/*
Driver for Samsung S5H1420 QPSK Demodulator

Copyright (C) 2005 Andrew de Quincey <adq_dvb@lidskialf.net>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

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

#include "dvb_frontend.h"
#include "s5h1420.h"



#define TONE_FREQ 22000

struct s5h1420_state {
	struct i2c_adapter* i2c;
	struct dvb_frontend_ops ops;
	const struct s5h1420_config* config;
	struct dvb_frontend frontend;

	u8 postlocked:1;
	u32 fclk;
	u32 tunedfreq;
	fe_code_rate_t fec_inner;
	u32 symbol_rate;
};

static u32 s5h1420_getsymbolrate(struct s5h1420_state* state);
static int s5h1420_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings);


static int debug = 0;
#define dprintk if (debug) printk

static int s5h1420_writereg (struct s5h1420_state* state, u8 reg, u8 data)
{
	u8 buf [] = { reg, data };
	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, .len = 2 };
	int err;

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

	return 0;
}

static u8 s5h1420_readreg (struct s5h1420_state* state, u8 reg)
{
	int ret;
	u8 b0 [] = { reg };
	u8 b1 [] = { 0 };
	struct i2c_msg msg1 = { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 1 };
	struct i2c_msg msg2 = { .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 1 };

	if ((ret = i2c_transfer (state->i2c, &msg1, 1)) != 1)
		return ret;

	if ((ret = i2c_transfer (state->i2c, &msg2, 1)) != 1)
		return ret;

	return b1[0];
}

static int s5h1420_set_voltage (struct dvb_frontend* fe, fe_sec_voltage_t voltage)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	switch(voltage) {
	case SEC_VOLTAGE_13:
		s5h1420_writereg(state, 0x3c, (s5h1420_readreg(state, 0x3c) & 0xfe) | 0x02);
		break;

	case SEC_VOLTAGE_18:
		s5h1420_writereg(state, 0x3c, s5h1420_readreg(state, 0x3c) | 0x03);
		break;

	case SEC_VOLTAGE_OFF:
		s5h1420_writereg(state, 0x3c, s5h1420_readreg(state, 0x3c) & 0xfd);
		break;
	}

	return 0;
}

static int s5h1420_set_tone (struct dvb_frontend* fe, fe_sec_tone_mode_t tone)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	switch(tone) {
	case SEC_TONE_ON:
		s5h1420_writereg(state, 0x3b, (s5h1420_readreg(state, 0x3b) & 0x74) | 0x08);
		break;

	case SEC_TONE_OFF:
		s5h1420_writereg(state, 0x3b, (s5h1420_readreg(state, 0x3b) & 0x74) | 0x01);
		break;
	}

	return 0;
}

static int s5h1420_send_master_cmd (struct dvb_frontend* fe, struct dvb_diseqc_master_cmd* cmd)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	u8 val;
	int i;
	unsigned long timeout;
	int result = 0;

	/* setup for DISEQC */
	val = s5h1420_readreg(state, 0x3b);
	s5h1420_writereg(state, 0x3b, 0x02);
	msleep(15);

	/* write the DISEQC command bytes */
	for(i=0; i< cmd->msg_len; i++) {
		s5h1420_writereg(state, 0x3c + i, cmd->msg[i]);
	}

	/* kick off transmission */
	s5h1420_writereg(state, 0x3b, s5h1420_readreg(state, 0x3b) | ((cmd->msg_len-1) << 4) | 0x08);

	/* wait for transmission to complete */
	timeout = jiffies + ((100*HZ) / 1000);
	while(time_before(jiffies, timeout)) {
		if (s5h1420_readreg(state, 0x3b) & 0x08)
			break;

		msleep(5);
	}
	if (time_after(jiffies, timeout))
		result = -ETIMEDOUT;

	/* restore original settings */
	s5h1420_writereg(state, 0x3b, val);
	msleep(15);
	return result;
}

static int s5h1420_recv_slave_reply (struct dvb_frontend* fe, struct dvb_diseqc_slave_reply* reply)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	u8 val;
	int i;
	int length;
	unsigned long timeout;
	int result = 0;

	/* setup for DISEQC recieve */
	val = s5h1420_readreg(state, 0x3b);
	s5h1420_writereg(state, 0x3b, 0x82); /* FIXME: guess - do we need to set DIS_RDY(0x08) in receive mode? */
	msleep(15);

