rtl2830.c

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/*
 * Realtek RTL2830 DVB-T demodulator driver
 *
 * Copyright (C) 2011 Antti Palosaari <[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.,
 *    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */


/*
 * Driver implements own I2C-adapter for tuner I2C access. That's since chip
 * have unusual I2C-gate control which closes gate automatically after each
 * I2C transfer. Using own I2C adapter we can workaround that.
 */

#include "rtl2830_priv.h"

/* write multiple hardware registers */
static int rtl2830_wr(struct rtl2830_priv *priv, u8 reg, const u8 *val, int len)
{
    int ret;
    u8 buf[1+len];
    struct i2c_msg msg[1] = {
        {
            .addr = priv->cfg.i2c_addr,
            .flags = 0,
            .len = 1+len,
            .buf = buf,
        }
    };

    buf[0] = reg;
    memcpy(&buf[1], val, len);

    ret = i2c_transfer(priv->i2c, msg, 1);
    if (ret == 1) {
        ret = 0;
    } else {
        dev_warn(&priv->i2c->dev, "%s: i2c wr failed=%d reg=%02x " \
                "len=%d\n", KBUILD_MODNAME, ret, reg, len);
        ret = -EREMOTEIO;
    }
    return ret;
}

/* read multiple hardware registers */
static int rtl2830_rd(struct rtl2830_priv *priv, u8 reg, u8 *val, int len)
{
    int ret;
    struct i2c_msg msg[2] = {
        {
            .addr = priv->cfg.i2c_addr,
            .flags = 0,
            .len = 1,
            .buf = &reg,
        }, {
            .addr = priv->cfg.i2c_addr,
            .flags = I2C_M_RD,
            .len = len,
            .buf = val,
        }
    };

    ret = i2c_transfer(priv->i2c, msg, 2);
    if (ret == 2) {
        ret = 0;
    } else {
        dev_warn(&priv->i2c->dev, "%s: i2c rd failed=%d reg=%02x " \
                "len=%d\n", KBUILD_MODNAME, ret, reg, len);
        ret = -EREMOTEIO;
    }
    return ret;
}

/* write multiple registers */
static int rtl2830_wr_regs(struct rtl2830_priv *priv, u16 reg, const u8 *val,
        int len)
{
    int ret;
    u8 reg2 = (reg >> 0) & 0xff;
    u8 page = (reg >> 8) & 0xff;

    /* switch bank if needed */
    if (page != priv->page) {
        ret = rtl2830_wr(priv, 0x00, &page, 1);
        if (ret)
            return ret;

        priv->page = page;
    }

    return rtl2830_wr(priv, reg2, val, len);
}

/* read multiple registers */
static int rtl2830_rd_regs(struct rtl2830_priv *priv, u16 reg, u8 *val, int len)
{
    int ret;
    u8 reg2 = (reg >> 0) & 0xff;
    u8 page = (reg >> 8) & 0xff;

    /* switch bank if needed */
    if (page != priv->page) {
        ret = rtl2830_wr(priv, 0x00, &page, 1);
        if (ret)
            return ret;

        priv->page = page;
    }

    return rtl2830_rd(priv, reg2, val, len);
}

/* read single register */
static int rtl2830_rd_reg(struct rtl2830_priv *priv, u16 reg, u8 *val)
{
    return rtl2830_rd_regs(priv, reg, val, 1);
}

/* write single register with mask */
int rtl2830_wr_reg_mask(struct rtl2830_priv *priv, u16 reg, u8 val, u8 mask)
{
    int ret;
    u8 tmp;

    /* no need for read if whole reg is written */
    if (mask != 0xff) {
        ret = rtl2830_rd_regs(priv, reg, &tmp, 1);
        if (ret)
            return ret;

        val &= mask;
        tmp &= ~mask;
        val |= tmp;
    }

    return rtl2830_wr_regs(priv, reg, &val, 1);
}

/* read single register with mask */
int rtl2830_rd_reg_mask(struct rtl2830_priv *priv, u16 reg, u8 *val, u8 mask)
{
    int ret, i;
    u8 tmp;

    ret = rtl2830_rd_regs(priv, reg, &tmp, 1);
    if (ret)
        return ret;

    tmp &= mask;

