cx24123.c

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/*
 *   Conexant cx24123/cx24109 - DVB QPSK Satellite demod/tuner driver
 *
 *   Copyright (C) 2005 Steven Toth <[email protected]>
 *
 *   Support for KWorld DVB-S 100 by Vadim Catana <[email protected]>
 *
 *   Support for CX24123/CX24113-NIM by Patrick Boettcher <[email protected]>
 *
 *   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 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, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>

#include "dvb_frontend.h"
#include "cx24123.h"

#define XTAL 10111000

static int force_band;
module_param(force_band, int, 0644);
MODULE_PARM_DESC(force_band, "Force a specific band select "\
    "(1-9, default:off).");

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Activates frontend debugging (default:0)");

#define info(args...) do { printk(KERN_INFO "CX24123: " args); } while (0)
#define err(args...)  do { printk(KERN_ERR  "CX24123: " args); } while (0)

#define dprintk(args...) \
    do { \
        if (debug) { \
            printk(KERN_DEBUG "CX24123: %s: ", __func__); \
            printk(args); \
        } \
    } while (0)

struct cx24123_state {
    struct i2c_adapter *i2c;
    const struct cx24123_config *config;

    struct dvb_frontend frontend;

    /* Some PLL specifics for tuning */
    u32 VCAarg;
    u32 VGAarg;
    u32 bandselectarg;
    u32 pllarg;
    u32 FILTune;

    struct i2c_adapter tuner_i2c_adapter;

    u8 demod_rev;

    /* The Demod/Tuner can't easily provide these, we cache them */
    u32 currentfreq;
    u32 currentsymbolrate;
};

/* Various tuner defaults need to be established for a given symbol rate Sps */
static struct cx24123_AGC_val {
    u32 symbolrate_low;
    u32 symbolrate_high;
    u32 VCAprogdata;
    u32 VGAprogdata;
    u32 FILTune;
} cx24123_AGC_vals[] =
{
    {
        .symbolrate_low     = 1000000,
        .symbolrate_high    = 4999999,
        /* the specs recommend other values for VGA offsets,
           but tests show they are wrong */
        .VGAprogdata        = (1 << 19) | (0x180 << 9) | 0x1e0,
        .VCAprogdata        = (2 << 19) | (0x07 << 9) | 0x07,
        .FILTune        = 0x27f /* 0.41 V */
    },
    {
        .symbolrate_low     =  5000000,
        .symbolrate_high    = 14999999,
        .VGAprogdata        = (1 << 19) | (0x180 << 9) | 0x1e0,
        .VCAprogdata        = (2 << 19) | (0x07 << 9) | 0x1f,
        .FILTune        = 0x317 /* 0.90 V */
    },
    {
        .symbolrate_low     = 15000000,
        .symbolrate_high    = 45000000,
        .VGAprogdata        = (1 << 19) | (0x100 << 9) | 0x180,
        .VCAprogdata        = (2 << 19) | (0x07 << 9) | 0x3f,
        .FILTune        = 0x145 /* 2.70 V */
    },
};

/*
 * Various tuner defaults need to be established for a given frequency kHz.
 * fixme: The bounds on the bands do not match the doc in real life.
 * fixme: Some of them have been moved, other might need adjustment.
 */
static struct cx24123_bandselect_val {
    u32 freq_low;
    u32 freq_high;
    u32 VCOdivider;
    u32 progdata;
} cx24123_bandselect_vals[] =
{
    /* band 1 */
    {
        .freq_low   = 950000,
        .freq_high  = 1074999,
        .VCOdivider = 4,
        .progdata   = (0 << 19) | (0 << 9) | 0x40,
    },

    /* band 2 */
    {
        .freq_low   = 1075000,
        .freq_high  = 1177999,
        .VCOdivider = 4,
        .progdata   = (0 << 19) | (0 << 9) | 0x80,
    },

    /* band 3 */
    {
        .freq_low   = 1178000,
        .freq_high  = 1295999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x01,
    },

    /* band 4 */
    {
        .freq_low   = 1296000,
        .freq_high  = 1431999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x02,
    },

    /* band 5 */
    {
        .freq_low   = 1432000,
        .freq_high  = 1575999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x04,
    },

    /* band 6 */
    {
        .freq_low   = 1576000,
        .freq_high  = 1717999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x08,
    },

    /* band 7 */
    {
        .freq_low   = 1718000,
        .freq_high  = 1855999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x10,
    },

    /* band 8 */
    {
        .freq_low   = 1856000,
        .freq_high  = 2035999,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x20,
    },

