// SPDX-License-Identifier: GPL-2.0
// Rafael Micro R820T driver
//
// Copyright (C) 2013 Mauro Carvalho Chehab
//
// This driver was written from scratch, based on an existing driver
// that it is part of rtl-sdr git tree, released under GPLv2:
//      https://groups.google.com/forum/#!topic/ultra-cheap-sdr/Y3rBEOFtHug
//      https://github.com/n1gp/gr-baz
//
// From what I understood from the threads, the original driver was converted
// to userspace from a Realtek tree. I couldn't find the original tree.
// However, the original driver look awkward on my eyes. So, I decided to
// write a new version from it from the scratch, while trying to reproduce
// everything found there.
//
// TODO:
//      After locking, the original driver seems to have some routines to
//              improve reception. This was not implemented here yet.
//
//      RF Gain set/get is not implemented.

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/videodev2.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/bitrev.h>

#include "tuner-i2c.h"
#include "r820t.h"

/*
 * FIXME: I think that there are only 32 registers, but better safe than
 *        sorry. After finishing the driver, we may review it.
 */
#define REG_SHADOW_START        5
#define NUM_REGS                27
#define NUM_IMR                 5
#define IMR_TRIAL               9

#define VER_NUM  49

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "enable verbose debug messages");

static int no_imr_cal;
module_param(no_imr_cal, int, 0444);
MODULE_PARM_DESC(no_imr_cal, "Disable IMR calibration at module init");


/*
 * enums and structures
 */

enum xtal_cap_value {
        XTAL_LOW_CAP_30P = 0,
        XTAL_LOW_CAP_20P,
        XTAL_LOW_CAP_10P,
        XTAL_LOW_CAP_0P,
        XTAL_HIGH_CAP_0P
};

struct r820t_sect_type {
        u8      phase_y;
        u8      gain_x;
        u16     value;
};

struct r820t_priv {
        struct list_head                hybrid_tuner_instance_list;
        const struct r820t_config       *cfg;
        struct tuner_i2c_props          i2c_props;
        struct mutex                    lock;

        u8                              regs[NUM_REGS];
        u8                              buf[NUM_REGS + 1];
        enum xtal_cap_value             xtal_cap_sel;
        u16                             pll;    /* kHz */
        u32                             int_freq;
        u8                              fil_cal_code;
        bool                            imr_done;
        bool                            has_lock;
        bool                            init_done;
        struct r820t_sect_type          imr_data[NUM_IMR];

        /* Store current mode */
        u32                             delsys;
        enum v4l2_tuner_type            type;
        v4l2_std_id                     std;
        u32                             bw;     /* in MHz */
};

struct r820t_freq_range {
        u32     freq;
        u8      open_d;
        u8      rf_mux_ploy;
        u8      tf_c;
        u8      xtal_cap20p;
        u8      xtal_cap10p;
        u8      xtal_cap0p;
        u8      imr_mem;                /* Not used, currently */
};

#define VCO_POWER_REF   0x02
#define DIP_FREQ        32000000

/*
 * Static constants
 */

static LIST_HEAD(hybrid_tuner_instance_list);
static DEFINE_MUTEX(r820t_list_mutex);

/* Those initial values start from REG_SHADOW_START */
static const u8 r820t_init_array[NUM_REGS] = {
        0x83, 0x32, 0x75,                       /* 05 to 07 */
        0xc0, 0x40, 0xd6, 0x6c,                 /* 08 to 0b */
        0xf5, 0x63, 0x75, 0x68,                 /* 0c to 0f */
        0x6c, 0x83, 0x80, 0x00,                 /* 10 to 13 */
        0x0f, 0x00, 0xc0, 0x30,                 /* 14 to 17 */
        0x48, 0xcc, 0x60, 0x00,                 /* 18 to 1b */
        0x54, 0xae, 0x4a, 0xc0                  /* 1c to 1f */
};

/* Tuner frequency ranges */
static const struct r820t_freq_range freq_ranges[] = {
        {
                .freq = 0,
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0xdf,           /* R27[7:0]  band2,band0 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 50,             /* Start freq, in MHz */
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0xbe,           /* R27[7:0]  band4,band1  */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 55,             /* Start freq, in MHz */
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x8b,           /* R27[7:0]  band7,band4 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 60,             /* Start freq, in MHz */
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x7b,           /* R27[7:0]  band8,band4 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 65,             /* Start freq, in MHz */
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x69,           /* R27[7:0]  band9,band6 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 70,             /* Start freq, in MHz */
                .open_d = 0x08,         /* low */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x58,           /* R27[7:0]  band10,band7 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 75,             /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x44,           /* R27[7:0]  band11,band11 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 80,             /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x44,           /* R27[7:0]  band11,band11 */
                .xtal_cap20p = 0x02,    /* R16[1:0]  20pF (10)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 90,             /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x34,           /* R27[7:0]  band12,band11 */
                .xtal_cap20p = 0x01,    /* R16[1:0]  10pF (01)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 100,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x34,           /* R27[7:0]  band12,band11 */
                .xtal_cap20p = 0x01,    /* R16[1:0]  10pF (01)    */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 0,
        }, {
                .freq = 110,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x24,           /* R27[7:0]  band13,band11 */
                .xtal_cap20p = 0x01,    /* R16[1:0]  10pF (01)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 1,
        }, {
                .freq = 120,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x24,           /* R27[7:0]  band13,band11 */
                .xtal_cap20p = 0x01,    /* R16[1:0]  10pF (01)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 1,
        }, {
                .freq = 140,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x14,           /* R27[7:0]  band14,band11 */
                .xtal_cap20p = 0x01,    /* R16[1:0]  10pF (01)   */
                .xtal_cap10p = 0x01,
                .xtal_cap0p = 0x00,
                .imr_mem = 1,
        }, {
                .freq = 180,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x13,           /* R27[7:0]  band14,band12 */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 1,
        }, {
                .freq = 220,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x13,           /* R27[7:0]  band14,band12 */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 2,
        }, {
                .freq = 250,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x11,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 2,
        }, {
                .freq = 280,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x02,    /* R26[7:6]=0 (LPF)  R26[1:0]=2 (low) */
                .tf_c = 0x00,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 2,
        }, {
                .freq = 310,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x41,    /* R26[7:6]=1 (bypass)  R26[1:0]=1 (middle) */
                .tf_c = 0x00,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 2,
        }, {
                .freq = 450,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x41,    /* R26[7:6]=1 (bypass)  R26[1:0]=1 (middle) */
                .tf_c = 0x00,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 3,
        }, {
                .freq = 588,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x40,    /* R26[7:6]=1 (bypass)  R26[1:0]=0 (highest) */
                .tf_c = 0x00,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 3,
        }, {
                .freq = 650,            /* Start freq, in MHz */
                .open_d = 0x00,         /* high */
                .rf_mux_ploy = 0x40,    /* R26[7:6]=1 (bypass)  R26[1:0]=0 (highest) */
                .tf_c = 0x00,           /* R27[7:0]  highest,highest */
                .xtal_cap20p = 0x00,    /* R16[1:0]  0pF (00)   */
                .xtal_cap10p = 0x00,
                .xtal_cap0p = 0x00,
                .imr_mem = 4,
        }
};

static int r820t_xtal_capacitor[][2] = {
        { 0x0b, XTAL_LOW_CAP_30P },
        { 0x02, XTAL_LOW_CAP_20P },
        { 0x01, XTAL_LOW_CAP_10P },
        { 0x00, XTAL_LOW_CAP_0P  },
        { 0x10, XTAL_HIGH_CAP_0P },
};

/*
 * I2C read/write code and shadow registers logic
 */
static void shadow_store(struct r820t_priv *priv, u8 reg, const u8 *val,
                         int len)
{
        int r = reg - REG_SHADOW_START;

        if (r < 0) {
                len += r;
                r = 0;
        }
        if (len <= 0)
                return;
        if (len > NUM_REGS - r)
                len = NUM_REGS - r;

        tuner_dbg("%s: prev  reg=%02x len=%d: %*ph\n",
                  __func__, r + REG_SHADOW_START, len, len, val);

        memcpy(&priv->regs[r], val, len);
}

static int r820t_write(struct r820t_priv *priv, u8 reg, const u8 *val,
                       int len)
{
        int rc, size, pos = 0;

        /* Store the shadow registers */
        shadow_store(priv, reg, val, len);

        do {
                if (len > priv->cfg->max_i2c_msg_len - 1)
                        size = priv->cfg->max_i2c_msg_len - 1;
                else
                        size = len;