    /* find position of the first bit */
    for (i = 0; i < 8; i++) {
        if ((mask >> i) & 0x01)
            break;
    }
    *val = tmp >> i;

    return 0;
}

static int rtl2830_init(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    int ret, i;
    struct rtl2830_reg_val_mask tab[] = {
        { 0x00d, 0x01, 0x03 },
        { 0x00d, 0x10, 0x10 },
        { 0x104, 0x00, 0x1e },
        { 0x105, 0x80, 0x80 },
        { 0x110, 0x02, 0x03 },
        { 0x110, 0x08, 0x0c },
        { 0x17b, 0x00, 0x40 },
        { 0x17d, 0x05, 0x0f },
        { 0x17d, 0x50, 0xf0 },
        { 0x18c, 0x08, 0x0f },
        { 0x18d, 0x00, 0xc0 },
        { 0x188, 0x05, 0x0f },
        { 0x189, 0x00, 0xfc },
        { 0x2d5, 0x02, 0x02 },
        { 0x2f1, 0x02, 0x06 },
        { 0x2f1, 0x20, 0xf8 },
        { 0x16d, 0x00, 0x01 },
        { 0x1a6, 0x00, 0x80 },
        { 0x106, priv->cfg.vtop, 0x3f },
        { 0x107, priv->cfg.krf, 0x3f },
        { 0x112, 0x28, 0xff },
        { 0x103, priv->cfg.agc_targ_val, 0xff },
        { 0x00a, 0x02, 0x07 },
        { 0x140, 0x0c, 0x3c },
        { 0x140, 0x40, 0xc0 },
        { 0x15b, 0x05, 0x07 },
        { 0x15b, 0x28, 0x38 },
        { 0x15c, 0x05, 0x07 },
        { 0x15c, 0x28, 0x38 },
        { 0x115, priv->cfg.spec_inv, 0x01 },
        { 0x16f, 0x01, 0x07 },
        { 0x170, 0x18, 0x38 },
        { 0x172, 0x0f, 0x0f },
        { 0x173, 0x08, 0x38 },
        { 0x175, 0x01, 0x07 },
        { 0x176, 0x00, 0xc0 },
    };

    for (i = 0; i < ARRAY_SIZE(tab); i++) {
        ret = rtl2830_wr_reg_mask(priv, tab[i].reg, tab[i].val,
            tab[i].mask);
        if (ret)
            goto err;
    }

    ret = rtl2830_wr_regs(priv, 0x18f, "\x28\x00", 2);
    if (ret)
        goto err;

    ret = rtl2830_wr_regs(priv, 0x195,
        "\x04\x06\x0a\x12\x0a\x12\x1e\x28", 8);
    if (ret)
        goto err;

    /* TODO: spec init */

    /* soft reset */
    ret = rtl2830_wr_reg_mask(priv, 0x101, 0x04, 0x04);
    if (ret)
        goto err;

    ret = rtl2830_wr_reg_mask(priv, 0x101, 0x00, 0x04);
    if (ret)
        goto err;

    priv->sleeping = false;

    return ret;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_sleep(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    priv->sleeping = true;
    return 0;
}

int rtl2830_get_tune_settings(struct dvb_frontend *fe,
    struct dvb_frontend_tune_settings *s)
{
    s->min_delay_ms = 500;
    s->step_size = fe->ops.info.frequency_stepsize * 2;
    s->max_drift = (fe->ops.info.frequency_stepsize * 2) + 1;

