/* -------------------------------------------------------------------------------------------------- */
/* The LongMynd receiver: stv6120.c                                                                   */
/*    - an implementation of the Serit NIM controlling software for the MiniTiouner Hardware          */
/*    - the stv6120 (tuner) specific routines                                                         */
/* Copyright 2019 Heather Lomond                                                                      */
/* -------------------------------------------------------------------------------------------------- */
/*
    This file is part of longmynd.

    Longmynd 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.

    Longmynd 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 longmynd.  If not, see <https://www.gnu.org/licenses/>.
*/

/* -------------------------------------------------------------------------------------------------- */
/* ----------------- INCLUDES ----------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */

#include "math.h"
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include "nim.h"
#include "stv6120.h"
#include "stv6120_regs.h"
#include "stv6120_utils.h"
#include "errors.h"

/* -------------------------------------------------------------------------------------------------- */
/* ----------------- GLOBALS ------------------------------------------------------------------------ */
/* -------------------------------------------------------------------------------------------------- */

/* some globals to make it easier to keep track of register contents across function calls */
uint8_t rdiv;
uint8_t ctrl7;
uint8_t ctrl8;
uint8_t ctrl16;
uint8_t ctrl17;

/* -------------------------------------------------------------------------------------------------- */
/* ----------------- CONSTANTS ---------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */

/* from the datasheet: charge pump data */
const uint32_t stv6120_icp_lookup[7][3]={
     /* low     high  icp */
    {2380000, 2472000, 0},
    {2473000, 2700000, 1},  
    {2701000, 3021000, 2},  
    {3022000, 3387000, 3},
    {3388000, 3845000, 5},
    {3846000, 4394000, 6},
    {4395000, 4760000, 7} 
};

/* a lookup table for the cutuff freq of the HF filter in MHz */
const uint16_t stv6120_cfhf[32]={6796, 5828, 4778, 4118, 3513, 3136, 2794, 2562,
                            2331, 2169, 2006, 1890, 1771, 1680, 1586, 1514,
                            1433, 1374, 1310, 1262, 1208, 1167, 1122, 1087,
                            1049, 1018,  983,  956,  926,  902,  875,  854};
 
/* -------------------------------------------------------------------------------------------------- */
/* ----------------- ROUTINES ----------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */

/* -------------------------------------------------------------------------------------------------- */
uint8_t stv6120_cal_lowpass(uint8_t tuner) {
/* -------------------------------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */
    uint8_t err=ERROR_NONE;
    uint8_t val;
    uint16_t timeout;

    printf("Flow: Tuner cal lowpass\n");

    /* turn on the clock for the low pass filter. This is in ctrl7/16 so we have a shadow for it */
    if (tuner==TUNER_1) err=stv6120_write_reg(STV6120_CTRL7 ,  ctrl7 & ~(1 << STV6120_CTRL7_RCCLKOFF_SHIFT));
    else                err=stv6120_write_reg(STV6120_CTRL16, ctrl16 & ~(1 << STV6120_CTRL7_RCCLKOFF_SHIFT));
    /* now we can do a low pass filter calibration, by setting the CALRCSTRT bit. NOte it is safe to just write to it */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_STAT1 : STV6120_STAT2,
                                         (STV6120_STAT1_CALRCSTRT_START << STV6120_STAT1_CALRCSTRT_SHIFT));
    /* wait for the bit to be cleared  to say cal has finished*/
    if (err==ERROR_NONE) {
        timeout=0;
        do {
            err=stv6120_read_reg(STV6120_STAT1, &val); 
            timeout++;
            if (timeout==STV6120_CAL_TIMEOUT) {
                err=ERROR_TUNER_CAL_LOWPASS_TIMEOUT;
                printf("ERROR: tuner wait on CAL_lowpass timed out\n");
            }
        } while ((err==ERROR_NONE) && ((val & (1<<STV6120_STAT1_CALRCSTRT_SHIFT)) == (1<<STV6120_STAT1_CALRCSTRT_SHIFT)));
    }
    /* turn off the low pass filter clock (=1) */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_CTRL7 : STV6120_CTRL16,
                                              (tuner==TUNER_1 ? ctrl7 : ctrl16));