                /* Fill I2C buffer */
                priv->buf[0] = reg;
                memcpy(&priv->buf[1], &val[pos], size);

                rc = tuner_i2c_xfer_send(&priv->i2c_props, priv->buf, size + 1);
                if (rc != size + 1) {
                        tuner_info("%s: i2c wr failed=%d reg=%02x len=%d: %*ph\n",
                                   __func__, rc, reg, size, size, &priv->buf[1]);
                        if (rc < 0)
                                return rc;
                        return -EREMOTEIO;
                }
                tuner_dbg("%s: i2c wr reg=%02x len=%d: %*ph\n",
                          __func__, reg, size, size, &priv->buf[1]);

                reg += size;
                len -= size;
                pos += size;
        } while (len > 0);

        return 0;
}

static inline int r820t_write_reg(struct r820t_priv *priv, u8 reg, u8 val)
{
        u8 tmp = val; /* work around GCC PR81715 with asan-stack=1 */

        return r820t_write(priv, reg, &tmp, 1);
}

static int r820t_read_cache_reg(struct r820t_priv *priv, int reg)
{
        reg -= REG_SHADOW_START;

        if (reg >= 0 && reg < NUM_REGS)
                return priv->regs[reg];
        else
                return -EINVAL;
}

static inline int r820t_write_reg_mask(struct r820t_priv *priv, u8 reg, u8 val,
                                u8 bit_mask)
{
        u8 tmp = val;
        int rc = r820t_read_cache_reg(priv, reg);

        if (rc < 0)
                return rc;

        tmp = (rc & ~bit_mask) | (tmp & bit_mask);

        return r820t_write(priv, reg, &tmp, 1);
}

static int r820t_read(struct r820t_priv *priv, u8 reg, u8 *val, int len)
{
        int rc, i;
        u8 *p = &priv->buf[1];

        priv->buf[0] = reg;

        rc = tuner_i2c_xfer_send_recv(&priv->i2c_props, priv->buf, 1, p, len);
        if (rc != len) {
                tuner_info("%s: i2c rd failed=%d reg=%02x len=%d: %*ph\n",
                           __func__, rc, reg, len, len, p);
                if (rc < 0)
                        return rc;
                return -EREMOTEIO;
        }

        /* Copy data to the output buffer */
        for (i = 0; i < len; i++)
                val[i] = bitrev8(p[i]);

        tuner_dbg("%s: i2c rd reg=%02x len=%d: %*ph\n",
                  __func__, reg, len, len, val);

        return 0;
}

/*
 * r820t tuning logic
 */

static int r820t_set_mux(struct r820t_priv *priv, u32 freq)
{
        const struct r820t_freq_range *range;
        int i, rc;
        u8 val, reg08, reg09;

        /* Get the proper frequency range */
        freq = freq / 1000000;
        for (i = 0; i < ARRAY_SIZE(freq_ranges) - 1; i++) {
                if (freq < freq_ranges[i + 1].freq)
                        break;
        }
        range = &freq_ranges[i];

        tuner_dbg("set r820t range#%d for frequency %d MHz\n", i, freq);

        /* Open Drain */
        rc = r820t_write_reg_mask(priv, 0x17, range->open_d, 0x08);
        if (rc < 0)
                return rc;

        /* RF_MUX,Polymux */
        rc = r820t_write_reg_mask(priv, 0x1a, range->rf_mux_ploy, 0xc3);
        if (rc < 0)
                return rc;

        /* TF BAND */
        rc = r820t_write_reg(priv, 0x1b, range->tf_c);
        if (rc < 0)
                return rc;

        /* XTAL CAP & Drive */
        switch (priv->xtal_cap_sel) {
        case XTAL_LOW_CAP_30P:
        case XTAL_LOW_CAP_20P:
                val = range->xtal_cap20p | 0x08;
                break;
        case XTAL_LOW_CAP_10P:
                val = range->xtal_cap10p | 0x08;
                break;
        case XTAL_HIGH_CAP_0P:
                val = range->xtal_cap0p | 0x00;
                break;
        default:
        case XTAL_LOW_CAP_0P:
                val = range->xtal_cap0p | 0x08;
                break;
        }
        rc = r820t_write_reg_mask(priv, 0x10, val, 0x0b);
        if (rc < 0)
                return rc;

        if (priv->imr_done) {
                reg08 = priv->imr_data[range->imr_mem].gain_x;
                reg09 = priv->imr_data[range->imr_mem].phase_y;
        } else {
                reg08 = 0;
                reg09 = 0;
        }
        rc = r820t_write_reg_mask(priv, 0x08, reg08, 0x3f);
        if (rc < 0)
                return rc;

        rc = r820t_write_reg_mask(priv, 0x09, reg09, 0x3f);

        return rc;
}

static int r820t_set_pll(struct r820t_priv *priv, enum v4l2_tuner_type type,
                         u32 freq)
{
        u32 vco_freq;
        int rc, i;
        unsigned sleep_time = 10000;
        u32 vco_fra;            /* VCO contribution by SDM (kHz) */
        u32 vco_min  = 1770000;
        u32 vco_max  = vco_min * 2;
        u32 pll_ref;
        u16 n_sdm = 2;
        u16 sdm = 0;
        u8 mix_div = 2;
        u8 div_buf = 0;
        u8 div_num = 0;
        u8 refdiv2 = 0;
        u8 ni, si, nint, vco_fine_tune, val;
        u8 data[5];

        /* Frequency in kHz */
        freq = freq / 1000;
        pll_ref = priv->cfg->xtal / 1000;

#if 0
        /* Doesn't exist on rtl-sdk, and on field tests, caused troubles */
        if ((priv->cfg->rafael_chip == CHIP_R620D) ||
           (priv->cfg->rafael_chip == CHIP_R828D) ||
           (priv->cfg->rafael_chip == CHIP_R828)) {
                /* ref set refdiv2, reffreq = Xtal/2 on ATV application */
                if (type != V4L2_TUNER_DIGITAL_TV) {
                        pll_ref /= 2;
                        refdiv2 = 0x10;
                        sleep_time = 20000;
                }
        } else {
                if (priv->cfg->xtal > 24000000) {
                        pll_ref /= 2;
                        refdiv2 = 0x10;
                }
        }
#endif

        rc = r820t_write_reg_mask(priv, 0x10, refdiv2, 0x10);
        if (rc < 0)
                return rc;

        /* set pll autotune = 128kHz */
        rc = r820t_write_reg_mask(priv, 0x1a, 0x00, 0x0c);
        if (rc < 0)
                return rc;

        /* set VCO current = 100 */
        rc = r820t_write_reg_mask(priv, 0x12, 0x80, 0xe0);
        if (rc < 0)
                return rc;

        /* Calculate divider */
        while (mix_div <= 64) {
                if (((freq * mix_div) >= vco_min) &&
                   ((freq * mix_div) < vco_max)) {
                        div_buf = mix_div;
                        while (div_buf > 2) {
                                div_buf = div_buf >> 1;
                                div_num++;
                        }
                        break;
                }
                mix_div = mix_div << 1;
        }

        rc = r820t_read(priv, 0x00, data, sizeof(data));
        if (rc < 0)
                return rc;

        vco_fine_tune = (data[4] & 0x30) >> 4;

        tuner_dbg("mix_div=%d div_num=%d vco_fine_tune=%d\n",
                        mix_div, div_num, vco_fine_tune);

        /*
         * XXX: R828D/16MHz seems to have always vco_fine_tune=1.
         * Due to that, this calculation goes wrong.
         */
        if (priv->cfg->rafael_chip != CHIP_R828D) {
                if (vco_fine_tune > VCO_POWER_REF)
                        div_num = div_num - 1;
                else if (vco_fine_tune < VCO_POWER_REF)
                        div_num = div_num + 1;
        }

        rc = r820t_write_reg_mask(priv, 0x10, div_num << 5, 0xe0);
        if (rc < 0)
                return rc;

        vco_freq = freq * mix_div;
        nint = vco_freq / (2 * pll_ref);
        vco_fra = vco_freq - 2 * pll_ref * nint;

        /* boundary spur prevention */
        if (vco_fra < pll_ref / 64) {
                vco_fra = 0;
        } else if (vco_fra > pll_ref * 127 / 64) {
                vco_fra = 0;
                nint++;
        } else if ((vco_fra > pll_ref * 127 / 128) && (vco_fra < pll_ref)) {
                vco_fra = pll_ref * 127 / 128;
        } else if ((vco_fra > pll_ref) && (vco_fra < pll_ref * 129 / 128)) {
                vco_fra = pll_ref * 129 / 128;
        }

        ni = (nint - 13) / 4;
        si = nint - 4 * ni - 13;

        rc = r820t_write_reg(priv, 0x14, ni + (si << 6));
        if (rc < 0)
                return rc;

        /* pw_sdm */
        if (!vco_fra)
                val = 0x08;
        else
                val = 0x00;

        rc = r820t_write_reg_mask(priv, 0x12, val, 0x08);
        if (rc < 0)
                return rc;

        /* sdm calculator */
        while (vco_fra > 1) {
                if (vco_fra > (2 * pll_ref / n_sdm)) {
                        sdm = sdm + 32768 / (n_sdm / 2);
                        vco_fra = vco_fra - 2 * pll_ref / n_sdm;
                        if (n_sdm >= 0x8000)
                                break;
                }
                n_sdm = n_sdm << 1;
        }

        tuner_dbg("freq %d kHz, pll ref %d%s, sdm=0x%04x\n",
                  freq, pll_ref, refdiv2 ? " / 2" : "", sdm);

        rc = r820t_write_reg(priv, 0x16, sdm >> 8);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x15, sdm & 0xff);
        if (rc < 0)
                return rc;

        for (i = 0; i < 2; i++) {
                usleep_range(sleep_time, sleep_time + 1000);

