(uint8_t di, uint8_t data)
{
	ks0108_control_di(di);
	ks0108_control_rw(0);
	ks0108_write_control_bits();
	ks0108_data_direction(1);
	ks0108_write_data(data);
	ks0108_control_e(1);
	ks0108_write_control_bits();
	_NOP();
	ks0108_control_e(0);
	ks0108_write_control_bits();
}

/** \brief	Statusregister des LCD lesen.
 *
 * \return		Gibt den Inhalt des Statusregisters zurueck.
 */
static uint8_t ks0108_req_read_status(void)
{
	return ks0108_read(0);
}

/** \brief	Warte solange das BUSY bit im LCD status Register
  *		gesetzt ist.
  */
static void ks0108_busy_wait(void)
{
	while (ks0108_req_read_status() & KS0108_STAT_BUSY);
}

/** \brief	Kommando an das LCD senden.
 *
 * \param command	Das zu sendende Kommando.
 */
static void ks0108_req_command(uint8_t command)
{
	ks0108_busy_wait();
	ks0108_write(0, command);
}

/** \brief	Daten an das LCD senden.
 *
 * \param data		Die zu sendenden Daten.
 */
static void ks0108_req_write_data(uint8_t data)
{
	ks0108_busy_wait();
	ks0108_write(1, data);
}

#if 0
/** \brief	Daten vom LCD lesen.
 *
 * \return		Gibt die Daten zurueck.
 **/
static uint8_t ks0108_req_read_data(void)
{
	ks0108_busy_wait();
	return ks0108_read(1);
}
#endif

/** \brief	 LCD Chipselect setzen.
 *
 * \param nr		Zu setzende Chipnummer. 0 oder 1.
 */
static void ks0108_chipselect(uint8_t nr)
{
	if (nr == 0)
		ks0108_control_cs(1, 0);
	else
		ks0108_control_cs(0, 1);
}

/** \brief	 Ein Bitmap auf dem LCD zeichnen.
 *
 * \param bitmap	Das zu zeichnende Bitmap.
 *			Wenn NULL, dann werden die Pixel geloescht.
 *
 * \param x		Absolute X Startkoordinate auf dem LCD.
 *
 * \param y		Absolute Y Startkoordinate auf dem LCD.
 *
 * \param width		Breite des zu zeichnenden Bereiches.
 *
 * \param height	Hoehe des zu zeichnenden Bereiches.
 */
static void draw_bitmap(const struct bitmap *bitmap,
			uint8_t x, uint8_t y,
			uint8_t width, uint8_t height)
{
	uint8_t xx, yy;
	uint8_t current_chip, chip;
	uint8_t addr, data = 0;

	y /= 8;
	height /= 8;

	for (yy = y; yy < y + height; yy++) {
		current_chip = -1;
		for (xx = x; xx < x + width; xx++) {
			chip = xx / KS0108_WIDTHPIX_PER_CHIP;
			addr = xx % KS0108_WIDTHPIX_PER_CHIP;
			if (chip != current_chip) {
				current_chip = chip;
				ks0108_chipselect(chip);
				ks0108_req_command(KS0108_CMD_SETPAGE(yy));
				ks0108_req_command(KS0108_CMD_SETADDR(addr));
			}
			if (bitmap) {
				data = *bitmap_column_byte(bitmap,
					xx - x, (yy - y) * 8);
			}
			ks0108_req_write_data(data);
		}
	}
}

/** \brief	Ein Bitmap auf dem LCD zeichnen.
 *
 * \param bitmap	Das zu zeichnende Bitmap.
 *
 * \param x		Absolute X Startkoordinate auf dem LCD.
 *
 * \param y		Absolute Y Startkoordinate auf dem LCD.
 */
void ks0108_draw_bitmap(const struct bitmap *bitmap,
			uint8_t x, uint8_t y)
{
	draw_bitmap(bitmap, x, y, bitmap->width, bitmap->height);
}

/** \brief	LCD initialisieren. */
void ks0108_init(void)
{
	uint8_t chip;

	/* Pins initialisieren. */
	ks0108_pins_init();
	ks0108_data_direction(0);
	ks0108_control_rst(0);
	ks0108_write_control_bits();
	ks0108_chipselect(0);
	ks0108_control_di(0);
	ks0108_control_rw(0);
	ks0108_control_e(0);
	ks0108_write_control_bits();
	_delay_us(10);

	/* LCD aus dem RESET Status nehmen. */
	ks0108_control_rst(1);
	ks0108_write_control_bits();
	_delay_us(10);

	/* LCD einschalten und Startzeile setzen. */
	for (chip = 0; chip < KS0108_NR_CHIPS; chip++) {
		ks0108_chipselect(chip);
		ks0108_req_command(KS0108_CMD_DISPLAYCTL(1));
		ks0108_req_command(KS0108_CMD_STARTLN(0));
	}

	/* Alle Pixel loeschen. */
	draw_bitmap(NULL, 0, 0, KS0108_WIDTH, KS0108_HEIGHT);
}