    if (err!=ERROR_NONE) printf("ERROR: Failed to cal lowpass filter\n");

    return err;
}

/* -------------------------------------------------------------------------------------------------- */
uint8_t stv6120_set_freq(uint8_t tuner, uint32_t freq) {
/* -------------------------------------------------------------------------------------------------- */
/* Sets one of the tuners to the given frequency                                                      */
/*   tuner: TUNER_1  |  TUNER_2 : which tuner we are going to work on                                 */
/*    freq: the frequency to set the tuner to in KHz                                                  */
/*  return: error code                                                                                */
/*                                                                                                    */
/* when locked,  F.lo = F.vco/P = (F.xtal/R) * (N+F/2^18)/P                                           */
/* -------------------------------------------------------------------------------------------------- */
    uint8_t err=ERROR_NONE;
    uint8_t val;
    uint8_t pos;
    uint32_t f;
    uint16_t n;
    uint8_t p;
    uint8_t icp;
    uint32_t f_vco;
    uint16_t timeout;
    uint8_t cfhf;

    printf("Flow: Tuner set freq\n");

    /* the global rdiv has already been set up in the init routines */

    /* p is defined from the datasheet (note, this is reg value, not P) */
    if      (freq<=STV6120_P_THRESHOLD_1) p=3; /* P=16 */
    else if (freq<=STV6120_P_THRESHOLD_2) p=2; /* P= 8 */
    else if (freq<=STV6120_P_THRESHOLD_3) p=1; /* P= 4 */
    else                                  p=0; /* P= 2 */

    /* we have to be careful of the size of the typesi in the following  */
    /* F.vco=F.rf*P where F.rf=F.lo    all in KHz */
    /* f_vco is uint32_t, so p_max is 3 (i.e P_max is 16), freq_max is 2500000KHz, results is 0x02625a00 ... OK */
    f_vco = freq<<(p+1);
    /* n=integer(f_vco/f_xtal*R)  note: f_xtal and f_vco both in KHz */
    /* we do the *R first (a shift by rdiv), and max is 0x04c4b400, then the divide and we are OK */
    n = (uint16_t)((f_vco << rdiv) / NIM_TUNER_XTAL);
    /* f = fraction(f_vco/f_xtal*R).2^18 */
    /* as for n, we do the shift first (which we know is safe), then modulus to get the fraction */
    /* then we have to go to 64 bits to do the shift and divide, and then back to uint32_t for the result */
    f = (uint32_t)(( ((uint64_t)((f_vco << rdiv) % NIM_TUNER_XTAL)) << 18) / NIM_TUNER_XTAL);
    
    /* lookup the ICP value in the lookup table as per datasheet */
    pos=0;
    while (f_vco > stv6120_icp_lookup[pos++][1]);
    icp=stv6120_icp_lookup[pos-1][2];

    /* lookup the high freq filter cutoff setting as per datasheet */
    cfhf=0;
    while ((3*freq/1000) <= stv6120_cfhf[cfhf]) {
        cfhf++;
    }
    cfhf--; /* we are sure it isn't greater then the first array element so this is safe */

    printf("      Status: tuner:%i, f_vco=0x%x, icp=0x%x, f=0x%x, n=0x%x,\n",tuner,f_vco,icp,f,n);
    printf("              rdiv=0x%x, p=0x%x, freq=%i, cfhf=%i\n",rdiv,p,freq,stv6120_cfhf[cfhf]);