    /* band 9 */
    {
        .freq_low   = 2036000,
        .freq_high  = 2150000,
        .VCOdivider = 2,
        .progdata   = (0 << 19) | (1 << 9) | 0x40,
    },
};

static struct {
    u8 reg;
    u8 data;
} cx24123_regdata[] =
{
    {0x00, 0x03}, /* Reset system */
    {0x00, 0x00}, /* Clear reset */
    {0x03, 0x07}, /* QPSK, DVB, Auto Acquisition (default) */
    {0x04, 0x10}, /* MPEG */
    {0x05, 0x04}, /* MPEG */
    {0x06, 0x31}, /* MPEG (default) */
    {0x0b, 0x00}, /* Freq search start point (default) */
    {0x0c, 0x00}, /* Demodulator sample gain (default) */
    {0x0d, 0x7f}, /* Force driver to shift until the maximum (+-10 MHz) */
    {0x0e, 0x03}, /* Default non-inverted, FEC 3/4 (default) */
    {0x0f, 0xfe}, /* FEC search mask (all supported codes) */
    {0x10, 0x01}, /* Default search inversion, no repeat (default) */
    {0x16, 0x00}, /* Enable reading of frequency */
    {0x17, 0x01}, /* Enable EsNO Ready Counter */
    {0x1c, 0x80}, /* Enable error counter */
    {0x20, 0x00}, /* Tuner burst clock rate = 500KHz */
    {0x21, 0x15}, /* Tuner burst mode, word length = 0x15 */
    {0x28, 0x00}, /* Enable FILTERV with positive pol., DiSEqC 2.x off */
    {0x29, 0x00}, /* DiSEqC LNB_DC off */
    {0x2a, 0xb0}, /* DiSEqC Parameters (default) */
    {0x2b, 0x73}, /* DiSEqC Tone Frequency (default) */
    {0x2c, 0x00}, /* DiSEqC Message (0x2c - 0x31) */
    {0x2d, 0x00},
    {0x2e, 0x00},
    {0x2f, 0x00},
    {0x30, 0x00},
    {0x31, 0x00},
    {0x32, 0x8c}, /* DiSEqC Parameters (default) */
    {0x33, 0x00}, /* Interrupts off (0x33 - 0x34) */
    {0x34, 0x00},
    {0x35, 0x03}, /* DiSEqC Tone Amplitude (default) */
    {0x36, 0x02}, /* DiSEqC Parameters (default) */
    {0x37, 0x3a}, /* DiSEqC Parameters (default) */
    {0x3a, 0x00}, /* Enable AGC accumulator (for signal strength) */
    {0x44, 0x00}, /* Constellation (default) */
    {0x45, 0x00}, /* Symbol count (default) */
    {0x46, 0x0d}, /* Symbol rate estimator on (default) */
    {0x56, 0xc1}, /* Error Counter = Viterbi BER */
    {0x57, 0xff}, /* Error Counter Window (default) */
    {0x5c, 0x20}, /* Acquisition AFC Expiration window (default is 0x10) */
    {0x67, 0x83}, /* Non-DCII symbol clock */
};

static int cx24123_i2c_writereg(struct cx24123_state *state,
    u8 i2c_addr, int reg, int data)
{
    u8 buf[] = { reg, data };
    struct i2c_msg msg = {
        .addr = i2c_addr, .flags = 0, .buf = buf, .len = 2
    };
    int err;

    /* printk(KERN_DEBUG "wr(%02x): %02x %02x\n", i2c_addr, reg, data); */

    err = i2c_transfer(state->i2c, &msg, 1);
    if (err != 1) {
        printk("%s: writereg error(err == %i, reg == 0x%02x,"
             " data == 0x%02x)\n", __func__, err, reg, data);
        return err;
    }

    return 0;
}

static int cx24123_i2c_readreg(struct cx24123_state *state, u8 i2c_addr, u8 reg)
{
    int ret;
    u8 b = 0;
    struct i2c_msg msg[] = {
        { .addr = i2c_addr, .flags = 0, .buf = &reg, .len = 1 },
        { .addr = i2c_addr, .flags = I2C_M_RD, .buf = &b, .len = 1 }
    };

    ret = i2c_transfer(state->i2c, msg, 2);

    if (ret != 2) {
        err("%s: reg=0x%x (error=%d)\n", __func__, reg, ret);
        return ret;
    }

    /* printk(KERN_DEBUG "rd(%02x): %02x %02x\n", i2c_addr, reg, b); */

    return b;
}

#define cx24123_readreg(state, reg) \
    cx24123_i2c_readreg(state, state->config->demod_address, reg)
#define cx24123_writereg(state, reg, val) \
    cx24123_i2c_writereg(state, state->config->demod_address, reg, val)

static int cx24123_set_inversion(struct cx24123_state *state,
    fe_spectral_inversion_t inversion)
{
    u8 nom_reg = cx24123_readreg(state, 0x0e);
    u8 auto_reg = cx24123_readreg(state, 0x10);