	/* wait for reception to complete */
	timeout = jiffies + ((reply->timeout*HZ) / 1000);
	while(time_before(jiffies, timeout)) {
		if (!(s5h1420_readreg(state, 0x3b) & 0x80)) /* FIXME: do we test DIS_RDY(0x08) or RCV_EN(0x80)? */
			break;

		msleep(5);
	}
	if (time_after(jiffies, timeout)) {
		result = -ETIMEDOUT;
		goto exit;
	}

	/* check error flag - FIXME: not sure what this does - docs do not describe
	 * beyond "error flag for diseqc receive data :( */
	if (s5h1420_readreg(state, 0x49)) {
		result = -EIO;
		goto exit;
	}

	/* check length */
	length = (s5h1420_readreg(state, 0x3b) & 0x70) >> 4;
	if (length > sizeof(reply->msg)) {
		result = -EOVERFLOW;
		goto exit;
	}
	reply->msg_len = length;

	/* extract data */
	for(i=0; i< length; i++) {
		reply->msg[i] = s5h1420_readreg(state, 0x3c + i);
	}

exit:
	/* restore original settings */
	s5h1420_writereg(state, 0x3b, val);
	msleep(15);
	return result;
}

static int s5h1420_send_burst (struct dvb_frontend* fe, fe_sec_mini_cmd_t minicmd)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	u8 val;
	int result = 0;
	unsigned long timeout;

	/* setup for tone burst */
	val = s5h1420_readreg(state, 0x3b);
	s5h1420_writereg(state, 0x3b, (s5h1420_readreg(state, 0x3b) & 0x70) | 0x01);

	/* set value for B position if requested */
	if (minicmd == SEC_MINI_B) {
		s5h1420_writereg(state, 0x3b, s5h1420_readreg(state, 0x3b) | 0x04);
	}
	msleep(15);

	/* start transmission */
	s5h1420_writereg(state, 0x3b, s5h1420_readreg(state, 0x3b) | 0x08);

	/* wait for transmission to complete */
	timeout = jiffies + ((20*HZ) / 1000);
	while(time_before(jiffies, timeout)) {
		if (!(s5h1420_readreg(state, 0x3b) & 0x08))
			break;

		msleep(5);
	}
	if (time_after(jiffies, timeout))
		result = -ETIMEDOUT;

	/* restore original settings */
	s5h1420_writereg(state, 0x3b, val);
	msleep(15);
	return result;
}

static fe_status_t s5h1420_get_status_bits(struct s5h1420_state* state)
{
	u8 val;
	fe_status_t status = 0;

	val = s5h1420_readreg(state, 0x14);
	if (val & 0x02)
		status |=  FE_HAS_SIGNAL; // FIXME: not sure if this is right
	if (val & 0x01)
		status |=  FE_HAS_CARRIER; // FIXME: not sure if this is right
	val = s5h1420_readreg(state, 0x36);
	if (val & 0x01)
		status |=  FE_HAS_VITERBI;
	if (val & 0x20)
		status |=  FE_HAS_SYNC;
	if (status == (FE_HAS_SIGNAL|FE_HAS_CARRIER|FE_HAS_VITERBI|FE_HAS_SYNC))
		status |=  FE_HAS_LOCK;

	return status;
}

static int s5h1420_read_status(struct dvb_frontend* fe, fe_status_t* status)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	u8 val;

	if (status == NULL)
		return -EINVAL;

	/* determine lock state */
	*status = s5h1420_get_status_bits(state);

	/* fix for FEC 5/6 inversion issue - if it doesn't quite lock, invert the inversion,
	wait a bit and check again */
	if (*status == (FE_HAS_SIGNAL|FE_HAS_CARRIER|FE_HAS_VITERBI)) {
		val = s5h1420_readreg(state, 0x32);
		if ((val & 0x07) == 0x03) {
			if (val & 0x08)
				s5h1420_writereg(state, 0x31, 0x13);
			else
				s5h1420_writereg(state, 0x31, 0x1b);

			/* wait a bit then update lock status */
			mdelay(200);
			*status = s5h1420_get_status_bits(state);
		}
	}

	/* perform post lock setup */
	if ((*status & FE_HAS_LOCK) && (!state->postlocked)) {