    /* now we fill in the PLL and ICP values */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_CTRL3 : STV6120_CTRL12,
                                            (n & 0x00ff)               );      /* set N[7:0] */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_CTRL4 : STV6120_CTRL13,
                                            ((f & 0x0000007f) << 1)    |       /* set F[6:0] */
                                            ((n & 0x0100)   >> 8)      );      /* N[8] */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_CTRL5 : STV6120_CTRL14,
                                            ((f & 0x00007f80) >> 7)    );      /* set F[14:7] */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_CTRL6 : STV6120_CTRL15,
                                            ((f & 0x00038000) >> 15)   |       /* set f[17:15] */
                                            (icp << STV6120_CTRL6_ICP_SHIFT) | /* ICP[2:0] */
                                            STV6120_CTRL6_RESERVED     );      /* reserved bit */

    if (tuner==TUNER_1) {
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL7,
                                                 (p<<STV6120_CTRL7_PDIV_SHIFT) |
                                                 ctrl7                         ); /* put back in RCCLKOFF_1 as well */

        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL8,
                                                 (cfhf << STV6120_CTRL8_CFHF_SHIFT) |
                                                 ctrl8                              );
    } else { /* tuner=TUNER_2 */ 
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL16,
                                                 (p<<STV6120_CTRL7_PDIV_SHIFT) |
                                                 ctrl16                        ); /* put back in RCCLKOFF_2 as well */
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL17,
                                                 (cfhf << STV6120_CTRL8_CFHF_SHIFT) |
                                                 ctrl17                             );
    }

    /* if we change the filter re-cal it, and if we change VCO we have to re-cal it, so here goes */
    if (err==ERROR_NONE) err=stv6120_write_reg(tuner==TUNER_1 ? STV6120_STAT1 : STV6120_STAT2,
                                            (STV6120_STAT1_CALVCOSTRT_START << STV6120_STAT1_CALVCOSTRT_SHIFT) | /* start CALVCOSTRT */
                                            STV6120_STAT1_RESERVED                                             );

    /* wait for CALVCOSTRT bit to go low to say VCO cal is finished */
    if (err==ERROR_NONE) {
        timeout=0;
        do {
            err=stv6120_read_reg(tuner==TUNER_1 ? STV6120_STAT1 : STV6120_STAT2, &val);
            timeout++;
        } while ((err==ERROR_NONE) &&
                 (timeout<STV6120_CAL_TIMEOUT) && 
                 ((val & (1<<STV6120_STAT1_CALVCOSTRT_SHIFT))!=(STV6120_STAT1_CALVCOSTRT_FINISHED << STV6120_STAT1_CALVCOSTRT_SHIFT)));
        if ((err==ERROR_NONE) && (timeout==STV6120_CAL_TIMEOUT)) {
            printf("ERROR: tuner wait on CAL timed out\n");
            err=ERROR_TUNER_CAL_TIMEOUT;
        }
    }

    /* wait for LOCK bit to go high to say PLL is locked */
    if (err==ERROR_NONE) {
        timeout=0;
        do {
            err=stv6120_read_reg(tuner==TUNER_1 ? STV6120_STAT1 : STV6120_STAT2, &val);
            timeout++;
        } while ((err==ERROR_NONE) &&
                 (timeout<STV6120_CAL_TIMEOUT) &&
                 ((val & (1<<STV6120_STAT1_LOCK_SHIFT)) != (STV6120_STAT1_LOCK_LOCKED << STV6120_STAT1_LOCK_SHIFT)));
        if ((err==ERROR_NONE) && (timeout==STV6120_CAL_TIMEOUT)) {
            printf("ERROR: tuner wait on lock timed out\n");
            err=ERROR_TUNER_LOCK_TIMEOUT;
        }
    }

    if (err!=ERROR_NONE) printf("ERROR: Tuner set freq %i\n",freq);

    return err;
}

/* -------------------------------------------------------------------------------------------------- */
uint8_t stv6120_init(uint32_t freq_tuner_1, uint32_t freq_tuner_2, bool swap) {
/* -------------------------------------------------------------------------------------------------- */
/* Initialises the tuner. Both tuners can be set up.                                                  */
/*   freq_tuner_1:  0: disable tuner 1                                                                */
/*                 >0: the frequency to set tuner 1 to                                                */
/*   freq_tuner_2:  0: disable tuner 2                                                                */
/*                 >0: the frequency to set tuner 2 to                                                */
/*           swap:  false: use TOP input for tuner_1                                                  */
/*                  true : use bottom input for tuner_1                                               */
/* return: error code                                                                                 */
/* -------------------------------------------------------------------------------------------------- */
    uint8_t err=ERROR_NONE;
    uint8_t k;

    printf("Flow: Tuner init\n");