                /* Check if PLL has locked */
                rc = r820t_read(priv, 0x00, data, 3);
                if (rc < 0)
                        return rc;
                if (data[2] & 0x40)
                        break;

                if (!i) {
                        /* Didn't lock. Increase VCO current */
                        rc = r820t_write_reg_mask(priv, 0x12, 0x60, 0xe0);
                        if (rc < 0)
                                return rc;
                }
        }

        if (!(data[2] & 0x40)) {
                priv->has_lock = false;
                return 0;
        }

        priv->has_lock = true;
        tuner_dbg("tuner has lock at frequency %d kHz\n", freq);

        /* set pll autotune = 8kHz */
        rc = r820t_write_reg_mask(priv, 0x1a, 0x08, 0x08);

        return rc;
}

static int r820t_sysfreq_sel(struct r820t_priv *priv, u32 freq,
                             enum v4l2_tuner_type type,
                             v4l2_std_id std,
                             u32 delsys)
{
        int rc;
        u8 mixer_top, lna_top, cp_cur, div_buf_cur, lna_vth_l, mixer_vth_l;
        u8 air_cable1_in, cable2_in, pre_dect, lna_discharge, filter_cur;

        tuner_dbg("adjusting tuner parameters for the standard\n");

        switch (delsys) {
        case SYS_DVBT:
                if ((freq == 506000000) || (freq == 666000000) ||
                   (freq == 818000000)) {
                        mixer_top = 0x14;       /* mixer top:14 , top-1, low-discharge */
                        lna_top = 0xe5;         /* detect bw 3, lna top:4, predet top:2 */
                        cp_cur = 0x28;          /* 101, 0.2 */
                        div_buf_cur = 0x20;     /* 10, 200u */
                } else {
                        mixer_top = 0x24;       /* mixer top:13 , top-1, low-discharge */
                        lna_top = 0xe5;         /* detect bw 3, lna top:4, predet top:2 */
                        cp_cur = 0x38;          /* 111, auto */
                        div_buf_cur = 0x30;     /* 11, 150u */
                }
                lna_vth_l = 0x53;               /* lna vth 0.84 ,  vtl 0.64 */
                mixer_vth_l = 0x75;             /* mixer vth 1.04, vtl 0.84 */
                air_cable1_in = 0x00;
                cable2_in = 0x00;
                pre_dect = 0x40;
                lna_discharge = 14;
                filter_cur = 0x40;              /* 10, low */
                break;
        case SYS_DVBT2:
                mixer_top = 0x24;       /* mixer top:13 , top-1, low-discharge */
                lna_top = 0xe5;         /* detect bw 3, lna top:4, predet top:2 */
                lna_vth_l = 0x53;       /* lna vth 0.84 ,  vtl 0.64 */
                mixer_vth_l = 0x75;     /* mixer vth 1.04, vtl 0.84 */
                air_cable1_in = 0x00;
                cable2_in = 0x00;
                pre_dect = 0x40;
                lna_discharge = 14;
                cp_cur = 0x38;          /* 111, auto */
                div_buf_cur = 0x30;     /* 11, 150u */
                filter_cur = 0x40;      /* 10, low */
                break;
        case SYS_ISDBT:
                mixer_top = 0x24;       /* mixer top:13 , top-1, low-discharge */
                lna_top = 0xe5;         /* detect bw 3, lna top:4, predet top:2 */
                lna_vth_l = 0x75;       /* lna vth 1.04 ,  vtl 0.84 */
                mixer_vth_l = 0x75;     /* mixer vth 1.04, vtl 0.84 */
                air_cable1_in = 0x00;
                cable2_in = 0x00;
                pre_dect = 0x40;
                lna_discharge = 14;
                cp_cur = 0x38;          /* 111, auto */
                div_buf_cur = 0x30;     /* 11, 150u */
                filter_cur = 0x40;      /* 10, low */
                break;
        case SYS_DVBC_ANNEX_A:
                mixer_top = 0x24;       /* mixer top:13 , top-1, low-discharge */
                lna_top = 0xe5;
                lna_vth_l = 0x62;
                mixer_vth_l = 0x75;
                air_cable1_in = 0x60;
                cable2_in = 0x00;
                pre_dect = 0x40;
                lna_discharge = 14;
                cp_cur = 0x38;          /* 111, auto */
                div_buf_cur = 0x30;     /* 11, 150u */
                filter_cur = 0x40;      /* 10, low */
                break;
        default: /* DVB-T 8M */
                mixer_top = 0x24;       /* mixer top:13 , top-1, low-discharge */
                lna_top = 0xe5;         /* detect bw 3, lna top:4, predet top:2 */
                lna_vth_l = 0x53;       /* lna vth 0.84 ,  vtl 0.64 */
                mixer_vth_l = 0x75;     /* mixer vth 1.04, vtl 0.84 */
                air_cable1_in = 0x00;
                cable2_in = 0x00;
                pre_dect = 0x40;
                lna_discharge = 14;
                cp_cur = 0x38;          /* 111, auto */
                div_buf_cur = 0x30;     /* 11, 150u */
                filter_cur = 0x40;      /* 10, low */
                break;
        }

        if (priv->cfg->use_diplexer &&
           ((priv->cfg->rafael_chip == CHIP_R820T) ||
           (priv->cfg->rafael_chip == CHIP_R828S) ||
           (priv->cfg->rafael_chip == CHIP_R820C))) {
                if (freq > DIP_FREQ)
                        air_cable1_in = 0x00;
                else
                        air_cable1_in = 0x60;
                cable2_in = 0x00;
        }


        if (priv->cfg->use_predetect) {
                rc = r820t_write_reg_mask(priv, 0x06, pre_dect, 0x40);
                if (rc < 0)
                        return rc;
        }

        rc = r820t_write_reg_mask(priv, 0x1d, lna_top, 0xc7);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg_mask(priv, 0x1c, mixer_top, 0xf8);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x0d, lna_vth_l);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x0e, mixer_vth_l);
        if (rc < 0)
                return rc;

        /* Air-IN only for Astrometa */
        rc = r820t_write_reg_mask(priv, 0x05, air_cable1_in, 0x60);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg_mask(priv, 0x06, cable2_in, 0x08);
        if (rc < 0)
                return rc;

        rc = r820t_write_reg_mask(priv, 0x11, cp_cur, 0x38);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg_mask(priv, 0x17, div_buf_cur, 0x30);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg_mask(priv, 0x0a, filter_cur, 0x60);
        if (rc < 0)
                return rc;
        /*
         * Original driver initializes regs 0x05 and 0x06 with the
         * same value again on this point. Probably, it is just an
         * error there
         */

        /*
         * Set LNA
         */

        tuner_dbg("adjusting LNA parameters\n");
        if (type != V4L2_TUNER_ANALOG_TV) {
                /* LNA TOP: lowest */
                rc = r820t_write_reg_mask(priv, 0x1d, 0, 0x38);
                if (rc < 0)
                        return rc;

                /* 0: normal mode */
                rc = r820t_write_reg_mask(priv, 0x1c, 0, 0x04);
                if (rc < 0)
                        return rc;

                /* 0: PRE_DECT off */
                rc = r820t_write_reg_mask(priv, 0x06, 0, 0x40);
                if (rc < 0)
                        return rc;

                /* agc clk 250hz */
                rc = r820t_write_reg_mask(priv, 0x1a, 0x30, 0x30);
                if (rc < 0)
                        return rc;

                msleep(250);

                /* write LNA TOP = 3 */
                rc = r820t_write_reg_mask(priv, 0x1d, 0x18, 0x38);
                if (rc < 0)
                        return rc;

                /*
                 * write discharge mode
                 * FIXME: IMHO, the mask here is wrong, but it matches
                 * what's there at the original driver
                 */
                rc = r820t_write_reg_mask(priv, 0x1c, mixer_top, 0x04);
                if (rc < 0)
                        return rc;

                /* LNA discharge current */
                rc = r820t_write_reg_mask(priv, 0x1e, lna_discharge, 0x1f);
                if (rc < 0)
                        return rc;

                /* agc clk 60hz */
                rc = r820t_write_reg_mask(priv, 0x1a, 0x20, 0x30);
                if (rc < 0)
                        return rc;
        } else {
                /* PRE_DECT off */
                rc = r820t_write_reg_mask(priv, 0x06, 0, 0x40);
                if (rc < 0)
                        return rc;

                /* write LNA TOP */
                rc = r820t_write_reg_mask(priv, 0x1d, lna_top, 0x38);
                if (rc < 0)
                        return rc;

                /*
                 * write discharge mode
                 * FIXME: IMHO, the mask here is wrong, but it matches
                 * what's there at the original driver
                 */
                rc = r820t_write_reg_mask(priv, 0x1c, mixer_top, 0x04);
                if (rc < 0)
                        return rc;