		/* calculate the data rate */
		u32 tmp = s5h1420_getsymbolrate(state);
		switch(s5h1420_readreg(state, 0x32) & 0x07) {
		case 0:
			tmp = (tmp * 2 * 1) / 2;
			break;

		case 1:
			tmp = (tmp * 2 * 2) / 3;
			break;

		case 2:
			tmp = (tmp * 2 * 3) / 4;
			break;

		case 3:
			tmp = (tmp * 2 * 5) / 6;
			break;

		case 4:
			tmp = (tmp * 2 * 6) / 7;
			break;

		case 5:
			tmp = (tmp * 2 * 7) / 8;
			break;
		}
		tmp = state->fclk / tmp;

		/* set the MPEG_CLK_INTL for the calculated data rate */
		if (tmp < 4)
			val = 0x00;
		else if (tmp < 8)
			val = 0x01;
		else if (tmp < 12)
			val = 0x02;
		else if (tmp < 16)
			val = 0x03;
		else if (tmp < 24)
			val = 0x04;
		else if (tmp < 32)
			val = 0x05;
		else
			val = 0x06;
		s5h1420_writereg(state, 0x22, val);

		/* DC freeze */
		s5h1420_writereg(state, 0x1f, s5h1420_readreg(state, 0x1f) | 0x01);

		/* kicker disable + remove DC offset */
		s5h1420_writereg(state, 0x05, s5h1420_readreg(state, 0x05) & 0x6f);

		/* post-lock processing has been done! */
		state->postlocked = 1;
	}

	return 0;
}

static int s5h1420_read_ber(struct dvb_frontend* fe, u32* ber)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	s5h1420_writereg(state, 0x46, 0x1d);
	mdelay(25);
	return (s5h1420_readreg(state, 0x48) << 8) | s5h1420_readreg(state, 0x47);
}

static int s5h1420_read_signal_strength(struct dvb_frontend* fe, u16* strength)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	u8 val = 0xff - s5h1420_readreg(state, 0x15);

	return (int) ((val << 8) | val);
}

static int s5h1420_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	s5h1420_writereg(state, 0x46, 0x1f);
	mdelay(25);
	return (s5h1420_readreg(state, 0x48) << 8) | s5h1420_readreg(state, 0x47);
}

static void s5h1420_reset(struct s5h1420_state* state)
{
	s5h1420_writereg (state, 0x01, 0x08);
	s5h1420_writereg (state, 0x01, 0x00);
	udelay(10);
}

static void s5h1420_setsymbolrate(struct s5h1420_state* state, struct dvb_frontend_parameters *p)
{
	u64 val;

	val = (p->u.qpsk.symbol_rate / 1000) * (1<<24);
	if (p->u.qpsk.symbol_rate <= 21000000) {
		val *= 2;
	}
	do_div(val, (state->fclk / 1000));

	s5h1420_writereg(state, 0x09, s5h1420_readreg(state, 0x09) & 0x7f);
	s5h1420_writereg(state, 0x11, val >> 16);
	s5h1420_writereg(state, 0x12, val >> 8);
	s5h1420_writereg(state, 0x13, val & 0xff);
	s5h1420_writereg(state, 0x09, s5h1420_readreg(state, 0x09) | 0x80);
}

static u32 s5h1420_getsymbolrate(struct s5h1420_state* state)
{
	u64 val;
	int sampling = 2;

	if (s5h1420_readreg(state, 0x05) & 0x2)
		sampling = 1;

	s5h1420_writereg(state, 0x06, s5h1420_readreg(state, 0x06) | 0x08);
	val  = s5h1420_readreg(state, 0x11) << 16;
	val |= s5h1420_readreg(state, 0x12) << 8;
	val |= s5h1420_readreg(state, 0x13);
	s5h1420_writereg(state, 0x06, s5h1420_readreg(state, 0x06) & 0xf7);

	val *= (state->fclk / 1000);
	do_div(val, ((1<<24) * sampling));

	return (u32) (val * 1000);
}

static void s5h1420_setfreqoffset(struct s5h1420_state* state, int freqoffset)
{
	int val;