    /* note, we always init the tuner from scratch so no need to check if we have already inited it before */
    /* also, the tuner doesn't have much of an ID so no point in checking it */

    /* we calculate K from F_xtal/(K+16)=1MHz as specified in the datasheet */
    k=NIM_TUNER_XTAL/1000-16;

    /* setup the clocks for both tuners (note rdiv is a global) */
    if (NIM_TUNER_XTAL>=STV6120_RDIV_THRESHOLD) rdiv=1; /* from the data sheet */
    else rdiv=0;
    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL1,
                         (k                         << STV6120_CTRL1_K_SHIFT)       |
                         (rdiv                      << STV6120_CTRL1_RDIV_SHIFT)    |
                         (STV6120_CTRL1_OSHAPE_SINE << STV6120_CTRL1_OSHAPE_SHIFT)  |
                         (STV6120_CTRL1_MCLKDIV_4   << STV6120_CTRL1_MCLKDIV_SHIFT) );

    /* Configure path 1 */
    if (freq_tuner_1>0) { /* we are go on tuner 1 so turn it on */
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL2,
                             (STV6120_CTRL2_DCLOOPOFF_ENABLE << STV6120_CTRL2_DCLOOPOFF_SHIFT) |
                             (STV6120_CTRL2_SDOFF_OFF        << STV6120_CTRL2_SDOFF_SHIFT)     |
                             (STV6120_CTRL2_SYN_ON           << STV6120_CTRL2_SYN_SHIFT)       |
                             (STV6120_CTRL2_REFOUTSEL_1_25V  << STV6120_CTRL2_REFOUTSEL_SHIFT) |
                             (STV6120_CTRL2_BBGAIN_0DB       << STV6120_CTRL2_BBGAIN_SHIFT)    ); 

        /* CTRL3,4,5,6 are all tuner 1 PLL regs we will set them later */

        /* turn off rcclk for now */
        if (err==ERROR_NONE) {
            ctrl7 = (STV6120_CTRL7_RCCLKOFF_DISABLE << STV6120_CTRL7_RCCLKOFF_SHIFT) |
                    (STV6120_CTRL7_CF_5MHZ          << STV6120_CTRL7_CF_SHIFT)       ; 
            err=stv6120_write_reg(STV6120_CTRL7, ctrl7);
        }

    } else { /* we are not going to use path 1 so shut it down */

        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL2,
                             (STV6120_CTRL2_DCLOOPOFF_DISABLE << STV6120_CTRL2_DCLOOPOFF_SHIFT) |
                             (STV6120_CTRL2_SDOFF_ON          << STV6120_CTRL2_SDOFF_SHIFT)     |
                             (STV6120_CTRL2_SYN_OFF           << STV6120_CTRL2_SYN_SHIFT)       |
                             (STV6120_CTRL2_REFOUTSEL_1_25V   << STV6120_CTRL2_REFOUTSEL_SHIFT) |
                             (STV6120_CTRL2_BBGAIN_0DB        << STV6120_CTRL2_BBGAIN_SHIFT)    );

        /* CTRL3,4,5,6 are all tuner 1 PLL regs we will set them later */

        if (err==ERROR_NONE) {
            ctrl7 = (STV6120_CTRL7_RCCLKOFF_DISABLE << STV6120_CTRL7_RCCLKOFF_SHIFT) |
                    (STV6120_CTRL7_CF_5MHZ          << STV6120_CTRL7_CF_SHIFT)       ;
            err=stv6120_write_reg(STV6120_CTRL7, ctrl7);
        }
    }

    /* we need to set tcal for both tuners, but we need to remember the state in case we are using tuner 1 later */
    if (err==ERROR_NONE) {
        ctrl8 = (STV6120_CTRL8_TCAL_DIV_2    << STV6120_CTRL8_TCAL_SHIFT) | 
                (STV6120_CTRL8_CALTIME_500US << STV6120_CTRL8_TCAL_SHIFT) ; 
        err=stv6120_write_reg(STV6120_CTRL8, ctrl8);
    }