                /* LNA discharge current */
                rc = r820t_write_reg_mask(priv, 0x1e, lna_discharge, 0x1f);
                if (rc < 0)
                        return rc;

                /* agc clk 1Khz, external det1 cap 1u */
                rc = r820t_write_reg_mask(priv, 0x1a, 0x00, 0x30);
                if (rc < 0)
                        return rc;

                rc = r820t_write_reg_mask(priv, 0x10, 0x00, 0x04);
                if (rc < 0)
                        return rc;
        }
        return 0;
}

static int r820t_set_tv_standard(struct r820t_priv *priv,
                                 unsigned bw,
                                 enum v4l2_tuner_type type,
                                 v4l2_std_id std, u32 delsys)

{
        int rc, i;
        u32 if_khz, filt_cal_lo;
        u8 data[5], val;
        u8 filt_gain, img_r, filt_q, hp_cor, ext_enable, loop_through;
        u8 lt_att, flt_ext_widest, polyfil_cur;
        bool need_calibration;

        tuner_dbg("selecting the delivery system\n");

        if (delsys == SYS_ISDBT) {
                if_khz = 4063;
                filt_cal_lo = 59000;
                filt_gain = 0x10;       /* +3db, 6mhz on */
                img_r = 0x00;           /* image negative */
                filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                hp_cor = 0x6a;          /* 1.7m disable, +2cap, 1.25mhz */
                ext_enable = 0x40;      /* r30[6], ext enable; r30[5]:0 ext at lna max */
                loop_through = 0x00;    /* r5[7], lt on */
                lt_att = 0x00;          /* r31[7], lt att enable */
                flt_ext_widest = 0x80;  /* r15[7]: flt_ext_wide on */
                polyfil_cur = 0x60;     /* r25[6:5]:min */
        } else if (delsys == SYS_DVBC_ANNEX_A) {
                if_khz = 5070;
                filt_cal_lo = 73500;
                filt_gain = 0x10;       /* +3db, 6mhz on */
                img_r = 0x00;           /* image negative */
                filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                hp_cor = 0x0b;          /* 1.7m disable, +0cap, 1.0mhz */
                ext_enable = 0x40;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                loop_through = 0x00;    /* r5[7], lt on */
                lt_att = 0x00;          /* r31[7], lt att enable */
                flt_ext_widest = 0x00;  /* r15[7]: flt_ext_wide off */
                polyfil_cur = 0x60;     /* r25[6:5]:min */
        } else if (delsys == SYS_DVBC_ANNEX_C) {
                if_khz = 4063;
                filt_cal_lo = 55000;
                filt_gain = 0x10;       /* +3db, 6mhz on */
                img_r = 0x00;           /* image negative */
                filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                hp_cor = 0x6a;          /* 1.7m disable, +0cap, 1.0mhz */
                ext_enable = 0x40;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                loop_through = 0x00;    /* r5[7], lt on */
                lt_att = 0x00;          /* r31[7], lt att enable */
                flt_ext_widest = 0x80;  /* r15[7]: flt_ext_wide on */
                polyfil_cur = 0x60;     /* r25[6:5]:min */
        } else {
                if (bw <= 6) {
                        if_khz = 3570;
                        filt_cal_lo = 56000;    /* 52000->56000 */
                        filt_gain = 0x10;       /* +3db, 6mhz on */
                        img_r = 0x00;           /* image negative */
                        filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                        hp_cor = 0x6b;          /* 1.7m disable, +2cap, 1.0mhz */
                        ext_enable = 0x60;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                        loop_through = 0x00;    /* r5[7], lt on */
                        lt_att = 0x00;          /* r31[7], lt att enable */
                        flt_ext_widest = 0x00;  /* r15[7]: flt_ext_wide off */
                        polyfil_cur = 0x60;     /* r25[6:5]:min */
                } else if (bw == 7) {
#if 0
                        /*
                         * There are two 7 MHz tables defined on the original
                         * driver, but just the second one seems to be visible
                         * by rtl2832. Keep this one here commented, as it
                         * might be needed in the future
                         */

                        if_khz = 4070;

                        filt_cal_lo = 60000;
                        filt_gain = 0x10;       /* +3db, 6mhz on */
                        img_r = 0x00;           /* image negative */
                        filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                        hp_cor = 0x2b;          /* 1.7m disable, +1cap, 1.0mhz */
                        ext_enable = 0x60;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                        loop_through = 0x00;    /* r5[7], lt on */
                        lt_att = 0x00;          /* r31[7], lt att enable */
                        flt_ext_widest = 0x00;  /* r15[7]: flt_ext_wide off */
                        polyfil_cur = 0x60;     /* r25[6:5]:min */
#endif
                        /* 7 MHz, second table */
                        if_khz = 4570;
                        filt_cal_lo = 63000;
                        filt_gain = 0x10;       /* +3db, 6mhz on */
                        img_r = 0x00;           /* image negative */
                        filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                        hp_cor = 0x2a;          /* 1.7m disable, +1cap, 1.25mhz */
                        ext_enable = 0x60;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                        loop_through = 0x00;    /* r5[7], lt on */
                        lt_att = 0x00;          /* r31[7], lt att enable */
                        flt_ext_widest = 0x00;  /* r15[7]: flt_ext_wide off */
                        polyfil_cur = 0x60;     /* r25[6:5]:min */
                } else {
                        if_khz = 4570;
                        filt_cal_lo = 68500;
                        filt_gain = 0x10;       /* +3db, 6mhz on */
                        img_r = 0x00;           /* image negative */
                        filt_q = 0x10;          /* r10[4]:low q(1'b1) */
                        hp_cor = 0x0b;          /* 1.7m disable, +0cap, 1.0mhz */
                        ext_enable = 0x60;      /* r30[6]=1 ext enable; r30[5]:1 ext at lna max-1 */
                        loop_through = 0x00;    /* r5[7], lt on */
                        lt_att = 0x00;          /* r31[7], lt att enable */
                        flt_ext_widest = 0x00;  /* r15[7]: flt_ext_wide off */
                        polyfil_cur = 0x60;     /* r25[6:5]:min */
                }
        }

        /* Initialize the shadow registers */
        memcpy(priv->regs, r820t_init_array, sizeof(r820t_init_array));

        /* Init Flag & Xtal_check Result */
        if (priv->imr_done)
                val = 1 | priv->xtal_cap_sel << 1;
        else
                val = 0;
        rc = r820t_write_reg_mask(priv, 0x0c, val, 0x0f);
        if (rc < 0)
                return rc;

        /* version */
        rc = r820t_write_reg_mask(priv, 0x13, VER_NUM, 0x3f);
        if (rc < 0)
                return rc;

        /* for LT Gain test */
        if (type != V4L2_TUNER_ANALOG_TV) {
                rc = r820t_write_reg_mask(priv, 0x1d, 0x00, 0x38);
                if (rc < 0)
                        return rc;
                usleep_range(1000, 2000);
        }
        priv->int_freq = if_khz * 1000;

        /* Check if standard changed. If so, filter calibration is needed */
        if (type != priv->type)
                need_calibration = true;
        else if ((type == V4L2_TUNER_ANALOG_TV) && (std != priv->std))
                need_calibration = true;
        else if ((type == V4L2_TUNER_DIGITAL_TV) &&
                 ((delsys != priv->delsys) || bw != priv->bw))
                need_calibration = true;
        else
                need_calibration = false;

        if (need_calibration) {
                tuner_dbg("calibrating the tuner\n");
                for (i = 0; i < 2; i++) {
                        /* Set filt_cap */
                        rc = r820t_write_reg_mask(priv, 0x0b, hp_cor, 0x60);
                        if (rc < 0)
                                return rc;

                        /* set cali clk =on */
                        rc = r820t_write_reg_mask(priv, 0x0f, 0x04, 0x04);
                        if (rc < 0)
                                return rc;

                        /* X'tal cap 0pF for PLL */
                        rc = r820t_write_reg_mask(priv, 0x10, 0x00, 0x03);
                        if (rc < 0)
                                return rc;

                        rc = r820t_set_pll(priv, type, filt_cal_lo * 1000);
                        if (rc < 0 || !priv->has_lock)
                                return rc;

                        /* Start Trigger */
                        rc = r820t_write_reg_mask(priv, 0x0b, 0x10, 0x10);
                        if (rc < 0)
                                return rc;

                        usleep_range(1000, 2000);

                        /* Stop Trigger */
                        rc = r820t_write_reg_mask(priv, 0x0b, 0x00, 0x10);
                        if (rc < 0)
                                return rc;

                        /* set cali clk =off */
                        rc = r820t_write_reg_mask(priv, 0x0f, 0x00, 0x04);
                        if (rc < 0)
                                return rc;

                        /* Check if calibration worked */
                        rc = r820t_read(priv, 0x00, data, sizeof(data));
                        if (rc < 0)
                                return rc;

