/*   USBTenki - Interfacing sensors to USB
 *   Copyright (C) 2007-2011  Raphaël Assénat <raph@raphnet.net>
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "interface.h"
#include "usbtenki_cmds.h"
#include "i2c.h"
#include "tsl256x.h"
#include <avr/io.h>

/* USBTenki head PCB connects address select to GND */
#define TSL2561_ADDR    (TSL2561_ADDRESS_GND)

#if 0
#define DEBUG_LOW()		do { PORTC &= 0xFE; } while(0)
#define DEBUG_HIGH()	do { PORTC |= 0x01; } while(0)
#else
#define DEBUG_HIGH()
#define DEBUG_LOW()
#endif

int sensors_init(void)
{
	unsigned char tmp;
	char res;

	i2c_init(I2C_FLAG_EXTERNAL_PULLUP, 55);

	/* Powerup the chip */
	tmp = 0x03;
	res = tsl2561_writeRegister(TSL2561_ADDR,
				TSL2561_REG_CONTROL | TSL2561_CMD_CMD, &tmp, 1);
	if (res)
		return res;

	/* Setup gain and timing */
	tmp = 0x02;	// Integration time nominal 402ms
	res = tsl2561_writeRegister(TSL2561_ADDR,
				TSL2561_REG_TIMING | TSL2561_CMD_CMD, &tmp, 1);
	if (res)
		return res;

	tmp = 0x00;	// No interrupts (0x00 is default value)
	res = tsl2561_writeRegister(TSL2561_ADDR,
				TSL2561_REG_TIMING | TSL2561_CMD_CMD, &tmp, 1);
	if (res)
		return res;

	// PORTC0 debug
	DDRC |= 0x01;
	DEBUG_LOW();

	return 0;
}

static int switchGain(int gain_16x)
{
	static char last_16x = 0;
	unsigned char tmp;
	char res;

	if (last_16x != gain_16x) {
		tmp = 0x02;	// Integration time nominal 402ms
		if (gain_16x)
			tmp |= 0x10;	// 16x gain
		res = tsl2561_writeRegister(TSL2561_ADDR,
				TSL2561_REG_TIMING | TSL2561_CMD_CMD, &tmp, 1);
		if (res)
			return res;

		// Nominal integration time : 402ms.
		// If the gain is switched to 16x during an integration
		// cycle, this cycle result will be invalid. We must
		// therefore wait until another cycle completes, hence
		// the double delay.
		DEBUG_HIGH();
		usbtenki_delay_ms(415);
		usbtenki_delay_ms(415);
		DEBUG_LOW();
	}

	last_16x = gain_16x;

	return 0;
}

int sensors_getRaw(unsigned char id, unsigned char *dst)
{
	char res;

	dst[0] = 0x00;
	dst[1] = 0x00;

	switch(id)
	{
		case 0:
			res = switchGain(0);
			if (res)
				return res;

			res = tsl2561_readRegister(TSL2561_ADDR,
					TSL2561_CMD_CMD | TSL2561_CMD_WORD | TSL2561_REG_DATA0_L,
					dst, 2);
			if (res)
				return res;
			break;
		case 1:
			res = switchGain(0);
			if (res)
				return res;
			res = tsl2561_readRegister(TSL2561_ADDR,
				 	TSL2561_CMD_CMD | TSL2561_CMD_WORD | TSL2561_REG_DATA1_L,
					dst, 2);
			if (res)
				return res;
			break;
		case 2:
			res = switchGain(1);
			if (res)
				return res;

			res = tsl2561_readRegister(TSL2561_ADDR,
					TSL2561_CMD_CMD | TSL2561_CMD_WORD | TSL2561_REG_DATA0_L,
					dst, 2);
			if (res)
				return res;
			break;
		case 3:
			res = switchGain(1);
			if (res)
				return res;

			res = tsl2561_readRegister(TSL2561_ADDR,
					TSL2561_CMD_CMD | TSL2561_CMD_WORD | TSL2561_REG_DATA1_L,
					dst, 2);
			if (res)
				return res;
			break;

	}

	return 2;
}