drivers/media/tuners/r820t.c

/*
 * Rafael Micro R820T driver
 *
 * Copyright (C) 2013 Mauro Carvalho Chehab <mchehab@redhat.com>
 *
 * 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.
 *
 *    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.
 *
 */

#include <linux/videodev2.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include "tuner-i2c.h"
#include <asm/div64.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 VER_NUM  49

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

/*
 * 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_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;

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

	bool				has_lock;
};

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

/*
 * 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)
		len = NUM_REGS;

	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 int r820t_write_reg(struct r820t_priv *priv, u8 reg, u8 val)
{
	return r820t_write(priv, reg, &val, 1);
}

static int r820t_write_reg_mask(struct r820t_priv *priv, u8 reg, u8 val,
				u8 bit_mask)
{
	int r = reg - REG_SHADOW_START;

	if (r >= 0 && r < NUM_REGS)
		val = (priv->regs[r] & ~bit_mask) | (val & bit_mask);
	else
		return -EINVAL;

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

static int r820_read(struct r820t_priv *priv, u8 reg, u8 *val, int len)
{
	int rc;
	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;
	}
	tuner_dbg("%s: i2c rd reg=%02x len=%d: %*ph\n",
		  __func__, reg, len, len, p);

	/* Copy data to the output buffer */
	memcpy(val, p, len);

	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;

	/* 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;

	/*
	 * FIXME: the original driver has a logic there with preserves
	 * gain/phase from registers 8 and 9 reading the data from the
	 * registers before writing, if "IMF done". That code was sort of
	 * commented there, as the flag is always false.
	 */
	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_set_pll(struct r820t_priv *priv, u32 freq)
{
	u64 tmp64, vco_freq;
	int rc, i;
	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 ni, si, nint, vco_fine_tune, val;
	u8 data[5];

	freq = freq / 1000;	/* Frequency in kHz */

	pll_ref = priv->cfg->xtal / 1000;

	tuner_dbg("set r820t pll for frequency %d kHz = %d\n", freq, pll_ref);

	/* FIXME: this seems to be a hack - probably it can be removed */
	rc = r820t_write_reg_mask(priv, 0x10, 0x00, 0x00);
	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 = r820_read(priv, 0x00, data, sizeof(data));
	if (rc < 0)
		return rc;

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

	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 = (u64)(freq * (u64)mix_div);

	tmp64 = vco_freq;
	do_div(tmp64, 2 * pll_ref);
	nint = (u8)tmp64;

	tmp64 = vco_freq - ((u64)2) * pll_ref * nint;
	do_div(tmp64, 1000);
	vco_fra  = (u16)(tmp64);

	pll_ref /= 1000;

	/* 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;
	}

	if (nint > 63) {
		tuner_info("No valid PLL values for %u kHz!\n", freq);
		return -EINVAL;
	}

	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;
	}

	rc = r820t_write_reg_mask(priv, 0x16, sdm >> 8, 0x08);
	if (rc < 0)
		return rc;
	rc = r820t_write_reg_mask(priv, 0x15, sdm & 0xff, 0x08);
	if (rc < 0)
		return rc;

	for (i = 0; i < 2; i++) {
		/*
		 * FIXME: Rafael chips R620D, R828D and R828 seems to
		 * need 20 ms for analog TV
		 */
		msleep(10);

		/* Check if PLL has locked */
		rc = r820_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;
	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;
	}

	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 = 0x00;	/* r15[7]: flt_ext_wide off */
		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_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 */
#if 0 /* 7 MHz type 2 - nor sure why/where this is used - Perhaps Australia? */
			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 */
#endif
		} 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;
		msleep(1);
	}
	priv->int_freq = if_khz;

	/* 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, filt_cal_lo);
			if (rc < 0 || !priv->has_lock)
				return rc;

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

			msleep(1);

			/* 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 = r820_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, 0x10);
	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 = r820_read(priv, 0x00, data, sizeof(data));
	if (rc < 0)
		return rc;

	return ((data[3] & 0x0f) << 1) + ((data[3] & 0xf0) >> 4);
}

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 = -EINVAL;
	u32				lo_freq;

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

	mutex_lock(&priv->lock);

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

	rc = r820t_set_mux(priv, lo_freq);
	if (rc < 0)
		goto err;
	rc = r820t_set_pll(priv, lo_freq);
	if (rc < 0 || !priv->has_lock)
		goto err;

	rc = r820t_sysfreq_sel(priv, freq, type, std, delsys);
err:
	mutex_unlock(&priv->lock);

	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;

	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;

		msleep(5);

		rc = r820_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];
}

/*
 *  r820t frontend operations and tuner attach code
 */

static int r820t_init(struct dvb_frontend *fe)
{
	struct r820t_priv *priv = fe->tuner_priv;
	int rc, i;
	int xtal_cap = 0;

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

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

	mutex_lock(&priv->lock);

	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 {
		for (i = 0; i < 3; i++) {
			rc = r820t_xtal_check(priv);
			if (rc < 0)
				goto err;
			if (!i || rc > xtal_cap)
				xtal_cap = rc;
		}
		priv->xtal_cap_sel = xtal_cap;
	}

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

	mutex_unlock(&priv->lock);

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

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

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

	mutex_lock(&priv->lock);
	rc = r820t_standby(priv);
	mutex_unlock(&priv->lock);

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

	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;

	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;

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

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);

	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);

	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;

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

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

	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 int 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;

	kfree(fe->tuner_priv);

	return 0;
}

static const struct dvb_tuner_ops r820t_tuner_ops = {
	.info = {
		.name           = "Rafael Micro R820T",
		.frequency_min  =   42000000,
		.frequency_max  = 1002000000,
	},
	.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;
		break;
	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;
	}

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

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

	/* check if the tuner is there */
	rc = r820_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");

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

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

	mutex_unlock(&r820t_list_mutex);

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

err_no_gate:
	mutex_unlock(&r820t_list_mutex);

	tuner_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 <mchehab@redhat.com>");
MODULE_LICENSE("GPL");