                        priv->fil_cal_code = data[4] & 0x0f;
                        if (priv->fil_cal_code && priv->fil_cal_code != 0x0f)
                                break;
                }
                /* narrowest */
                if (priv->fil_cal_code == 0x0f)
                        priv->fil_cal_code = 0;
        }

        rc = r820t_write_reg_mask(priv, 0x0a,
                                  filt_q | priv->fil_cal_code, 0x1f);
        if (rc < 0)
                return rc;

        /* Set BW, Filter_gain, & HP corner */
        rc = r820t_write_reg_mask(priv, 0x0b, hp_cor, 0xef);
        if (rc < 0)
                return rc;


        /* Set Img_R */
        rc = r820t_write_reg_mask(priv, 0x07, img_r, 0x80);
        if (rc < 0)
                return rc;

        /* Set filt_3dB, V6MHz */
        rc = r820t_write_reg_mask(priv, 0x06, filt_gain, 0x30);
        if (rc < 0)
                return rc;

        /* channel filter extension */
        rc = r820t_write_reg_mask(priv, 0x1e, ext_enable, 0x60);
        if (rc < 0)
                return rc;

        /* Loop through */
        rc = r820t_write_reg_mask(priv, 0x05, loop_through, 0x80);
        if (rc < 0)
                return rc;

        /* Loop through attenuation */
        rc = r820t_write_reg_mask(priv, 0x1f, lt_att, 0x80);
        if (rc < 0)
                return rc;

        /* filter extension widest */
        rc = r820t_write_reg_mask(priv, 0x0f, flt_ext_widest, 0x80);
        if (rc < 0)
                return rc;

        /* RF poly filter current */
        rc = r820t_write_reg_mask(priv, 0x19, polyfil_cur, 0x60);
        if (rc < 0)
                return rc;

        /* Store current standard. If it changes, re-calibrate the tuner */
        priv->delsys = delsys;
        priv->type = type;
        priv->std = std;
        priv->bw = bw;

        return 0;
}

static int r820t_read_gain(struct r820t_priv *priv)
{
        u8 data[4];
        int rc;

        rc = r820t_read(priv, 0x00, data, sizeof(data));
        if (rc < 0)
                return rc;

        return ((data[3] & 0x08) << 1) + ((data[3] & 0xf0) >> 4);
}

#if 0
/* FIXME: This routine requires more testing */

/*
 * measured with a Racal 6103E GSM test set at 928 MHz with -60 dBm
 * input power, for raw results see:
 *      http://steve-m.de/projects/rtl-sdr/gain_measurement/r820t/
 */

static const int r820t_lna_gain_steps[]  = {
        0, 9, 13, 40, 38, 13, 31, 22, 26, 31, 26, 14, 19, 5, 35, 13
};

static const int r820t_mixer_gain_steps[]  = {
        0, 5, 10, 10, 19, 9, 10, 25, 17, 10, 8, 16, 13, 6, 3, -8
};

static int r820t_set_gain_mode(struct r820t_priv *priv,
                               bool set_manual_gain,
                               int gain)
{
        int rc;

        if (set_manual_gain) {
                int i, total_gain = 0;
                uint8_t mix_index = 0, lna_index = 0;
                u8 data[4];

                /* LNA auto off */
                rc = r820t_write_reg_mask(priv, 0x05, 0x10, 0x10);
                if (rc < 0)
                        return rc;

                 /* Mixer auto off */
                rc = r820t_write_reg_mask(priv, 0x07, 0, 0x10);
                if (rc < 0)
                        return rc;

                rc = r820t_read(priv, 0x00, data, sizeof(data));
                if (rc < 0)
                        return rc;

                /* set fixed VGA gain for now (16.3 dB) */
                rc = r820t_write_reg_mask(priv, 0x0c, 0x08, 0x9f);
                if (rc < 0)
                        return rc;

                for (i = 0; i < 15; i++) {
                        if (total_gain >= gain)
                                break;

                        total_gain += r820t_lna_gain_steps[++lna_index];

                        if (total_gain >= gain)
                                break;

                        total_gain += r820t_mixer_gain_steps[++mix_index];
                }

                /* set LNA gain */
                rc = r820t_write_reg_mask(priv, 0x05, lna_index, 0x0f);
                if (rc < 0)
                        return rc;

                /* set Mixer gain */
                rc = r820t_write_reg_mask(priv, 0x07, mix_index, 0x0f);
                if (rc < 0)
                        return rc;
        } else {
                /* LNA */
                rc = r820t_write_reg_mask(priv, 0x05, 0, 0x10);
                if (rc < 0)
                        return rc;

                /* Mixer */
                rc = r820t_write_reg_mask(priv, 0x07, 0x10, 0x10);
                if (rc < 0)
                        return rc;

                /* set fixed VGA gain for now (26.5 dB) */
                rc = r820t_write_reg_mask(priv, 0x0c, 0x0b, 0x9f);
                if (rc < 0)
                        return rc;
        }

        return 0;
}
#endif

static int generic_set_freq(struct dvb_frontend *fe,
                            u32 freq /* in HZ */,
                            unsigned bw,
                            enum v4l2_tuner_type type,
                            v4l2_std_id std, u32 delsys)
{
        struct r820t_priv               *priv = fe->tuner_priv;
        int                             rc;
        u32                             lo_freq;

        tuner_dbg("should set frequency to %d kHz, bw %d MHz\n",
                  freq / 1000, bw);

        rc = r820t_set_tv_standard(priv, bw, type, std, delsys);
        if (rc < 0)
                goto err;

        if ((type == V4L2_TUNER_ANALOG_TV) && (std == V4L2_STD_SECAM_LC))
                lo_freq = freq - priv->int_freq;
         else
                lo_freq = freq + priv->int_freq;

        rc = r820t_set_mux(priv, lo_freq);
        if (rc < 0)
                goto err;

        rc = r820t_set_pll(priv, type, lo_freq);
        if (rc < 0 || !priv->has_lock)
                goto err;

        rc = r820t_sysfreq_sel(priv, freq, type, std, delsys);
        if (rc < 0)
                goto err;

        tuner_dbg("%s: PLL locked on frequency %d Hz, gain=%d\n",
                  __func__, freq, r820t_read_gain(priv));

err:

        if (rc < 0)
                tuner_dbg("%s: failed=%d\n", __func__, rc);
        return rc;
}

/*
 * r820t standby logic
 */

static int r820t_standby(struct r820t_priv *priv)
{
        int rc;

        /* If device was not initialized yet, don't need to standby */
        if (!priv->init_done)
                return 0;

        rc = r820t_write_reg(priv, 0x06, 0xb1);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x05, 0x03);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x07, 0x3a);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x08, 0x40);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x09, 0xc0);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x0a, 0x36);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x0c, 0x35);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x0f, 0x68);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x11, 0x03);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x17, 0xf4);
        if (rc < 0)
                return rc;
        rc = r820t_write_reg(priv, 0x19, 0x0c);

        /* Force initial calibration */
        priv->type = -1;

        return rc;
}

/*
 * r820t device init logic
 */

static int r820t_xtal_check(struct r820t_priv *priv)
{
        int rc, i;
        u8 data[3], val;

        /* Initialize the shadow registers */
        memcpy(priv->regs, r820t_init_array, sizeof(r820t_init_array));

        /* cap 30pF & Drive Low */
        rc = r820t_write_reg_mask(priv, 0x10, 0x0b, 0x0b);
        if (rc < 0)
                return rc;

        /* set pll autotune = 128kHz */
        rc = r820t_write_reg_mask(priv, 0x1a, 0x00, 0x0c);
        if (rc < 0)
                return rc;

        /* set manual initial reg = 111111;  */
        rc = r820t_write_reg_mask(priv, 0x13, 0x7f, 0x7f);
        if (rc < 0)
                return rc;

        /* set auto */
        rc = r820t_write_reg_mask(priv, 0x13, 0x00, 0x40);
        if (rc < 0)
                return rc;

        /* Try several xtal capacitor alternatives */
        for (i = 0; i < ARRAY_SIZE(r820t_xtal_capacitor); i++) {
                rc = r820t_write_reg_mask(priv, 0x10,
                                          r820t_xtal_capacitor[i][0], 0x1b);
                if (rc < 0)
                        return rc;

                usleep_range(5000, 6000);

                rc = r820t_read(priv, 0x00, data, sizeof(data));
                if (rc < 0)
                        return rc;
                if (!(data[2] & 0x40))
                        continue;

                val = data[2] & 0x3f;

                if (priv->cfg->xtal == 16000000 && (val > 29 || val < 23))
                        break;

                if (val != 0x3f)
                        break;
        }

        if (i == ARRAY_SIZE(r820t_xtal_capacitor))
                return -EINVAL;

        return r820t_xtal_capacitor[i][1];
}

static int r820t_imr_prepare(struct r820t_priv *priv)
{
        int rc;

        /* Initialize the shadow registers */
        memcpy(priv->regs, r820t_init_array, sizeof(r820t_init_array));

