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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Tuner "middleware" for Silicon Labs SI4700 chip
*
* Copyright (C) 2008 Nils Wallménius
*
* 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 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include "kernel.h"
#include "tuner.h" /* tuner abstraction interface */
#include "fmradio.h"
#include "fmradio_i2c.h" /* physical interface driver */
#define I2C_ADR 0x20
/* I2C writes start at register 02h so the first two bytes are
02h, next two 03h, etc. */
static unsigned char write_bytes[8]; /* registers 02 - 05 */
static bool tuner_present = false;
void si4700_init(void)
{
unsigned char read_bytes[32];
tuner_power(true);
fmradio_i2c_read(I2C_ADR, read_bytes, sizeof(read_bytes));
if ((read_bytes[12] << 8 | read_bytes[13]) == 0x1242)
{
tuner_present = true;
/* fill in the initial values in write_bytes */
memcpy(&write_bytes[0], &read_bytes[16], sizeof(write_bytes));
/* -6dB volume, keep everything else as default */
write_bytes[7] = (write_bytes[7] & ~0xf) | 0xc;
}
tuner_power(false);
}
static void si4700_tune(void)
{
unsigned char read_bytes[1];
write_bytes[2] |= (1 << 7); /* Set TUNE high to start tuning */
fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
do
{
sleep(HZ/50);
fmradio_i2c_read(I2C_ADR, read_bytes, 1);
}
while (!(read_bytes[0] & (1 << 6))); /* STC high == Seek/Tune complete */
write_bytes[2] &= ~(1 << 7); /* Set TUNE low */
fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
}
/* tuner abstraction layer: set something to the tuner */
int si4700_set(int setting, int value)
{
switch(setting)
{
case RADIO_SLEEP:
if (value)
{
write_bytes[1] = (1 | (1 << 6)); /* ENABLE high, DISABLE high */
}
else
{
write_bytes[1] = 1; /* ENABLE high, DISABLE low */
}
break;
case RADIO_FREQUENCY:
{
static const unsigned int spacings[3] =
{
200000, 100000, 50000
};
unsigned int chan;
unsigned int spacing = spacings[(write_bytes[7] >> 4) & 3] ;
if (write_bytes[7] & (3 << 6)) /* check BAND */
{
chan = (value - 76000000) / spacing;
}
else
{
chan = (value - 87500000) / spacing;
}
write_bytes[2] = (write_bytes[2] & ~3) | ((chan & (3 << 8)) >> 8);
write_bytes[3] = (chan & 0xff);
fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
si4700_tune();
return 1;
}
case RADIO_SCAN_FREQUENCY:
si4700_set(RADIO_FREQUENCY, value);
return 1;
case RADIO_MUTE:
if (value)
{
/* mute */
write_bytes[0] &= ~(1 << 6);
}
else
{
/* unmute */
write_bytes[0] |= (1 << 6);
}
break;
case RADIO_REGION:
{
const struct si4700_region_data *rd =
&si4700_region_data[value];
write_bytes[4] = ((write_bytes[4] & ~(1 << 3)) | (rd->deemphasis << 3));
write_bytes[7] = ((write_bytes[7] & ~(3 << 6)) | (rd->band << 6));
write_bytes[7] = ((write_bytes[7] & ~(3 << 4)) | (rd->spacing << 4));
break;
}
case RADIO_FORCE_MONO:
if (value)
{
write_bytes[0] |= (1 << 5);
}
else
{
write_bytes[0] &= ~(1 << 5);
}
break;
default:
return -1;
}
fmradio_i2c_write(I2C_ADR, write_bytes, sizeof(write_bytes));
return 1;
}
/* tuner abstraction layer: read something from the tuner */
int si4700_get(int setting)
{
/* I2C reads start with register 0xA */
unsigned char read_bytes[1];
int val = -1; /* default for unsupported query */
switch(setting)
{
case RADIO_PRESENT:
val = tuner_present ? 1 : 0;
break;
case RADIO_TUNED:
val = 1;
break;
case RADIO_STEREO:
fmradio_i2c_read(I2C_ADR, read_bytes, sizeof(read_bytes));
val = (read_bytes[0] & 1); /* ST high == Stereo */
break;
}
return val;
}
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