    /* no need to touch the STAT1 status register for now */

    /* setup the RF path registers. RFA and RFD are not used. RFB is fed from the TOP NIM input, RFC from the BOTTOM */
    /* if we are swapping these inputs over we need to enable the correct LNAs */
    if (swap) {
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL9,
                     (STV6120_CTRL9_RFSEL_RFC_IN << STV6120_CTRL9_RFSEL_1_SHIFT)  |
                     (STV6120_CTRL9_RFSEL_RFB_IN << STV6120_CTRL9_RFSEL_2_SHIFT)  |
                     STV6120_CTRL9_RESERVED );
        /* decide on which LNAs are we going to enable */
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL10,
                     ((                                            STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNADON_SHIFT)   |
                     ((freq_tuner_2 > 0 ? STV6120_CTRL10_LNA_ON  : STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNABON_SHIFT)   |
                     ((freq_tuner_1 > 0 ? STV6120_CTRL10_LNA_ON  : STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNACON_SHIFT)   |
                     ((                                            STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNAAON_SHIFT)   |
                     ((freq_tuner_2 > 0 ? STV6120_CTRL10_PATH_ON : STV6120_CTRL10_PATH_OFF) << STV6120_CTRL10_PATHON_2_SHIFT) |
                     ((freq_tuner_1 > 0 ? STV6120_CTRL10_PATH_ON : STV6120_CTRL10_PATH_OFF) << STV6120_CTRL10_PATHON_1_SHIFT) );

    } else {
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL9,
                     (STV6120_CTRL9_RFSEL_RFB_IN << STV6120_CTRL9_RFSEL_1_SHIFT)  |
                     (STV6120_CTRL9_RFSEL_RFC_IN << STV6120_CTRL9_RFSEL_2_SHIFT)  |
                     STV6120_CTRL9_RESERVED );
        /* decide on which LNAs are we going to enable */
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL10,
                     ((                                            STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNADON_SHIFT)   |
                     ((freq_tuner_2 > 0 ? STV6120_CTRL10_LNA_ON  : STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNACON_SHIFT)   |
                     ((freq_tuner_1 > 0 ? STV6120_CTRL10_LNA_ON  : STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNABON_SHIFT)   |
                     ((                                            STV6120_CTRL10_LNA_OFF)  << STV6120_CTRL10_LNAAON_SHIFT)   |
                     ((freq_tuner_2 > 0 ? STV6120_CTRL10_PATH_ON : STV6120_CTRL10_PATH_OFF) << STV6120_CTRL10_PATHON_2_SHIFT) |
                     ((freq_tuner_1 > 0 ? STV6120_CTRL10_PATH_ON : STV6120_CTRL10_PATH_OFF) << STV6120_CTRL10_PATHON_1_SHIFT) );
    }

    /* Configure path 2 */
    if (freq_tuner_2>0) { /* we are go on tuner 2 so turn it on */
        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL11, 
                             (STV6120_CTRL2_DCLOOPOFF_ENABLE << STV6120_CTRL2_DCLOOPOFF_SHIFT) |
                             (STV6120_CTRL2_SDOFF_OFF        << STV6120_CTRL2_SDOFF_SHIFT)     |
                             (STV6120_CTRL2_SYN_ON           << STV6120_CTRL2_SYN_SHIFT)       |
                             (STV6120_CTRL2_REFOUTSEL_1_25V  << STV6120_CTRL2_REFOUTSEL_SHIFT) |
                             (STV6120_CTRL2_BBGAIN_6DB       << STV6120_CTRL2_BBGAIN_SHIFT)    );