        /* lna off (air-in off) */
        rc = r820t_write_reg_mask(priv, 0x05, 0x20, 0x20);
        if (rc < 0)
                return rc;

        /* mixer gain mode = manual */
        rc = r820t_write_reg_mask(priv, 0x07, 0, 0x10);
        if (rc < 0)
                return rc;

        /* filter corner = lowest */
        rc = r820t_write_reg_mask(priv, 0x0a, 0x0f, 0x0f);
        if (rc < 0)
                return rc;

        /* filter bw=+2cap, hp=5M */
        rc = r820t_write_reg_mask(priv, 0x0b, 0x60, 0x6f);
        if (rc < 0)
                return rc;

        /* adc=on, vga code mode, gain = 26.5dB   */
        rc = r820t_write_reg_mask(priv, 0x0c, 0x0b, 0x9f);
        if (rc < 0)
                return rc;

        /* ring clk = on */
        rc = r820t_write_reg_mask(priv, 0x0f, 0, 0x08);
        if (rc < 0)
                return rc;

        /* ring power = on */
        rc = r820t_write_reg_mask(priv, 0x18, 0x10, 0x10);
        if (rc < 0)
                return rc;

        /* from ring = ring pll in */
        rc = r820t_write_reg_mask(priv, 0x1c, 0x02, 0x02);
        if (rc < 0)
                return rc;

        /* sw_pdect = det3 */
        rc = r820t_write_reg_mask(priv, 0x1e, 0x80, 0x80);
        if (rc < 0)
                return rc;

        /* Set filt_3dB */
        rc = r820t_write_reg_mask(priv, 0x06, 0x20, 0x20);

        return rc;
}

static int r820t_multi_read(struct r820t_priv *priv)
{
        int rc, i;
        u16 sum = 0;
        u8 data[2], min = 255, max = 0;

        usleep_range(5000, 6000);

        for (i = 0; i < 6; i++) {
                rc = r820t_read(priv, 0x00, data, sizeof(data));
                if (rc < 0)
                        return rc;

                sum += data[1];

                if (data[1] < min)
                        min = data[1];

                if (data[1] > max)
                        max = data[1];
        }
        rc = sum - max - min;

        return rc;
}

static int r820t_imr_cross(struct r820t_priv *priv,
                           struct r820t_sect_type iq_point[3],
                           u8 *x_direct)
{
        struct r820t_sect_type cross[5]; /* (0,0)(0,Q-1)(0,I-1)(Q-1,0)(I-1,0) */
        struct r820t_sect_type tmp;
        int i, rc;
        u8 reg08, reg09;

        reg08 = r820t_read_cache_reg(priv, 8) & 0xc0;
        reg09 = r820t_read_cache_reg(priv, 9) & 0xc0;

        tmp.gain_x = 0;
        tmp.phase_y = 0;
        tmp.value = 255;

        for (i = 0; i < 5; i++) {
                switch (i) {
                case 0:
                        cross[i].gain_x  = reg08;
                        cross[i].phase_y = reg09;
                        break;
                case 1:
                        cross[i].gain_x  = reg08;               /* 0 */
                        cross[i].phase_y = reg09 + 1;           /* Q-1 */
                        break;
                case 2:
                        cross[i].gain_x  = reg08;               /* 0 */
                        cross[i].phase_y = (reg09 | 0x20) + 1;  /* I-1 */
                        break;
                case 3:
                        cross[i].gain_x  = reg08 + 1;           /* Q-1 */
                        cross[i].phase_y = reg09;
                        break;
                default:
                        cross[i].gain_x  = (reg08 | 0x20) + 1;  /* I-1 */
                        cross[i].phase_y = reg09;
                }

                rc = r820t_write_reg(priv, 0x08, cross[i].gain_x);
                if (rc < 0)
                        return rc;

                rc = r820t_write_reg(priv, 0x09, cross[i].phase_y);
                if (rc < 0)
                        return rc;

                rc = r820t_multi_read(priv);
                if (rc < 0)
                        return rc;

                cross[i].value = rc;

                if (cross[i].value < tmp.value)
                        tmp = cross[i];
        }

        if ((tmp.phase_y & 0x1f) == 1) {        /* y-direction */
                *x_direct = 0;

                iq_point[0] = cross[0];
                iq_point[1] = cross[1];
                iq_point[2] = cross[2];
        } else {                                /* (0,0) or x-direction */
                *x_direct = 1;

                iq_point[0] = cross[0];
                iq_point[1] = cross[3];
                iq_point[2] = cross[4];
        }
        return 0;
}

static void r820t_compre_cor(struct r820t_sect_type iq[3])
{
        int i;

        for (i = 3; i > 0; i--) {
                if (iq[0].value > iq[i - 1].value)
                        swap(iq[0], iq[i - 1]);
        }
}

static int r820t_compre_step(struct r820t_priv *priv,
                             struct r820t_sect_type iq[3], u8 reg)
{
        int rc;
        struct r820t_sect_type tmp;

        /*
         * Purpose: if (Gain<9 or Phase<9), Gain+1 or Phase+1 and compare
         * with min value:
         *  new < min => update to min and continue
         *  new > min => Exit
         */

        /* min value already saved in iq[0] */
        tmp.phase_y = iq[0].phase_y;
        tmp.gain_x  = iq[0].gain_x;

        while (((tmp.gain_x & 0x1f) < IMR_TRIAL) &&
              ((tmp.phase_y & 0x1f) < IMR_TRIAL)) {
                if (reg == 0x08)
                        tmp.gain_x++;
                else
                        tmp.phase_y++;

                rc = r820t_write_reg(priv, 0x08, tmp.gain_x);
                if (rc < 0)
                        return rc;

                rc = r820t_write_reg(priv, 0x09, tmp.phase_y);
                if (rc < 0)
                        return rc;

                rc = r820t_multi_read(priv);
                if (rc < 0)
                        return rc;
                tmp.value = rc;

                if (tmp.value <= iq[0].value) {
                        iq[0].gain_x  = tmp.gain_x;
                        iq[0].phase_y = tmp.phase_y;
                        iq[0].value   = tmp.value;
                } else {
                        return 0;
                }

        }

        return 0;
}

static int r820t_iq_tree(struct r820t_priv *priv,
                         struct r820t_sect_type iq[3],
                         u8 fix_val, u8 var_val, u8 fix_reg)
{
        int rc, i;
        u8 tmp, var_reg;

        /*
         * record IMC results by input gain/phase location then adjust
         * gain or phase positive 1 step and negative 1 step,
         * both record results
         */

        if (fix_reg == 0x08)
                var_reg = 0x09;
        else
                var_reg = 0x08;

        for (i = 0; i < 3; i++) {
                rc = r820t_write_reg(priv, fix_reg, fix_val);
                if (rc < 0)
                        return rc;

                rc = r820t_write_reg(priv, var_reg, var_val);
                if (rc < 0)
                        return rc;

                rc = r820t_multi_read(priv);
                if (rc < 0)
                        return rc;
                iq[i].value = rc;

                if (fix_reg == 0x08) {
                        iq[i].gain_x  = fix_val;
                        iq[i].phase_y = var_val;
                } else {
                        iq[i].phase_y = fix_val;
                        iq[i].gain_x  = var_val;
                }

                if (i == 0) {  /* try right-side point */
                        var_val++;
                } else if (i == 1) { /* try left-side point */
                         /* if absolute location is 1, change I/Q direction */
                        if ((var_val & 0x1f) < 0x02) {
                                tmp = 2 - (var_val & 0x1f);

                                /* b[5]:I/Q selection. 0:Q-path, 1:I-path */
                                if (var_val & 0x20) {
                                        var_val &= 0xc0;
                                        var_val |= tmp;
                                } else {
                                        var_val |= 0x20 | tmp;
                                }
                        } else {
                                var_val -= 2;
                        }
                }
        }

        return 0;
}

static int r820t_section(struct r820t_priv *priv,
                         struct r820t_sect_type *iq_point)
{
        int rc;
        struct r820t_sect_type compare_iq[3], compare_bet[3];

        /* Try X-1 column and save min result to compare_bet[0] */
        if (!(iq_point->gain_x & 0x1f))
                compare_iq[0].gain_x = ((iq_point->gain_x) & 0xdf) + 1;  /* Q-path, Gain=1 */
        else
                compare_iq[0].gain_x  = iq_point->gain_x - 1;  /* left point */
        compare_iq[0].phase_y = iq_point->phase_y;

        /* y-direction */
        rc = r820t_iq_tree(priv, compare_iq,  compare_iq[0].gain_x,
                        compare_iq[0].phase_y, 0x08);
        if (rc < 0)
                return rc;

        r820t_compre_cor(compare_iq);

        compare_bet[0] = compare_iq[0];

        /* Try X column and save min result to compare_bet[1] */
        compare_iq[0].gain_x  = iq_point->gain_x;
        compare_iq[0].phase_y = iq_point->phase_y;

        rc = r820t_iq_tree(priv, compare_iq,  compare_iq[0].gain_x,
                           compare_iq[0].phase_y, 0x08);
        if (rc < 0)
                return rc;

        r820t_compre_cor(compare_iq);

        compare_bet[1] = compare_iq[0];