    switch (inversion) {
    case INVERSION_OFF:
        dprintk("inversion off\n");
        cx24123_writereg(state, 0x0e, nom_reg & ~0x80);
        cx24123_writereg(state, 0x10, auto_reg | 0x80);
        break;
    case INVERSION_ON:
        dprintk("inversion on\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x80);
        cx24123_writereg(state, 0x10, auto_reg | 0x80);
        break;
    case INVERSION_AUTO:
        dprintk("inversion auto\n");
        cx24123_writereg(state, 0x10, auto_reg & ~0x80);
        break;
    default:
        return -EINVAL;
    }

    return 0;
}

static int cx24123_get_inversion(struct cx24123_state *state,
    fe_spectral_inversion_t *inversion)
{
    u8 val;

    val = cx24123_readreg(state, 0x1b) >> 7;

    if (val == 0) {
        dprintk("read inversion off\n");
        *inversion = INVERSION_OFF;
    } else {
        dprintk("read inversion on\n");
        *inversion = INVERSION_ON;
    }

    return 0;
}

static int cx24123_set_fec(struct cx24123_state *state, fe_code_rate_t fec)
{
    u8 nom_reg = cx24123_readreg(state, 0x0e) & ~0x07;

    if ((fec < FEC_NONE) || (fec > FEC_AUTO))
        fec = FEC_AUTO;

    /* Set the soft decision threshold */
    if (fec == FEC_1_2)
        cx24123_writereg(state, 0x43,
            cx24123_readreg(state, 0x43) | 0x01);
    else
        cx24123_writereg(state, 0x43,
            cx24123_readreg(state, 0x43) & ~0x01);

    switch (fec) {
    case FEC_1_2:
        dprintk("set FEC to 1/2\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x01);
        cx24123_writereg(state, 0x0f, 0x02);
        break;
    case FEC_2_3:
        dprintk("set FEC to 2/3\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x02);
        cx24123_writereg(state, 0x0f, 0x04);
        break;
    case FEC_3_4:
        dprintk("set FEC to 3/4\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x03);
        cx24123_writereg(state, 0x0f, 0x08);
        break;
    case FEC_4_5:
        dprintk("set FEC to 4/5\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x04);
        cx24123_writereg(state, 0x0f, 0x10);
        break;
    case FEC_5_6:
        dprintk("set FEC to 5/6\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x05);
        cx24123_writereg(state, 0x0f, 0x20);
        break;
    case FEC_6_7:
        dprintk("set FEC to 6/7\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x06);
        cx24123_writereg(state, 0x0f, 0x40);
        break;
    case FEC_7_8:
        dprintk("set FEC to 7/8\n");
        cx24123_writereg(state, 0x0e, nom_reg | 0x07);
        cx24123_writereg(state, 0x0f, 0x80);
        break;
    case FEC_AUTO:
        dprintk("set FEC to auto\n");
        cx24123_writereg(state, 0x0f, 0xfe);
        break;
    default:
        return -EOPNOTSUPP;
    }

    return 0;
}

static int cx24123_get_fec(struct cx24123_state *state, fe_code_rate_t *fec)
{
    int ret;

    ret = cx24123_readreg(state, 0x1b);
    if (ret < 0)
        return ret;
    ret = ret & 0x07;

    switch (ret) {
    case 1:
        *fec = FEC_1_2;
        break;
    case 2:
        *fec = FEC_2_3;
        break;
    case 3:
        *fec = FEC_3_4;
        break;
    case 4:
        *fec = FEC_4_5;
        break;
    case 5:
        *fec = FEC_5_6;
        break;
    case 6:
        *fec = FEC_6_7;
        break;
    case 7:
        *fec = FEC_7_8;
        break;
    default:
        /* this can happen when there's no lock */
        *fec = FEC_NONE;
    }

    return 0;
}

/* Approximation of closest integer of log2(a/b). It actually gives the
   lowest integer i such that 2^i >= round(a/b) */
static u32 cx24123_int_log2(u32 a, u32 b)
{
    u32 exp, nearest = 0;
    u32 div = a / b;
    if (a % b >= b / 2)
        ++div;
    if (div < (1 << 31)) {
        for (exp = 1; div > exp; nearest++)
            exp += exp;
    }
    return nearest;
}

static int cx24123_set_symbolrate(struct cx24123_state *state, u32 srate)
{
    u32 tmp, sample_rate, ratio, sample_gain;
    u8 pll_mult;

    /*  check if symbol rate is within limits */
    if ((srate > state->frontend.ops.info.symbol_rate_max) ||
        (srate < state->frontend.ops.info.symbol_rate_min))
        return -EOPNOTSUPP;

    /* choose the sampling rate high enough for the required operation,
       while optimizing the power consumed by the demodulator */
    if (srate < (XTAL*2)/2)
        pll_mult = 2;
    else if (srate < (XTAL*3)/2)
        pll_mult = 3;
    else if (srate < (XTAL*4)/2)
        pll_mult = 4;
    else if (srate < (XTAL*5)/2)
        pll_mult = 5;
    else if (srate < (XTAL*6)/2)
        pll_mult = 6;
    else if (srate < (XTAL*7)/2)
        pll_mult = 7;
    else if (srate < (XTAL*8)/2)
        pll_mult = 8;
    else
        pll_mult = 9;


    sample_rate = pll_mult * XTAL;