	/* remember freqoffset is in kHz, but the chip wants the offset in Hz, so
	 * divide fclk by 1000000 to get the correct value. */
	val = -(int) ((freqoffset * (1<<24)) / (state->fclk / 1000000));

	s5h1420_writereg(state, 0x09, s5h1420_readreg(state, 0x09) & 0xbf);
	s5h1420_writereg(state, 0x0e, val >> 16);
	s5h1420_writereg(state, 0x0f, val >> 8);
	s5h1420_writereg(state, 0x10, val & 0xff);
	s5h1420_writereg(state, 0x09, s5h1420_readreg(state, 0x09) | 0x40);
}

static int s5h1420_getfreqoffset(struct s5h1420_state* state)
{
	int val;

	s5h1420_writereg(state, 0x06, s5h1420_readreg(state, 0x06) | 0x08);
	val  = s5h1420_readreg(state, 0x0e) << 16;
	val |= s5h1420_readreg(state, 0x0f) << 8;
	val |= s5h1420_readreg(state, 0x10);
	s5h1420_writereg(state, 0x06, s5h1420_readreg(state, 0x06) & 0xf7);

	if (val & 0x800000)
		val |= 0xff000000;

	/* remember freqoffset is in kHz, but the chip wants the offset in Hz, so
	 * divide fclk by 1000000 to get the correct value. */
	val = - ((val * (state->fclk/1000000)) / (1<<24));

	return val;
}

static void s5h1420_setfec(struct s5h1420_state* state, struct dvb_frontend_parameters *p)
{
	if ((p->u.qpsk.fec_inner == FEC_AUTO) || (p->inversion == INVERSION_AUTO)) {
		s5h1420_writereg(state, 0x31, 0x00);
		s5h1420_writereg(state, 0x30, 0x3f);
	} else {
		switch(p->u.qpsk.fec_inner) {
		case FEC_1_2:
			s5h1420_writereg(state, 0x31, 0x10);
			s5h1420_writereg(state, 0x30, 0x01);
			break;

		case FEC_2_3:
			s5h1420_writereg(state, 0x31, 0x11);
			s5h1420_writereg(state, 0x30, 0x02);
			break;

		case FEC_3_4:
			s5h1420_writereg(state, 0x31, 0x12);
			s5h1420_writereg(state, 0x30, 0x04);
			break;

		case FEC_5_6:
			s5h1420_writereg(state, 0x31, 0x13);
			s5h1420_writereg(state, 0x30, 0x08);
			break;

		case FEC_6_7:
			s5h1420_writereg(state, 0x31, 0x14);
			s5h1420_writereg(state, 0x30, 0x10);
			break;

		case FEC_7_8:
			s5h1420_writereg(state, 0x31, 0x15);
			s5h1420_writereg(state, 0x30, 0x20);
			break;

		default:
			return;
		}
	}
}

static fe_code_rate_t s5h1420_getfec(struct s5h1420_state* state)
{
	switch(s5h1420_readreg(state, 0x32) & 0x07) {
	case 0:
		return FEC_1_2;

	case 1:
		return FEC_2_3;

	case 2:
		return FEC_3_4;

	case 3:
		return FEC_5_6;

	case 4:
		return FEC_6_7;

	case 5:
		return FEC_7_8;
	}

	return FEC_NONE;
}

static void s5h1420_setinversion(struct s5h1420_state* state, struct dvb_frontend_parameters *p)
{
	if ((p->u.qpsk.fec_inner == FEC_AUTO) || (p->inversion == INVERSION_AUTO)) {
		s5h1420_writereg(state, 0x31, 0x00);
		s5h1420_writereg(state, 0x30, 0x3f);
	} else {
		u8 tmp = s5h1420_readreg(state, 0x31) & 0xf7;
			tmp |= 0x10;

		if (p->inversion == INVERSION_ON)
			tmp |= 0x80;

		s5h1420_writereg(state, 0x31, tmp);
	}
}

static fe_spectral_inversion_t s5h1420_getinversion(struct s5h1420_state* state)
{
	if (s5h1420_readreg(state, 0x32) & 0x08)
		return INVERSION_ON;

	return INVERSION_OFF;
}

static int s5h1420_set_frontend(struct dvb_frontend* fe, struct dvb_frontend_parameters *p)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	u32 frequency_delta;
	struct dvb_frontend_tune_settings fesettings;

	/* check if we should do a fast-tune */
	memcpy(&fesettings.parameters, p, sizeof(struct dvb_frontend_parameters));
	s5h1420_get_tune_settings(fe, &fesettings);
	frequency_delta = p->frequency - state->tunedfreq;
	if ((frequency_delta > -fesettings.max_drift) && (frequency_delta < fesettings.max_drift) &&
	    (frequency_delta != 0) &&
	    (state->fec_inner == p->u.qpsk.fec_inner) &&
	    (state->symbol_rate == p->u.qpsk.symbol_rate)) {

		s5h1420_setfreqoffset(state, frequency_delta);
		return 0;
	}

	/* first of all, software reset */
	s5h1420_reset(state);