        /* Try X+1 column and save min result to compare_bet[2] */
        if ((iq_point->gain_x & 0x1f) == 0x00)
                compare_iq[0].gain_x = ((iq_point->gain_x) | 0x20) + 1;  /* I-path, Gain=1 */
        else
                compare_iq[0].gain_x = iq_point->gain_x + 1;
        compare_iq[0].phase_y = iq_point->phase_y;

        rc = r820t_iq_tree(priv, compare_iq,  compare_iq[0].gain_x,
                           compare_iq[0].phase_y, 0x08);
        if (rc < 0)
                return rc;

        r820t_compre_cor(compare_iq);

        compare_bet[2] = compare_iq[0];

        r820t_compre_cor(compare_bet);

        *iq_point = compare_bet[0];

        return 0;
}

static int r820t_vga_adjust(struct r820t_priv *priv)
{
        int rc;
        u8 vga_count;

        /* increase vga power to let image significant */
        for (vga_count = 12; vga_count < 16; vga_count++) {
                rc = r820t_write_reg_mask(priv, 0x0c, vga_count, 0x0f);
                if (rc < 0)
                        return rc;

                usleep_range(10000, 11000);

                rc = r820t_multi_read(priv);
                if (rc < 0)
                        return rc;

                if (rc > 40 * 4)
                        break;
        }

        return 0;
}

static int r820t_iq(struct r820t_priv *priv, struct r820t_sect_type *iq_pont)
{
        struct r820t_sect_type compare_iq[3];
        int rc;
        u8 x_direction = 0;  /* 1:x, 0:y */
        u8 dir_reg, other_reg;

        r820t_vga_adjust(priv);

        rc = r820t_imr_cross(priv, compare_iq, &x_direction);
        if (rc < 0)
                return rc;

        if (x_direction == 1) {
                dir_reg   = 0x08;
                other_reg = 0x09;
        } else {
                dir_reg   = 0x09;
                other_reg = 0x08;
        }

        /* compare and find min of 3 points. determine i/q direction */
        r820t_compre_cor(compare_iq);

        /* increase step to find min value of this direction */
        rc = r820t_compre_step(priv, compare_iq, dir_reg);
        if (rc < 0)
                return rc;

        /* the other direction */
        rc = r820t_iq_tree(priv, compare_iq,  compare_iq[0].gain_x,
                                compare_iq[0].phase_y, dir_reg);
        if (rc < 0)
                return rc;

        /* compare and find min of 3 points. determine i/q direction */
        r820t_compre_cor(compare_iq);

        /* increase step to find min value on this direction */
        rc = r820t_compre_step(priv, compare_iq, other_reg);
        if (rc < 0)
                return rc;

        /* check 3 points again */
        rc = r820t_iq_tree(priv, compare_iq,  compare_iq[0].gain_x,
                                compare_iq[0].phase_y, other_reg);
        if (rc < 0)
                return rc;

        r820t_compre_cor(compare_iq);

        /* section-9 check */
        rc = r820t_section(priv, compare_iq);

        *iq_pont = compare_iq[0];

        /* reset gain/phase control setting */
        rc = r820t_write_reg_mask(priv, 0x08, 0, 0x3f);
        if (rc < 0)
                return rc;

        rc = r820t_write_reg_mask(priv, 0x09, 0, 0x3f);

        return rc;
}

static int r820t_f_imr(struct r820t_priv *priv, struct r820t_sect_type *iq_pont)
{
        int rc;

        r820t_vga_adjust(priv);

        /*
         * search surrounding points from previous point
         * try (x-1), (x), (x+1) columns, and find min IMR result point
         */
        rc = r820t_section(priv, iq_pont);
        if (rc < 0)
                return rc;

        return 0;
}

static int r820t_imr(struct r820t_priv *priv, unsigned imr_mem, bool im_flag)
{
        struct r820t_sect_type imr_point;
        int rc;
        u32 ring_vco, ring_freq, ring_ref;
        u8 n_ring, n;
        int reg18, reg19, reg1f;

        if (priv->cfg->xtal > 24000000)
                ring_ref = priv->cfg->xtal / 2000;
        else
                ring_ref = priv->cfg->xtal / 1000;

        n_ring = 15;
        for (n = 0; n < 16; n++) {
                if ((16 + n) * 8 * ring_ref >= 3100000) {
                        n_ring = n;
                        break;
                }
        }

        reg18 = r820t_read_cache_reg(priv, 0x18);
        reg19 = r820t_read_cache_reg(priv, 0x19);
        reg1f = r820t_read_cache_reg(priv, 0x1f);

        reg18 &= 0xf0;      /* set ring[3:0] */
        reg18 |= n_ring;

        ring_vco = (16 + n_ring) * 8 * ring_ref;

        reg18 &= 0xdf;   /* clear ring_se23 */
        reg19 &= 0xfc;   /* clear ring_seldiv */
        reg1f &= 0xfc;   /* clear ring_att */

        switch (imr_mem) {
        case 0:
                ring_freq = ring_vco / 48;
                reg18 |= 0x20;  /* ring_se23 = 1 */
                reg19 |= 0x03;  /* ring_seldiv = 3 */
                reg1f |= 0x02;  /* ring_att 10 */
                break;
        case 1:
                ring_freq = ring_vco / 16;
                reg18 |= 0x00;  /* ring_se23 = 0 */
                reg19 |= 0x02;  /* ring_seldiv = 2 */
                reg1f |= 0x00;  /* pw_ring 00 */
                break;
        case 2:
                ring_freq = ring_vco / 8;
                reg18 |= 0x00;  /* ring_se23 = 0 */
                reg19 |= 0x01;  /* ring_seldiv = 1 */
                reg1f |= 0x03;  /* pw_ring 11 */
                break;
        case 3:
                ring_freq = ring_vco / 6;
                reg18 |= 0x20;  /* ring_se23 = 1 */
                reg19 |= 0x00;  /* ring_seldiv = 0 */
                reg1f |= 0x03;  /* pw_ring 11 */
                break;
        case 4:
                ring_freq = ring_vco / 4;
                reg18 |= 0x00;  /* ring_se23 = 0 */
                reg19 |= 0x00;  /* ring_seldiv = 0 */
                reg1f |= 0x01;  /* pw_ring 01 */
                break;
        default:
                ring_freq = ring_vco / 4;
                reg18 |= 0x00;  /* ring_se23 = 0 */
                reg19 |= 0x00;  /* ring_seldiv = 0 */
                reg1f |= 0x01;  /* pw_ring 01 */
                break;
        }


        /* write pw_ring, n_ring, ringdiv2 registers */

        /* n_ring, ring_se23 */
        rc = r820t_write_reg(priv, 0x18, reg18);
        if (rc < 0)
                return rc;

        /* ring_sediv */
        rc = r820t_write_reg(priv, 0x19, reg19);
        if (rc < 0)
                return rc;

        /* pw_ring */
        rc = r820t_write_reg(priv, 0x1f, reg1f);
        if (rc < 0)
                return rc;

        /* mux input freq ~ rf_in freq */
        rc = r820t_set_mux(priv, (ring_freq - 5300) * 1000);
        if (rc < 0)
                return rc;

        rc = r820t_set_pll(priv, V4L2_TUNER_DIGITAL_TV,
                           (ring_freq - 5300) * 1000);
        if (!priv->has_lock)
                rc = -EINVAL;
        if (rc < 0)
                return rc;

        if (im_flag) {
                rc = r820t_iq(priv, &imr_point);
        } else {
                imr_point.gain_x  = priv->imr_data[3].gain_x;
                imr_point.phase_y = priv->imr_data[3].phase_y;
                imr_point.value   = priv->imr_data[3].value;

                rc = r820t_f_imr(priv, &imr_point);
        }
        if (rc < 0)
                return rc;

        /* save IMR value */
        switch (imr_mem) {
        case 0:
                priv->imr_data[0].gain_x  = imr_point.gain_x;
                priv->imr_data[0].phase_y = imr_point.phase_y;
                priv->imr_data[0].value   = imr_point.value;
                break;
        case 1:
                priv->imr_data[1].gain_x  = imr_point.gain_x;
                priv->imr_data[1].phase_y = imr_point.phase_y;
                priv->imr_data[1].value   = imr_point.value;
                break;
        case 2:
                priv->imr_data[2].gain_x  = imr_point.gain_x;
                priv->imr_data[2].phase_y = imr_point.phase_y;
                priv->imr_data[2].value   = imr_point.value;
                break;
        case 3:
                priv->imr_data[3].gain_x  = imr_point.gain_x;
                priv->imr_data[3].phase_y = imr_point.phase_y;
                priv->imr_data[3].value   = imr_point.value;
                break;
        case 4:
                priv->imr_data[4].gain_x  = imr_point.gain_x;
                priv->imr_data[4].phase_y = imr_point.phase_y;
                priv->imr_data[4].value   = imr_point.value;
                break;
        default:
                priv->imr_data[4].gain_x  = imr_point.gain_x;
                priv->imr_data[4].phase_y = imr_point.phase_y;
                priv->imr_data[4].value   = imr_point.value;
                break;
        }

        return 0;
}

static int r820t_imr_callibrate(struct r820t_priv *priv)
{
        int rc, i;
        int xtal_cap = 0;

        if (priv->init_done)
                return 0;