    /*
        SYSSymbolRate[21:0] = (srate << 23) / sample_rate

        We have to use 32 bit unsigned arithmetic without precision loss.
        The maximum srate is 45000000 or 0x02AEA540. This number has
        only 6 clear bits on top, hence we can shift it left only 6 bits
        at a time. Borrowed from cx24110.c
    */

    tmp = srate << 6;
    ratio = tmp / sample_rate;

    tmp = (tmp % sample_rate) << 6;
    ratio = (ratio << 6) + (tmp / sample_rate);

    tmp = (tmp % sample_rate) << 6;
    ratio = (ratio << 6) + (tmp / sample_rate);

    tmp = (tmp % sample_rate) << 5;
    ratio = (ratio << 5) + (tmp / sample_rate);


    cx24123_writereg(state, 0x01, pll_mult * 6);

    cx24123_writereg(state, 0x08, (ratio >> 16) & 0x3f);
    cx24123_writereg(state, 0x09, (ratio >> 8) & 0xff);
    cx24123_writereg(state, 0x0a, ratio & 0xff);

    /* also set the demodulator sample gain */
    sample_gain = cx24123_int_log2(sample_rate, srate);
    tmp = cx24123_readreg(state, 0x0c) & ~0xe0;
    cx24123_writereg(state, 0x0c, tmp | sample_gain << 5);

    dprintk("srate=%d, ratio=0x%08x, sample_rate=%i sample_gain=%d\n",
        srate, ratio, sample_rate, sample_gain);

    return 0;
}

/*
 * Based on the required frequency and symbolrate, the tuner AGC has
 * to be configured and the correct band selected.
 * Calculate those values.
 */
static int cx24123_pll_calculate(struct dvb_frontend *fe)
{
    struct dtv_frontend_properties *p = &fe->dtv_property_cache;
    struct cx24123_state *state = fe->demodulator_priv;
    u32 ndiv = 0, adiv = 0, vco_div = 0;
    int i = 0;
    int pump = 2;
    int band = 0;
    int num_bands = ARRAY_SIZE(cx24123_bandselect_vals);
    struct cx24123_bandselect_val *bsv = NULL;
    struct cx24123_AGC_val *agcv = NULL;

    /* Defaults for low freq, low rate */
    state->VCAarg = cx24123_AGC_vals[0].VCAprogdata;
    state->VGAarg = cx24123_AGC_vals[0].VGAprogdata;
    state->bandselectarg = cx24123_bandselect_vals[0].progdata;
    vco_div = cx24123_bandselect_vals[0].VCOdivider;

    /* For the given symbol rate, determine the VCA, VGA and
     * FILTUNE programming bits */
    for (i = 0; i < ARRAY_SIZE(cx24123_AGC_vals); i++) {
        agcv = &cx24123_AGC_vals[i];
        if ((agcv->symbolrate_low <= p->symbol_rate) &&
            (agcv->symbolrate_high >= p->symbol_rate)) {
            state->VCAarg = agcv->VCAprogdata;
            state->VGAarg = agcv->VGAprogdata;
            state->FILTune = agcv->FILTune;
        }
    }

    /* determine the band to use */
    if (force_band < 1 || force_band > num_bands) {
        for (i = 0; i < num_bands; i++) {
            bsv = &cx24123_bandselect_vals[i];
            if ((bsv->freq_low <= p->frequency) &&
                (bsv->freq_high >= p->frequency))
                band = i;
        }
    } else
        band = force_band - 1;

    state->bandselectarg = cx24123_bandselect_vals[band].progdata;
    vco_div = cx24123_bandselect_vals[band].VCOdivider;

    /* determine the charge pump current */
    if (p->frequency < (cx24123_bandselect_vals[band].freq_low +
        cx24123_bandselect_vals[band].freq_high) / 2)
        pump = 0x01;
    else
        pump = 0x02;

    /* Determine the N/A dividers for the requested lband freq (in kHz). */
    /* Note: the reference divider R=10, frequency is in KHz,
     * XTAL is in Hz */
    ndiv = (((p->frequency * vco_div * 10) /
        (2 * XTAL / 1000)) / 32) & 0x1ff;
    adiv = (((p->frequency * vco_div * 10) /
        (2 * XTAL / 1000)) % 32) & 0x1f;

    if (adiv == 0 && ndiv > 0)
        ndiv--;