    return 0;
}

static int rtl2830_set_frontend(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    struct dtv_frontend_properties *c = &fe->dtv_property_cache;
    int ret, i;
    u64 num;
    u8 buf[3], tmp;
    u32 if_ctl, if_frequency;
    static const u8 bw_params1[3][34] = {
        {
        0x1f, 0xf0, 0x1f, 0xf0, 0x1f, 0xfa, 0x00, 0x17, 0x00, 0x41,
        0x00, 0x64, 0x00, 0x67, 0x00, 0x38, 0x1f, 0xde, 0x1f, 0x7a,
        0x1f, 0x47, 0x1f, 0x7c, 0x00, 0x30, 0x01, 0x4b, 0x02, 0x82,
        0x03, 0x73, 0x03, 0xcf, /* 6 MHz */
        }, {
        0x1f, 0xfa, 0x1f, 0xda, 0x1f, 0xc1, 0x1f, 0xb3, 0x1f, 0xca,
        0x00, 0x07, 0x00, 0x4d, 0x00, 0x6d, 0x00, 0x40, 0x1f, 0xca,
        0x1f, 0x4d, 0x1f, 0x2a, 0x1f, 0xb2, 0x00, 0xec, 0x02, 0x7e,
        0x03, 0xd0, 0x04, 0x53, /* 7 MHz */
        }, {
        0x00, 0x10, 0x00, 0x0e, 0x1f, 0xf7, 0x1f, 0xc9, 0x1f, 0xa0,
        0x1f, 0xa6, 0x1f, 0xec, 0x00, 0x4e, 0x00, 0x7d, 0x00, 0x3a,
        0x1f, 0x98, 0x1f, 0x10, 0x1f, 0x40, 0x00, 0x75, 0x02, 0x5f,
        0x04, 0x24, 0x04, 0xdb, /* 8 MHz */
        },
    };
    static const u8 bw_params2[3][6] = {
        {0xc3, 0x0c, 0x44, 0x33, 0x33, 0x30}, /* 6 MHz */
        {0xb8, 0xe3, 0x93, 0x99, 0x99, 0x98}, /* 7 MHz */
        {0xae, 0xba, 0xf3, 0x26, 0x66, 0x64}, /* 8 MHz */
    };

    dev_dbg(&priv->i2c->dev,
            "%s: frequency=%d bandwidth_hz=%d inversion=%d\n",
            __func__, c->frequency, c->bandwidth_hz, c->inversion);

    /* program tuner */
    if (fe->ops.tuner_ops.set_params)
        fe->ops.tuner_ops.set_params(fe);

    switch (c->bandwidth_hz) {
    case 6000000:
        i = 0;
        break;
    case 7000000:
        i = 1;
        break;
    case 8000000:
        i = 2;
        break;
    default:
        dev_dbg(&priv->i2c->dev, "%s: invalid bandwidth\n", __func__);
        return -EINVAL;
    }

    ret = rtl2830_wr_reg_mask(priv, 0x008, i << 1, 0x06);
    if (ret)
        goto err;

    /* program if frequency */
    if (fe->ops.tuner_ops.get_if_frequency)
        ret = fe->ops.tuner_ops.get_if_frequency(fe, &if_frequency);
    else
        ret = -EINVAL;

    if (ret < 0)
        goto err;

    num = if_frequency % priv->cfg.xtal;
    num *= 0x400000;
    num = div_u64(num, priv->cfg.xtal);
    num = -num;
    if_ctl = num & 0x3fffff;
    dev_dbg(&priv->i2c->dev, "%s: if_frequency=%d if_ctl=%08x\n",
            __func__, if_frequency, if_ctl);

    ret = rtl2830_rd_reg_mask(priv, 0x119, &tmp, 0xc0); /* b[7:6] */
    if (ret)
        goto err;

    buf[0] = tmp << 6;
    buf[0] |= (if_ctl >> 16) & 0x3f;
    buf[1] = (if_ctl >>  8) & 0xff;
    buf[2] = (if_ctl >>  0) & 0xff;

    ret = rtl2830_wr_regs(priv, 0x119, buf, 3);
    if (ret)
        goto err;