	/* set tuner PLL */
	if (state->config->pll_set) {
		s5h1420_writereg (state, 0x02, s5h1420_readreg(state,0x02) | 1);
		state->config->pll_set(fe, p, &state->tunedfreq);
		s5h1420_writereg (state, 0x02, s5h1420_readreg(state,0x02) & 0xfe);
	}

	/* set s5h1420 fclk PLL according to desired symbol rate */
	if (p->u.qpsk.symbol_rate > 28000000) {
		state->fclk = 88000000;
		s5h1420_writereg(state, 0x03, 0x50);
		s5h1420_writereg(state, 0x04, 0x40);
		s5h1420_writereg(state, 0x05, 0xae);
	} else if (p->u.qpsk.symbol_rate > 21000000) {
		state->fclk = 59000000;
		s5h1420_writereg(state, 0x03, 0x33);
		s5h1420_writereg(state, 0x04, 0x40);
		s5h1420_writereg(state, 0x05, 0xae);
	} else {
		state->fclk = 88000000;
		s5h1420_writereg(state, 0x03, 0x50);
		s5h1420_writereg(state, 0x04, 0x40);
		s5h1420_writereg(state, 0x05, 0xac);
	}

	/* set misc registers */
	s5h1420_writereg(state, 0x02, 0x00);
	s5h1420_writereg(state, 0x07, 0xb0);
	s5h1420_writereg(state, 0x0a, 0x67);
	s5h1420_writereg(state, 0x0b, 0x78);
	s5h1420_writereg(state, 0x0c, 0x48);
	s5h1420_writereg(state, 0x0d, 0x6b);
	s5h1420_writereg(state, 0x2e, 0x8e);
	s5h1420_writereg(state, 0x35, 0x33);
	s5h1420_writereg(state, 0x38, 0x01);
	s5h1420_writereg(state, 0x39, 0x7d);
	s5h1420_writereg(state, 0x3a, (state->fclk + (TONE_FREQ * 32) - 1) / (TONE_FREQ * 32));
	s5h1420_writereg(state, 0x3c, 0x00);
	s5h1420_writereg(state, 0x45, 0x61);
	s5h1420_writereg(state, 0x46, 0x1d);

	/* start QPSK */
	s5h1420_writereg(state, 0x05, s5h1420_readreg(state, 0x05) | 1);

	/* set the frequency offset to adjust for PLL inaccuracy */
	s5h1420_setfreqoffset(state, p->frequency - state->tunedfreq);

	/* set the reset of the parameters */
	s5h1420_setsymbolrate(state, p);
	s5h1420_setinversion(state, p);
	s5h1420_setfec(state, p);

	state->fec_inner = p->u.qpsk.fec_inner;
	state->symbol_rate = p->u.qpsk.symbol_rate;
	state->postlocked = 0;
	return 0;
}

static int s5h1420_get_frontend(struct dvb_frontend* fe, struct dvb_frontend_parameters *p)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	p->frequency = state->tunedfreq + s5h1420_getfreqoffset(state);
	p->inversion = s5h1420_getinversion(state);
	p->u.qpsk.symbol_rate = s5h1420_getsymbolrate(state);
	p->u.qpsk.fec_inner = s5h1420_getfec(state);

	return 0;
}

static int s5h1420_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings)
{
	if (fesettings->parameters.u.qpsk.symbol_rate > 20000000) {
		fesettings->min_delay_ms = 50;
		fesettings->step_size = 2000;
		fesettings->max_drift = 8000;
	} else if (fesettings->parameters.u.qpsk.symbol_rate > 12000000) {
		fesettings->min_delay_ms = 100;
		fesettings->step_size = 1500;
		fesettings->max_drift = 9000;
	} else if (fesettings->parameters.u.qpsk.symbol_rate > 8000000) {
		fesettings->min_delay_ms = 100;
		fesettings->step_size = 1000;
		fesettings->max_drift = 8000;
	} else if (fesettings->parameters.u.qpsk.symbol_rate > 4000000) {
		fesettings->min_delay_ms = 100;
		fesettings->step_size = 500;
		fesettings->max_drift = 7000;
	} else if (fesettings->parameters.u.qpsk.symbol_rate > 2000000) {
		fesettings->min_delay_ms = 200;
		fesettings->step_size = (fesettings->parameters.u.qpsk.symbol_rate / 8000);
		fesettings->max_drift = 14 * fesettings->step_size;
	} else {
		fesettings->min_delay_ms = 200;
		fesettings->step_size = (fesettings->parameters.u.qpsk.symbol_rate / 8000);
		fesettings->max_drift = 18 * fesettings->step_size;
	}