    /* control bits 11, refdiv 11, charge pump polarity 1,
     * charge pump current, ndiv, adiv */
    state->pllarg = (3 << 19) | (3 << 17) | (1 << 16) |
        (pump << 14) | (ndiv << 5) | adiv;

    return 0;
}

/*
 * Tuner data is 21 bits long, must be left-aligned in data.
 * Tuner cx24109 is written through a dedicated 3wire interface
 * on the demod chip.
 */
static int cx24123_pll_writereg(struct dvb_frontend *fe, u32 data)
{
    struct cx24123_state *state = fe->demodulator_priv;
    unsigned long timeout;

    dprintk("pll writereg called, data=0x%08x\n", data);

    /* align the 21 bytes into to bit23 boundary */
    data = data << 3;

    /* Reset the demod pll word length to 0x15 bits */
    cx24123_writereg(state, 0x21, 0x15);

    /* write the msb 8 bits, wait for the send to be completed */
    timeout = jiffies + msecs_to_jiffies(40);
    cx24123_writereg(state, 0x22, (data >> 16) & 0xff);
    while ((cx24123_readreg(state, 0x20) & 0x40) == 0) {
        if (time_after(jiffies, timeout)) {
            err("%s:  demodulator is not responding, "\
                "possibly hung, aborting.\n", __func__);
            return -EREMOTEIO;
        }
        msleep(10);
    }

    /* send another 8 bytes, wait for the send to be completed */
    timeout = jiffies + msecs_to_jiffies(40);
    cx24123_writereg(state, 0x22, (data >> 8) & 0xff);
    while ((cx24123_readreg(state, 0x20) & 0x40) == 0) {
        if (time_after(jiffies, timeout)) {
            err("%s:  demodulator is not responding, "\
                "possibly hung, aborting.\n", __func__);
            return -EREMOTEIO;
        }
        msleep(10);
    }

    /* send the lower 5 bits of this byte, padded with 3 LBB,
     * wait for the send to be completed */
    timeout = jiffies + msecs_to_jiffies(40);
    cx24123_writereg(state, 0x22, (data) & 0xff);
    while ((cx24123_readreg(state, 0x20) & 0x80)) {
        if (time_after(jiffies, timeout)) {
            err("%s:  demodulator is not responding," \
                "possibly hung, aborting.\n", __func__);
            return -EREMOTEIO;
        }
        msleep(10);
    }

    /* Trigger the demod to configure the tuner */
    cx24123_writereg(state, 0x20, cx24123_readreg(state, 0x20) | 2);
    cx24123_writereg(state, 0x20, cx24123_readreg(state, 0x20) & 0xfd);

    return 0;
}

static int cx24123_pll_tune(struct dvb_frontend *fe)
{
    struct dtv_frontend_properties *p = &fe->dtv_property_cache;
    struct cx24123_state *state = fe->demodulator_priv;
    u8 val;

    dprintk("frequency=%i\n", p->frequency);

    if (cx24123_pll_calculate(fe) != 0) {
        err("%s: cx24123_pll_calcutate failed\n", __func__);
        return -EINVAL;
    }

    /* Write the new VCO/VGA */
    cx24123_pll_writereg(fe, state->VCAarg);
    cx24123_pll_writereg(fe, state->VGAarg);

    /* Write the new bandselect and pll args */
    cx24123_pll_writereg(fe, state->bandselectarg);
    cx24123_pll_writereg(fe, state->pllarg);

    /* set the FILTUNE voltage */
    val = cx24123_readreg(state, 0x28) & ~0x3;
    cx24123_writereg(state, 0x27, state->FILTune >> 2);
    cx24123_writereg(state, 0x28, val | (state->FILTune & 0x3));

    dprintk("pll tune VCA=%d, band=%d, pll=%d\n", state->VCAarg,
            state->bandselectarg, state->pllarg);

    return 0;
}


/*
 * 0x23:
 *    [7:7] = BTI enabled
 *    [6:6] = I2C repeater enabled
 *    [5:5] = I2C repeater start
 *    [0:0] = BTI start
 */

/* mode == 1 -> i2c-repeater, 0 -> bti */
static int cx24123_repeater_mode(struct cx24123_state *state, u8 mode, u8 start)
{
    u8 r = cx24123_readreg(state, 0x23) & 0x1e;
    if (mode)
        r |= (1 << 6) | (start << 5);
    else
        r |= (1 << 7) | (start);
    return cx24123_writereg(state, 0x23, r);
}

static int cx24123_initfe(struct dvb_frontend *fe)
{
    struct cx24123_state *state = fe->demodulator_priv;
    int i;

    dprintk("init frontend\n");

    /* Configure the demod to a good set of defaults */
    for (i = 0; i < ARRAY_SIZE(cx24123_regdata); i++)
        cx24123_writereg(state, cx24123_regdata[i].reg,
            cx24123_regdata[i].data);