    /* 1/2 split I2C write */
    ret = rtl2830_wr_regs(priv, 0x11c, &bw_params1[i][0], 17);
    if (ret)
        goto err;

    /* 2/2 split I2C write */
    ret = rtl2830_wr_regs(priv, 0x12d, &bw_params1[i][17], 17);
    if (ret)
        goto err;

    ret = rtl2830_wr_regs(priv, 0x19d, bw_params2[i], 6);
    if (ret)
        goto err;

    return ret;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_get_frontend(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    struct dtv_frontend_properties *c = &fe->dtv_property_cache;
    int ret;
    u8 buf[3];

    if (priv->sleeping)
        return 0;

    ret = rtl2830_rd_regs(priv, 0x33c, buf, 2);
    if (ret)
        goto err;

    ret = rtl2830_rd_reg(priv, 0x351, &buf[2]);
    if (ret)
        goto err;

    dev_dbg(&priv->i2c->dev, "%s: TPS=%*ph\n", __func__, 3, buf);

    switch ((buf[0] >> 2) & 3) {
    case 0:
        c->modulation = QPSK;
        break;
    case 1:
        c->modulation = QAM_16;
        break;
    case 2:
        c->modulation = QAM_64;
        break;
    }

    switch ((buf[2] >> 2) & 1) {
    case 0:
        c->transmission_mode = TRANSMISSION_MODE_2K;
        break;
    case 1:
        c->transmission_mode = TRANSMISSION_MODE_8K;
    }

    switch ((buf[2] >> 0) & 3) {
    case 0:
        c->guard_interval = GUARD_INTERVAL_1_32;
        break;
    case 1:
        c->guard_interval = GUARD_INTERVAL_1_16;
        break;
    case 2:
        c->guard_interval = GUARD_INTERVAL_1_8;
        break;
    case 3:
        c->guard_interval = GUARD_INTERVAL_1_4;
        break;
    }

    switch ((buf[0] >> 4) & 7) {
    case 0:
        c->hierarchy = HIERARCHY_NONE;
        break;
    case 1:
        c->hierarchy = HIERARCHY_1;
        break;
    case 2:
        c->hierarchy = HIERARCHY_2;
        break;
    case 3:
        c->hierarchy = HIERARCHY_4;
        break;
    }

    switch ((buf[1] >> 3) & 7) {
    case 0:
        c->code_rate_HP = FEC_1_2;
        break;
    case 1:
        c->code_rate_HP = FEC_2_3;
        break;
    case 2:
        c->code_rate_HP = FEC_3_4;
        break;
    case 3:
        c->code_rate_HP = FEC_5_6;
        break;
    case 4:
        c->code_rate_HP = FEC_7_8;
        break;
    }

    switch ((buf[1] >> 0) & 7) {
    case 0:
        c->code_rate_LP = FEC_1_2;
        break;
    case 1:
        c->code_rate_LP = FEC_2_3;
        break;
    case 2:
        c->code_rate_LP = FEC_3_4;
        break;
    case 3:
        c->code_rate_LP = FEC_5_6;
        break;
    case 4:
        c->code_rate_LP = FEC_7_8;
        break;
    }

    return 0;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_read_status(struct dvb_frontend *fe, fe_status_t *status)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    int ret;
    u8 tmp;
    *status = 0;

    if (priv->sleeping)
        return 0;

    ret = rtl2830_rd_reg_mask(priv, 0x351, &tmp, 0x78); /* [6:3] */
    if (ret)
        goto err;

    if (tmp == 11) {
        *status |= FE_HAS_SIGNAL | FE_HAS_CARRIER |
            FE_HAS_VITERBI | FE_HAS_SYNC | FE_HAS_LOCK;
    } else if (tmp == 10) {
        *status |= FE_HAS_SIGNAL | FE_HAS_CARRIER |
            FE_HAS_VITERBI;
    }

