/*
 * aitendo M6955 dsp radio module control
 * File:   i2c_m6955.c
 * Author: www.henteko.org
 *
 * Created on 2013/11/15, 17:50
 */ 

#include <util/delay.h>
#include "i2c_m6955.h"

void i2c_m6955_send(unsigned char reg, unsigned char data)
{
	TinyI2C_start();
	TinyI2C_write(0x20);
	TinyI2C_write(reg);
	TinyI2C_write(data);
	TinyI2C_stop();
}

unsigned char i2c_m6955_recv(unsigned char reg)
{
	unsigned char c;

	TinyI2C_start();
	TinyI2C_write(0x20);
	TinyI2C_write(reg);
	TinyI2C_start();
	TinyI2C_write(0x20 | 1);
	c = TinyI2C_read(0);
	TinyI2C_stop();

	_delay_us(30);

	return c;
}

void i2c_m6955_set_band(unsigned char band)
{
	if(band == 0) {
		i2c_m6955_send(0, 0b10000000);	// set mode AM
		i2c_m6955_send(1, 0b00010001);	// set band WM2 and FM2
	} else if(band == 1) {
		i2c_m6955_send(0, 0b11000000);	// set mode FM
		i2c_m6955_send(1, 0b00010001);	// set band WM2 and FM2
	} else {
		i2c_m6955_send(0, 0b10000000);	// set mode AM
		i2c_m6955_send(1, 0b01000001);	// set band SW5 and FM2
	}
}

void i2c_m6955_tune(unsigned char mode)
{
	if(mode == 1) {		// FM mode
		i2c_m6955_send(0, 0b11000000);
		_delay_ms(1);
		i2c_m6955_send(0, 0b11100000);	// tune 0->1
		_delay_ms(1);
		i2c_m6955_send(0, 0b11000000);
	} else {			// AM mode
		i2c_m6955_send(0, 0b10000000);
		_delay_ms(1);
		i2c_m6955_send(0, 0b10100000);	// tune 0->1
		_delay_ms(1);
		i2c_m6955_send(0, 0b10000000);
	}
}

void i2c_m6955_set_freq(unsigned char band, unsigned int freq)
{
	unsigned int ch;

	if(band == 1) {			// set fm freq
		ch = ((freq - 3000) * 10) / 25;
	} else if(band == 0) {	// set wm freq
        ch = (freq / 9) * 3;
	} else {				// set sw freq
		ch = freq / 5;
	}
	i2c_m6955_send(3, (ch & 0xff));
	i2c_m6955_send(2, ((ch >> 8) | 0x40));

	i2c_m6955_tune(band);
}

unsigned int i2c_m6955_get_freq(unsigned char band)
{
	unsigned int freq;
	unsigned char high, low;
	unsigned int ch;

	low = i2c_m6955_recv(3) ;
	high = i2c_m6955_recv(2) & 0x1f;
	ch = (high << 8) | low;

	if(band == 0) {			// MW band
		freq = ch * 3;
	} else if(band == 1) {	// FM band
	    freq = (ch * 5) / 2 + 3000;
	} else {				// SW band
	   freq = ch * 5;
	}
	return freq;
}

void i2c_m6955_init()
{
	i2c_m6955_send(0, 0b11000000);	// b7=power on, b6=fmmode
	i2c_m6955_send(6, 0b01100001);	// b7:2=volume 48/64, b1:radio mode
									// b0:signal fhase 0:dual 1:single
	i2c_m6955_send(7, 0b00110001);	// b5=base boost, b3:2=auto stereo
	i2c_m6955_send(9, 0b00000111);	// b3=vol control resistor, b2=Xtal
}

int i2c_m6955_siglevel(unsigned char band)
{
	unsigned int pga_rf, pga_if, rssi;
	unsigned char tmp;
	int level;

	tmp = i2c_m6955_recv(24);
	pga_rf = tmp & 0xe0 >> 5;
	pga_if = tmp & 0x1c >> 2;
	rssi = i2c_m6955_recv(27) & 0x7f;

	if(band == 1)
		level = 103 - rssi - 6 * pga_rf - 6 * pga_if;
	else
		level = 123 - rssi - 6 * pga_rf - 6 * pga_if;

	return level;
}

void i2c_m6955_off(void)
{
	i2c_m6955_send(0, 0b00000000);
}