    /* Set the LNB polarity */
    if (state->config->lnb_polarity)
        cx24123_writereg(state, 0x32,
            cx24123_readreg(state, 0x32) | 0x02);

    if (state->config->dont_use_pll)
        cx24123_repeater_mode(state, 1, 0);

    return 0;
}

static int cx24123_set_voltage(struct dvb_frontend *fe,
    fe_sec_voltage_t voltage)
{
    struct cx24123_state *state = fe->demodulator_priv;
    u8 val;

    val = cx24123_readreg(state, 0x29) & ~0x40;

    switch (voltage) {
    case SEC_VOLTAGE_13:
        dprintk("setting voltage 13V\n");
        return cx24123_writereg(state, 0x29, val & 0x7f);
    case SEC_VOLTAGE_18:
        dprintk("setting voltage 18V\n");
        return cx24123_writereg(state, 0x29, val | 0x80);
    case SEC_VOLTAGE_OFF:
        /* already handled in cx88-dvb */
        return 0;
    default:
        return -EINVAL;
    };

    return 0;
}

/* wait for diseqc queue to become ready (or timeout) */
static void cx24123_wait_for_diseqc(struct cx24123_state *state)
{
    unsigned long timeout = jiffies + msecs_to_jiffies(200);
    while (!(cx24123_readreg(state, 0x29) & 0x40)) {
        if (time_after(jiffies, timeout)) {
            err("%s: diseqc queue not ready, " \
                "command may be lost.\n", __func__);
            break;
        }
        msleep(10);
    }
}

static int cx24123_send_diseqc_msg(struct dvb_frontend *fe,
    struct dvb_diseqc_master_cmd *cmd)
{
    struct cx24123_state *state = fe->demodulator_priv;
    int i, val, tone;

    dprintk("\n");

    /* stop continuous tone if enabled */
    tone = cx24123_readreg(state, 0x29);
    if (tone & 0x10)
        cx24123_writereg(state, 0x29, tone & ~0x50);

    /* wait for diseqc queue ready */
    cx24123_wait_for_diseqc(state);

    /* select tone mode */
    cx24123_writereg(state, 0x2a, cx24123_readreg(state, 0x2a) & 0xfb);

    for (i = 0; i < cmd->msg_len; i++)
        cx24123_writereg(state, 0x2C + i, cmd->msg[i]);

    val = cx24123_readreg(state, 0x29);
    cx24123_writereg(state, 0x29, ((val & 0x90) | 0x40) |
        ((cmd->msg_len-3) & 3));

    /* wait for diseqc message to finish sending */
    cx24123_wait_for_diseqc(state);

    /* restart continuous tone if enabled */
    if (tone & 0x10)
        cx24123_writereg(state, 0x29, tone & ~0x40);

    return 0;
}

static int cx24123_diseqc_send_burst(struct dvb_frontend *fe,
    fe_sec_mini_cmd_t burst)
{
    struct cx24123_state *state = fe->demodulator_priv;
    int val, tone;

    dprintk("\n");

    /* stop continuous tone if enabled */
    tone = cx24123_readreg(state, 0x29);
    if (tone & 0x10)
        cx24123_writereg(state, 0x29, tone & ~0x50);

    /* wait for diseqc queue ready */
    cx24123_wait_for_diseqc(state);

    /* select tone mode */
    cx24123_writereg(state, 0x2a, cx24123_readreg(state, 0x2a) | 0x4);
    msleep(30);
    val = cx24123_readreg(state, 0x29);
    if (burst == SEC_MINI_A)
        cx24123_writereg(state, 0x29, ((val & 0x90) | 0x40 | 0x00));
    else if (burst == SEC_MINI_B)
        cx24123_writereg(state, 0x29, ((val & 0x90) | 0x40 | 0x08));
    else
        return -EINVAL;

    cx24123_wait_for_diseqc(state);
    cx24123_writereg(state, 0x2a, cx24123_readreg(state, 0x2a) & 0xfb);

    /* restart continuous tone if enabled */
    if (tone & 0x10)
        cx24123_writereg(state, 0x29, tone & ~0x40);

    return 0;
}

static int cx24123_read_status(struct dvb_frontend *fe, fe_status_t *status)
{
    struct cx24123_state *state = fe->demodulator_priv;
    int sync = cx24123_readreg(state, 0x14);

    *status = 0;
    if (state->config->dont_use_pll) {
        u32 tun_status = 0;
        if (fe->ops.tuner_ops.get_status)
            fe->ops.tuner_ops.get_status(fe, &tun_status);
        if (tun_status & TUNER_STATUS_LOCKED)
            *status |= FE_HAS_SIGNAL;
    } else {
        int lock = cx24123_readreg(state, 0x20);
        if (lock & 0x01)
            *status |= FE_HAS_SIGNAL;
    }

    if (sync & 0x02)
        *status |= FE_HAS_CARRIER;  /* Phase locked */
    if (sync & 0x04)
        *status |= FE_HAS_VITERBI;