    return ret;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_read_snr(struct dvb_frontend *fe, u16 *snr)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    int ret, hierarchy, constellation;
    u8 buf[2], tmp;
    u16 tmp16;
#define CONSTELLATION_NUM 3
#define HIERARCHY_NUM 4
    static const u32 snr_constant[CONSTELLATION_NUM][HIERARCHY_NUM] = {
        { 70705899, 70705899, 70705899, 70705899 },
        { 82433173, 82433173, 87483115, 94445660 },
        { 92888734, 92888734, 95487525, 99770748 },
    };

    if (priv->sleeping)
        return 0;

    /* reports SNR in resolution of 0.1 dB */

    ret = rtl2830_rd_reg(priv, 0x33c, &tmp);
    if (ret)
        goto err;

    constellation = (tmp >> 2) & 0x03; /* [3:2] */
    if (constellation > CONSTELLATION_NUM - 1)
        goto err;

    hierarchy = (tmp >> 4) & 0x07; /* [6:4] */
    if (hierarchy > HIERARCHY_NUM - 1)
        goto err;

    ret = rtl2830_rd_regs(priv, 0x40c, buf, 2);
    if (ret)
        goto err;

    tmp16 = buf[0] << 8 | buf[1];

    if (tmp16)
        *snr = (snr_constant[constellation][hierarchy] -
                intlog10(tmp16)) / ((1 << 24) / 100);
    else
        *snr = 0;

    return 0;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_read_ber(struct dvb_frontend *fe, u32 *ber)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    int ret;
    u8 buf[2];

    if (priv->sleeping)
        return 0;

    ret = rtl2830_rd_regs(priv, 0x34e, buf, 2);
    if (ret)
        goto err;

    *ber = buf[0] << 8 | buf[1];

    return 0;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static int rtl2830_read_ucblocks(struct dvb_frontend *fe, u32 *ucblocks)
{
    *ucblocks = 0;
    return 0;
}

static int rtl2830_read_signal_strength(struct dvb_frontend *fe, u16 *strength)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    int ret;
    u8 buf[2];
    u16 if_agc_raw, if_agc;

    if (priv->sleeping)
        return 0;

    ret = rtl2830_rd_regs(priv, 0x359, buf, 2);
    if (ret)
        goto err;

    if_agc_raw = (buf[0] << 8 | buf[1]) & 0x3fff;

    if (if_agc_raw & (1 << 9))
        if_agc = -(~(if_agc_raw - 1) & 0x1ff);
    else
        if_agc = if_agc_raw;

    *strength = (u8) (55 - if_agc / 182);
    *strength |= *strength << 8;

    return 0;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static struct dvb_frontend_ops rtl2830_ops;

static u32 rtl2830_tuner_i2c_func(struct i2c_adapter *adapter)
{
    return I2C_FUNC_I2C;
}

static int rtl2830_tuner_i2c_xfer(struct i2c_adapter *i2c_adap,
    struct i2c_msg msg[], int num)
{
    struct rtl2830_priv *priv = i2c_get_adapdata(i2c_adap);
    int ret;

    /* open i2c-gate */
    ret = rtl2830_wr_reg_mask(priv, 0x101, 0x08, 0x08);
    if (ret)
        goto err;

    ret = i2c_transfer(priv->i2c, msg, num);
    if (ret < 0)
        dev_warn(&priv->i2c->dev, "%s: tuner i2c failed=%d\n",
            KBUILD_MODNAME, ret);

    return ret;
err:
    dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
    return ret;
}

static struct i2c_algorithm rtl2830_tuner_i2c_algo = {
    .master_xfer   = rtl2830_tuner_i2c_xfer,
    .functionality = rtl2830_tuner_i2c_func,
};