        /* CTRL12, 13, 14, 15 are PLL for tuner 2 */

        if (err==ERROR_NONE) {
            ctrl16 = (STV6120_CTRL7_RCCLKOFF_ENABLE << STV6120_CTRL7_RCCLKOFF_SHIFT) |
                     (STV6120_CTRL7_CF_5MHZ         << STV6120_CTRL7_CF_SHIFT)        ;
            err=stv6120_write_reg(STV6120_CTRL16, ctrl16);
        }

    } else { /* we are not going to use path 1 so shut it down */

        if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL11,
                             (STV6120_CTRL2_DCLOOPOFF_DISABLE << STV6120_CTRL2_DCLOOPOFF_SHIFT) |
                             (STV6120_CTRL2_SDOFF_ON          << STV6120_CTRL2_SDOFF_SHIFT)     |
                             (STV6120_CTRL2_SYN_OFF           << STV6120_CTRL2_SYN_SHIFT)       |
                             (STV6120_CTRL2_REFOUTSEL_1_25V   << STV6120_CTRL2_REFOUTSEL_SHIFT) |
                             (STV6120_CTRL2_BBGAIN_0DB        << STV6120_CTRL2_BBGAIN_SHIFT)    );

        /* CTRL12, 13, 14, 15 are PLL for tuner 2 */

        if (err==ERROR_NONE) {
            ctrl16 = (STV6120_CTRL7_RCCLKOFF_DISABLE << STV6120_CTRL7_RCCLKOFF_SHIFT) |
                     (STV6120_CTRL7_CF_5MHZ          << STV6120_CTRL7_CF_SHIFT)       ;
            err=stv6120_write_reg(STV6120_CTRL16, ctrl16);
        }
    }

    /* there is no tcal field in CTRL17 but we still need to remember the state in case we are using tuner 2 later */
    if (err==ERROR_NONE) {
        ctrl17 = (STV6120_CTRL8_CALTIME_500US << STV6120_CTRL8_TCAL_SHIFT); 
        err=stv6120_write_reg(STV6120_CTRL17, ctrl8);
    }

    /* no need to touch the STAT2 status register for now */

    /* CTRL18, CTRL19 are test regs so just write in the default */
    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL18,STV6120_CTRL18_DEFAULT);
    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL19,STV6120_CTRL19_DEFAULT);

    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL20,
                         (STV6120_CTRL20_VCOAMP_NORMAL << STV6120_CTRL20_VCOAMP_SHIFT) |
                         STV6120_CTRL20_RESERVED                                       );

    /* CTRL21, CTRL22 are test regs so leave alone */
    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL21,STV6120_CTRL21_DEFAULT);
    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL22,STV6120_CTRL22_DEFAULT);

    if (err==ERROR_NONE) err=stv6120_write_reg(STV6120_CTRL23,
                         (STV6120_CTRL20_VCOAMP_NORMAL << STV6120_CTRL20_VCOAMP_SHIFT) |
                         STV6120_CTRL20_RESERVED                                       );

    /* now we can calibrate the lowpass filters and setup the PLLs for each tuner required */
    if ((err==ERROR_NONE) && (freq_tuner_1>0)) {
        err=stv6120_cal_lowpass(TUNER_1);
        if (err==ERROR_NONE) err=stv6120_set_freq(TUNER_1, freq_tuner_1);
    }
    if ((err==ERROR_NONE) && (freq_tuner_2>0)) {
        err=stv6120_cal_lowpass(TUNER_2);
        if (err==ERROR_NONE) err=stv6120_set_freq(TUNER_2, freq_tuner_2);
    }

    if (err!=ERROR_NONE) printf("ERROR: Failed to init Tuner %i, %i\n",freq_tuner_1, freq_tuner_2);

    return err;
}




/* -------------------------------------------------------------------------------------------------- */
void stv6120_print_settings() {
/* -------------------------------------------------------------------------------------------------- */
/* debug routine to print out all the regsiter values in the tuner                                    */
/* -------------------------------------------------------------------------------------------------- */
    uint8_t val;

    printf("Tuner regs are:\n");
    for(int i=0;i<0x19;i++) {
        stv6120_read_reg(i,&val);
        printf(" 0x%.2x = 0x%.2x\n",i,val);
    }
}