	return 0;
}

static int s5h1420_init (struct dvb_frontend* fe)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	/* disable power down and do reset */
	s5h1420_writereg(state, 0x02, 0x10);
	msleep(10);
	s5h1420_reset(state);

	/* init PLL */
	if (state->config->pll_init) {
		s5h1420_writereg (state, 0x02, s5h1420_readreg(state,0x02) | 1);
		state->config->pll_init(fe);
		s5h1420_writereg (state, 0x02, s5h1420_readreg(state,0x02) & 0xfe);
	}

	return 0;
}

static int s5h1420_sleep(struct dvb_frontend* fe)
{
	struct s5h1420_state* state = fe->demodulator_priv;

	return s5h1420_writereg(state, 0x02, 0x12);
}

static void s5h1420_release(struct dvb_frontend* fe)
{
	struct s5h1420_state* state = fe->demodulator_priv;
	kfree(state);
}

static struct dvb_frontend_ops s5h1420_ops;

struct dvb_frontend* s5h1420_attach(const struct s5h1420_config* config, struct i2c_adapter* i2c)
{
	struct s5h1420_state* state = NULL;
	u8 identity;

	/* allocate memory for the internal state */
	state = kmalloc(sizeof(struct s5h1420_state), GFP_KERNEL);
	if (state == NULL)
		goto error;

	/* setup the state */
	state->config = config;
	state->i2c = i2c;
	memcpy(&state->ops, &s5h1420_ops, sizeof(struct dvb_frontend_ops));
	state->postlocked = 0;
	state->fclk = 88000000;
	state->tunedfreq = 0;
	state->fec_inner = FEC_NONE;
	state->symbol_rate = 0;

	/* check if the demod is there + identify it */
	identity = s5h1420_readreg(state, 0x00);
	if (identity != 0x03)
		goto error;

	/* create dvb_frontend */
	state->frontend.ops = &state->ops;
	state->frontend.demodulator_priv = state;
	return &state->frontend;

error:
	kfree(state);
	return NULL;
}

static struct dvb_frontend_ops s5h1420_ops = {

	.info = {
		.name     = "Samsung S5H1420 DVB-S",
		.type     = FE_QPSK,
		.frequency_min    = 950000,
		.frequency_max    = 2150000,
		.frequency_stepsize = 125,     /* kHz for QPSK frontends */
		.frequency_tolerance  = 29500,
		.symbol_rate_min  = 1000000,
		.symbol_rate_max  = 45000000,
		/*  .symbol_rate_tolerance  = ???,*/
		.caps = FE_CAN_INVERSION_AUTO |
		FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
		FE_CAN_FEC_5_6 | FE_CAN_FEC_6_7 | FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
		FE_CAN_QPSK
	},

	.release = s5h1420_release,

	.init = s5h1420_init,
	.sleep = s5h1420_sleep,

	.set_frontend = s5h1420_set_frontend,
	.get_frontend = s5h1420_get_frontend,
	.get_tune_settings = s5h1420_get_tune_settings,

	.read_status = s5h1420_read_status,
	.read_ber = s5h1420_read_ber,
	.read_signal_strength = s5h1420_read_signal_strength,
	.read_ucblocks = s5h1420_read_ucblocks,

	.diseqc_send_master_cmd = s5h1420_send_master_cmd,
	.diseqc_recv_slave_reply = s5h1420_recv_slave_reply,
	.diseqc_send_burst = s5h1420_send_burst,
	.set_tone = s5h1420_set_tone,
	.set_voltage = s5h1420_set_voltage,
};

module_param(debug, int, 0644);

MODULE_DESCRIPTION("Samsung S5H1420 DVB-S Demodulator driver");
MODULE_AUTHOR("Andrew de Quincey");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(s5h1420_attach);