struct i2c_adapter *rtl2830_get_tuner_i2c_adapter(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;
    return &priv->tuner_i2c_adapter;
}
EXPORT_SYMBOL(rtl2830_get_tuner_i2c_adapter);

static void rtl2830_release(struct dvb_frontend *fe)
{
    struct rtl2830_priv *priv = fe->demodulator_priv;

    i2c_del_adapter(&priv->tuner_i2c_adapter);
    kfree(priv);
}

struct dvb_frontend *rtl2830_attach(const struct rtl2830_config *cfg,
    struct i2c_adapter *i2c)
{
    struct rtl2830_priv *priv = NULL;
    int ret = 0;
    u8 tmp;

    /* allocate memory for the internal state */
    priv = kzalloc(sizeof(struct rtl2830_priv), GFP_KERNEL);
    if (priv == NULL)
        goto err;

    /* setup the priv */
    priv->i2c = i2c;
    memcpy(&priv->cfg, cfg, sizeof(struct rtl2830_config));

    /* check if the demod is there */
    ret = rtl2830_rd_reg(priv, 0x000, &tmp);
    if (ret)
        goto err;

    /* create dvb_frontend */
    memcpy(&priv->fe.ops, &rtl2830_ops, sizeof(struct dvb_frontend_ops));
    priv->fe.demodulator_priv = priv;

    /* create tuner i2c adapter */
    strlcpy(priv->tuner_i2c_adapter.name, "RTL2830 tuner I2C adapter",
        sizeof(priv->tuner_i2c_adapter.name));
    priv->tuner_i2c_adapter.algo = &rtl2830_tuner_i2c_algo;
    priv->tuner_i2c_adapter.algo_data = NULL;
    i2c_set_adapdata(&priv->tuner_i2c_adapter, priv);
    if (i2c_add_adapter(&priv->tuner_i2c_adapter) < 0) {
        dev_err(&i2c->dev,
                "%s: tuner i2c bus could not be initialized\n",
                KBUILD_MODNAME);
        goto err;
    }

    priv->sleeping = true;

    return &priv->fe;
err:
    dev_dbg(&i2c->dev, "%s: failed=%d\n", __func__, ret);
    kfree(priv);
    return NULL;
}
EXPORT_SYMBOL(rtl2830_attach);

static struct dvb_frontend_ops rtl2830_ops = {
    .delsys = { SYS_DVBT },
    .info = {
        .name = "Realtek RTL2830 (DVB-T)",
        .caps = FE_CAN_FEC_1_2 |
            FE_CAN_FEC_2_3 |
            FE_CAN_FEC_3_4 |
            FE_CAN_FEC_5_6 |
            FE_CAN_FEC_7_8 |
            FE_CAN_FEC_AUTO |
            FE_CAN_QPSK |
            FE_CAN_QAM_16 |
            FE_CAN_QAM_64 |
            FE_CAN_QAM_AUTO |
            FE_CAN_TRANSMISSION_MODE_AUTO |
            FE_CAN_GUARD_INTERVAL_AUTO |
            FE_CAN_HIERARCHY_AUTO |
            FE_CAN_RECOVER |
            FE_CAN_MUTE_TS
    },

    .release = rtl2830_release,

    .init = rtl2830_init,
    .sleep = rtl2830_sleep,

    .get_tune_settings = rtl2830_get_tune_settings,

    .set_frontend = rtl2830_set_frontend,
    .get_frontend = rtl2830_get_frontend,

    .read_status = rtl2830_read_status,
    .read_snr = rtl2830_read_snr,
    .read_ber = rtl2830_read_ber,
    .read_ucblocks = rtl2830_read_ucblocks,
    .read_signal_strength = rtl2830_read_signal_strength,
};

MODULE_AUTHOR("Antti Palosaari <[email protected]>");
MODULE_DESCRIPTION("Realtek RTL2830 DVB-T demodulator driver");
MODULE_LICENSE("GPL");