        /* Detect Xtal capacitance */
        if ((priv->cfg->rafael_chip == CHIP_R820T) ||
            (priv->cfg->rafael_chip == CHIP_R828S) ||
            (priv->cfg->rafael_chip == CHIP_R820C)) {
                priv->xtal_cap_sel = XTAL_HIGH_CAP_0P;
        } else {
                /* Initialize registers */
                rc = r820t_write(priv, 0x05,
                                r820t_init_array, sizeof(r820t_init_array));
                if (rc < 0)
                        return rc;
                for (i = 0; i < 3; i++) {
                        rc = r820t_xtal_check(priv);
                        if (rc < 0)
                                return rc;
                        if (!i || rc > xtal_cap)
                                xtal_cap = rc;
                }
                priv->xtal_cap_sel = xtal_cap;
        }

        /*
         * Disables IMR calibration. That emulates the same behaviour
         * as what is done by rtl-sdr userspace library. Useful for testing
         */
        if (no_imr_cal) {
                priv->init_done = true;

                return 0;
        }

        /* Initialize registers */
        rc = r820t_write(priv, 0x05,
                         r820t_init_array, sizeof(r820t_init_array));
        if (rc < 0)
                return rc;

        rc = r820t_imr_prepare(priv);
        if (rc < 0)
                return rc;

        rc = r820t_imr(priv, 3, true);
        if (rc < 0)
                return rc;
        rc = r820t_imr(priv, 1, false);
        if (rc < 0)
                return rc;
        rc = r820t_imr(priv, 0, false);
        if (rc < 0)
                return rc;
        rc = r820t_imr(priv, 2, false);
        if (rc < 0)
                return rc;
        rc = r820t_imr(priv, 4, false);
        if (rc < 0)
                return rc;

        priv->init_done = true;
        priv->imr_done = true;

        return 0;
}

#if 0
/* Not used, for now */
static int r820t_gpio(struct r820t_priv *priv, bool enable)
{
        return r820t_write_reg_mask(priv, 0x0f, enable ? 1 : 0, 0x01);
}
#endif

/*
 *  r820t frontend operations and tuner attach code
 *
 * All driver locks and i2c control are only in this part of the code
 */

static int r820t_init(struct dvb_frontend *fe)
{
        struct r820t_priv *priv = fe->tuner_priv;
        int rc;

        tuner_dbg("%s:\n", __func__);

        mutex_lock(&priv->lock);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        rc = r820t_imr_callibrate(priv);
        if (rc < 0)
                goto err;

        /* Initialize registers */
        rc = r820t_write(priv, 0x05,
                         r820t_init_array, sizeof(r820t_init_array));

err:
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        mutex_unlock(&priv->lock);

        if (rc < 0)
                tuner_dbg("%s: failed=%d\n", __func__, rc);
        return rc;
}

static int r820t_sleep(struct dvb_frontend *fe)
{
        struct r820t_priv *priv = fe->tuner_priv;
        int rc;

        tuner_dbg("%s:\n", __func__);

        mutex_lock(&priv->lock);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        rc = r820t_standby(priv);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        mutex_unlock(&priv->lock);

        tuner_dbg("%s: failed=%d\n", __func__, rc);
        return rc;
}

static int r820t_set_analog_freq(struct dvb_frontend *fe,
                                 struct analog_parameters *p)
{
        struct r820t_priv *priv = fe->tuner_priv;
        unsigned bw;
        int rc;

        tuner_dbg("%s called\n", __func__);

        /* if std is not defined, choose one */
        if (!p->std)
                p->std = V4L2_STD_MN;

        if ((p->std == V4L2_STD_PAL_M) || (p->std == V4L2_STD_NTSC))
                bw = 6;
        else
                bw = 8;

        mutex_lock(&priv->lock);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        rc = generic_set_freq(fe, 62500l * p->frequency, bw,
                              V4L2_TUNER_ANALOG_TV, p->std, SYS_UNDEFINED);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        mutex_unlock(&priv->lock);

        return rc;
}

static int r820t_set_params(struct dvb_frontend *fe)
{
        struct r820t_priv *priv = fe->tuner_priv;
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
        int rc;
        unsigned bw;

        tuner_dbg("%s: delivery_system=%d frequency=%d bandwidth_hz=%d\n",
                __func__, c->delivery_system, c->frequency, c->bandwidth_hz);

        mutex_lock(&priv->lock);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        bw = (c->bandwidth_hz + 500000) / 1000000;
        if (!bw)
                bw = 8;

        rc = generic_set_freq(fe, c->frequency, bw,
                              V4L2_TUNER_DIGITAL_TV, 0, c->delivery_system);

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        mutex_unlock(&priv->lock);

        if (rc)
                tuner_dbg("%s: failed=%d\n", __func__, rc);
        return rc;
}

static int r820t_signal(struct dvb_frontend *fe, u16 *strength)
{
        struct r820t_priv *priv = fe->tuner_priv;
        int rc = 0;

        mutex_lock(&priv->lock);
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        if (priv->has_lock) {
                rc = r820t_read_gain(priv);
                if (rc < 0)
                        goto err;

                /* A higher gain at LNA means a lower signal strength */
                *strength = (45 - rc) << 4 | 0xff;
                if (*strength == 0xff)
                        *strength = 0;
        } else {
                *strength = 0;
        }

err:
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);
        mutex_unlock(&priv->lock);

        tuner_dbg("%s: %s, gain=%d strength=%d\n",
                  __func__,
                  priv->has_lock ? "PLL locked" : "no signal",
                  rc, *strength);

        return 0;
}

static int r820t_get_if_frequency(struct dvb_frontend *fe, u32 *frequency)
{
        struct r820t_priv *priv = fe->tuner_priv;

        tuner_dbg("%s:\n", __func__);

        *frequency = priv->int_freq;

        return 0;
}

static void r820t_release(struct dvb_frontend *fe)
{
        struct r820t_priv *priv = fe->tuner_priv;

        tuner_dbg("%s:\n", __func__);

        mutex_lock(&r820t_list_mutex);

        if (priv)
                hybrid_tuner_release_state(priv);

        mutex_unlock(&r820t_list_mutex);

        fe->tuner_priv = NULL;
}

static const struct dvb_tuner_ops r820t_tuner_ops = {
        .info = {
                .name             = "Rafael Micro R820T",
                .frequency_min_hz =   42 * MHz,
                .frequency_max_hz = 1002 * MHz,
        },
        .init = r820t_init,
        .release = r820t_release,
        .sleep = r820t_sleep,
        .set_params = r820t_set_params,
        .set_analog_params = r820t_set_analog_freq,
        .get_if_frequency = r820t_get_if_frequency,
        .get_rf_strength = r820t_signal,
};

struct dvb_frontend *r820t_attach(struct dvb_frontend *fe,
                                  struct i2c_adapter *i2c,
                                  const struct r820t_config *cfg)
{
        struct r820t_priv *priv;
        int rc = -ENODEV;
        u8 data[5];
        int instance;

        mutex_lock(&r820t_list_mutex);

        instance = hybrid_tuner_request_state(struct r820t_priv, priv,
                                              hybrid_tuner_instance_list,
                                              i2c, cfg->i2c_addr,
                                              "r820t");
        switch (instance) {
        case 0:
                /* memory allocation failure */
                goto err_no_gate;
        case 1:
                /* new tuner instance */
                priv->cfg = cfg;

                mutex_init(&priv->lock);

                fe->tuner_priv = priv;
                break;
        case 2:
                /* existing tuner instance */
                fe->tuner_priv = priv;
                break;
        }

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 1);

        /* check if the tuner is there */
        rc = r820t_read(priv, 0x00, data, sizeof(data));
        if (rc < 0)
                goto err;

        rc = r820t_sleep(fe);
        if (rc < 0)
                goto err;

        tuner_info("Rafael Micro r820t successfully identified\n");

        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

        mutex_unlock(&r820t_list_mutex);

        memcpy(&fe->ops.tuner_ops, &r820t_tuner_ops,
                        sizeof(struct dvb_tuner_ops));

        return fe;
err:
        if (fe->ops.i2c_gate_ctrl)
                fe->ops.i2c_gate_ctrl(fe, 0);

err_no_gate:
        mutex_unlock(&r820t_list_mutex);

        pr_info("%s: failed=%d\n", __func__, rc);
        r820t_release(fe);
        return NULL;
}
EXPORT_SYMBOL_GPL(r820t_attach);

MODULE_DESCRIPTION("Rafael Micro r820t silicon tuner driver");
MODULE_AUTHOR("Mauro Carvalho Chehab");
MODULE_LICENSE("GPL v2");