    /* Reed-Solomon Status */
    if (sync & 0x08)
        *status |= FE_HAS_SYNC;
    if (sync & 0x80)
        *status |= FE_HAS_LOCK;     /*Full Sync */

    return 0;
}

/*
 * Configured to return the measurement of errors in blocks,
 * because no UCBLOCKS value is available, so this value doubles up
 * to satisfy both measurements.
 */
static int cx24123_read_ber(struct dvb_frontend *fe, u32 *ber)
{
    struct cx24123_state *state = fe->demodulator_priv;

    /* The true bit error rate is this value divided by
       the window size (set as 256 * 255) */
    *ber = ((cx24123_readreg(state, 0x1c) & 0x3f) << 16) |
        (cx24123_readreg(state, 0x1d) << 8 |
         cx24123_readreg(state, 0x1e));

    dprintk("BER = %d\n", *ber);

    return 0;
}

static int cx24123_read_signal_strength(struct dvb_frontend *fe,
    u16 *signal_strength)
{
    struct cx24123_state *state = fe->demodulator_priv;

    /* larger = better */
    *signal_strength = cx24123_readreg(state, 0x3b) << 8;

    dprintk("Signal strength = %d\n", *signal_strength);

    return 0;
}

static int cx24123_read_snr(struct dvb_frontend *fe, u16 *snr)
{
    struct cx24123_state *state = fe->demodulator_priv;

    /* Inverted raw Es/N0 count, totally bogus but better than the
       BER threshold. */
    *snr = 65535 - (((u16)cx24123_readreg(state, 0x18) << 8) |
             (u16)cx24123_readreg(state, 0x19));

    dprintk("read S/N index = %d\n", *snr);

    return 0;
}

static int cx24123_set_frontend(struct dvb_frontend *fe)
{
    struct cx24123_state *state = fe->demodulator_priv;
    struct dtv_frontend_properties *p = &fe->dtv_property_cache;

    dprintk("\n");

    if (state->config->set_ts_params)
        state->config->set_ts_params(fe, 0);

    state->currentfreq = p->frequency;
    state->currentsymbolrate = p->symbol_rate;

    cx24123_set_inversion(state, p->inversion);
    cx24123_set_fec(state, p->fec_inner);
    cx24123_set_symbolrate(state, p->symbol_rate);

    if (!state->config->dont_use_pll)
        cx24123_pll_tune(fe);
    else if (fe->ops.tuner_ops.set_params)
        fe->ops.tuner_ops.set_params(fe);
    else
        err("it seems I don't have a tuner...");

    /* Enable automatic acquisition and reset cycle */
    cx24123_writereg(state, 0x03, (cx24123_readreg(state, 0x03) | 0x07));
    cx24123_writereg(state, 0x00, 0x10);
    cx24123_writereg(state, 0x00, 0);

    if (state->config->agc_callback)
        state->config->agc_callback(fe);

    return 0;
}

static int cx24123_get_frontend(struct dvb_frontend *fe)
{
    struct dtv_frontend_properties *p = &fe->dtv_property_cache;
    struct cx24123_state *state = fe->demodulator_priv;

    dprintk("\n");

    if (cx24123_get_inversion(state, &p->inversion) != 0) {
        err("%s: Failed to get inversion status\n", __func__);
        return -EREMOTEIO;
    }
    if (cx24123_get_fec(state, &p->fec_inner) != 0) {
        err("%s: Failed to get fec status\n", __func__);
        return -EREMOTEIO;
    }
    p->frequency = state->currentfreq;
    p->symbol_rate = state->currentsymbolrate;

    return 0;
}

static int cx24123_set_tone(struct dvb_frontend *fe, fe_sec_tone_mode_t tone)
{
    struct cx24123_state *state = fe->demodulator_priv;
    u8 val;

    /* wait for diseqc queue ready */
    cx24123_wait_for_diseqc(state);

    val = cx24123_readreg(state, 0x29) & ~0x40;

    switch (tone) {
    case SEC_TONE_ON:
        dprintk("setting tone on\n");
        return cx24123_writereg(state, 0x29, val | 0x10);
    case SEC_TONE_OFF:
        dprintk("setting tone off\n");
        return cx24123_writereg(state, 0x29, val & 0xef);
    default:
        err("CASE reached default with tone=%d\n", tone);
        return -EINVAL;
    }

    return 0;
}

static int cx24123_tune(struct dvb_frontend *fe,
            bool re_tune,
            unsigned int mode_flags,
            unsigned int *delay,
            fe_status_t *status)
{
    int retval = 0;

    if (re_tune)
        retval = cx24123_set_frontend(fe);

    if (!(mode_flags & FE_TUNE_MODE_ONESHOT))
        cx24123_read_status(fe, status);
    *delay = HZ/10;

    return retval;
}

static int cx24123_get_algo(struct dvb_frontend *fe)
{
    return 1; /* FE_ALGO_HW */
}

static void cx24123_release(struct dvb_frontend *fe)
{
    struct cx24123_state *state = fe->demodulator_priv;
    dprintk("\n");
    i2c_del_adapter(&state->tuner_i2c_adapter);
    kfree(state);
}

static int cx24123_tuner_i2c_tuner_xfer(struct i2c_adapter *i2c_adap,
    struct i2c_msg msg[], int num)
{
    struct cx24123_state *state = i2c_get_adapdata(i2c_adap);
    /* this repeater closes after the first stop */
    cx24123_repeater_mode(state, 1, 1);
    return i2c_transfer(state->i2c, msg, num);
}

static u32 cx24123_tuner_i2c_func(struct i2c_adapter *adapter)
{
    return I2C_FUNC_I2C;
}

static struct i2c_algorithm cx24123_tuner_i2c_algo = {
    .master_xfer   = cx24123_tuner_i2c_tuner_xfer,
    .functionality = cx24123_tuner_i2c_func,
};

struct i2c_adapter *
    cx24123_get_tuner_i2c_adapter(struct dvb_frontend *fe)
{
    struct cx24123_state *state = fe->demodulator_priv;
    return &state->tuner_i2c_adapter;
}
EXPORT_SYMBOL(cx24123_get_tuner_i2c_adapter);

static struct dvb_frontend_ops cx24123_ops;

struct dvb_frontend *cx24123_attach(const struct cx24123_config *config,
                    struct i2c_adapter *i2c)
{
    /* allocate memory for the internal state */
    struct cx24123_state *state =
        kzalloc(sizeof(struct cx24123_state), GFP_KERNEL);

    dprintk("\n");
    if (state == NULL) {
        err("Unable to kzalloc\n");
        goto error;
    }

    /* setup the state */
    state->config = config;
    state->i2c = i2c;

    /* check if the demod is there */
    state->demod_rev = cx24123_readreg(state, 0x00);
    switch (state->demod_rev) {
    case 0xe1:
        info("detected CX24123C\n");
        break;
    case 0xd1:
        info("detected CX24123\n");
        break;
    default:
        err("wrong demod revision: %x\n", state->demod_rev);
        goto error;
    }

    /* create dvb_frontend */
    memcpy(&state->frontend.ops, &cx24123_ops,
        sizeof(struct dvb_frontend_ops));
    state->frontend.demodulator_priv = state;

    /* create tuner i2c adapter */
    if (config->dont_use_pll)
        cx24123_repeater_mode(state, 1, 0);

    strlcpy(state->tuner_i2c_adapter.name, "CX24123 tuner I2C bus",
        sizeof(state->tuner_i2c_adapter.name));
    state->tuner_i2c_adapter.algo      = &cx24123_tuner_i2c_algo;
    state->tuner_i2c_adapter.algo_data = NULL;
    i2c_set_adapdata(&state->tuner_i2c_adapter, state);
    if (i2c_add_adapter(&state->tuner_i2c_adapter) < 0) {
        err("tuner i2c bus could not be initialized\n");
        goto error;
    }

    return &state->frontend;

error:
    kfree(state);

    return NULL;
}
EXPORT_SYMBOL(cx24123_attach);

static struct dvb_frontend_ops cx24123_ops = {
    .delsys = { SYS_DVBS },
    .info = {
        .name = "Conexant CX24123/CX24109",
        .frequency_min = 950000,
        .frequency_max = 2150000,
        .frequency_stepsize = 1011, /* kHz for QPSK frontends */
        .frequency_tolerance = 5000,
        .symbol_rate_min = 1000000,
        .symbol_rate_max = 45000000,
        .caps = FE_CAN_INVERSION_AUTO |
            FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
            FE_CAN_FEC_4_5 | FE_CAN_FEC_5_6 | FE_CAN_FEC_6_7 |
            FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
            FE_CAN_QPSK | FE_CAN_RECOVER
    },

    .release = cx24123_release,

    .init = cx24123_initfe,
    .set_frontend = cx24123_set_frontend,
    .get_frontend = cx24123_get_frontend,
    .read_status = cx24123_read_status,
    .read_ber = cx24123_read_ber,
    .read_signal_strength = cx24123_read_signal_strength,
    .read_snr = cx24123_read_snr,
    .diseqc_send_master_cmd = cx24123_send_diseqc_msg,
    .diseqc_send_burst = cx24123_diseqc_send_burst,
    .set_tone = cx24123_set_tone,
    .set_voltage = cx24123_set_voltage,
    .tune = cx24123_tune,
    .get_frontend_algo = cx24123_get_algo,
};

MODULE_DESCRIPTION("DVB Frontend module for Conexant " \
    "CX24123/CX24109/CX24113 hardware");
MODULE_AUTHOR("Steven Toth");
MODULE_LICENSE("GPL");