drivers/media/usb/dvb-usb/friio-fe.c - arm/linux - Git at Google

 /* DVB USB compliant Linux driver for the Friio USB2.0 ISDB-T receiver.
  *
  * Copyright (C) 2009 Akihiro Tsukada <tskd2@yahoo.co.jp>
  *
  * This module is based off the the gl861 and vp702x modules.
  *
  * 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, version 2.
  *
  * see Documentation/dvb/README.dvb-usb for more information
  */
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/slab.h>

 #include "friio.h"

 struct jdvbt90502_state {
 	struct i2c_adapter *i2c;
 	struct dvb_frontend frontend;
 	struct jdvbt90502_config config;
 };

 /* NOTE: TC90502 has 16bit register-address? */
 /* register 0x0100 is used for reading PLL status, so reg is u16 here */
 static int jdvbt90502_reg_read(struct jdvbt90502_state *state,
 			       const u16 reg, u8 *buf, const size_t count)
 {
 	int ret;
 	u8 wbuf[3];
 	struct i2c_msg msg[2];

 	wbuf[0] = reg & 0xFF;
 	wbuf[1] = 0;
 	wbuf[2] = reg >> 8;

 	msg[0].addr = state->config.demod_address;
 	msg[0].flags = 0;
 	msg[0].buf = wbuf;
 	msg[0].len = sizeof(wbuf);

 	msg[1].addr = msg[0].addr;
 	msg[1].flags = I2C_M_RD;
 	msg[1].buf = buf;
 	msg[1].len = count;

 	ret = i2c_transfer(state->i2c, msg, 2);
 	if (ret != 2) {
 		deb_fe(" reg read failed.\n");
 		return -EREMOTEIO;
 	}
 	return 0;
 }

 /* currently 16bit register-address is not used, so reg is u8 here */
 static int jdvbt90502_single_reg_write(struct jdvbt90502_state *state,
 				       const u8 reg, const u8 val)
 {
 	struct i2c_msg msg;
 	u8 wbuf[2];

 	wbuf[0] = reg;
 	wbuf[1] = val;

 	msg.addr = state->config.demod_address;
 	msg.flags = 0;
 	msg.buf = wbuf;
 	msg.len = sizeof(wbuf);

 	if (i2c_transfer(state->i2c, &msg, 1) != 1) {
 		deb_fe(" reg write failed.");
 		return -EREMOTEIO;
 	}
 	return 0;
 }

 static int _jdvbt90502_write(struct dvb_frontend *fe, const u8 buf[], int len)
 {
 	struct jdvbt90502_state *state = fe->demodulator_priv;
 	int err, i;
 	for (i = 0; i < len - 1; i++) {
 		err = jdvbt90502_single_reg_write(state,
 						  buf[0] + i, buf[i + 1]);
 		if (err)
 			return err;
 	}

 	return 0;
 }

 /* read pll status byte via the demodulator's I2C register */
 /* note: Win box reads it by 8B block at the I2C addr 0x30 from reg:0x80 */
 static int jdvbt90502_pll_read(struct jdvbt90502_state *state, u8 *result)
 {
 	int ret;

 	/* +1 for reading */
 	u8 pll_addr_byte = (state->config.pll_address << 1) + 1;

 	*result = 0;

 	ret = jdvbt90502_single_reg_write(state, JDVBT90502_2ND_I2C_REG,
 					  pll_addr_byte);
 	if (ret)
 		goto error;

 	ret = jdvbt90502_reg_read(state, 0x0100, result, 1);
 	if (ret)
 		goto error;

 	deb_fe("PLL read val:%02x\n", *result);
 	return 0;

 error:
 	deb_fe("%s:ret == %d\n", __func__, ret);
 	return -EREMOTEIO;
 }


 /* set pll frequency via the demodulator's I2C register */
 static int jdvbt90502_pll_set_freq(struct jdvbt90502_state *state, u32 freq)
 {
 	int ret;
 	int retry;
 	u8 res1;
 	u8 res2[9];

 	u8 pll_freq_cmd[PLL_CMD_LEN];
 	u8 pll_agc_cmd[PLL_CMD_LEN];
 	struct i2c_msg msg[2];
 	u32 f;

 	deb_fe("%s: freq=%d, step=%d\n", __func__, freq,
 	       state->frontend.ops.info.frequency_stepsize);
 	/* freq -> oscilator frequency conversion. */
 	/* freq: 473,000,000 + n*6,000,000 [+ 142857 (center freq. shift)] */
 	f = freq / state->frontend.ops.info.frequency_stepsize;
 	/* add 399[1/7 MHZ] = 57MHz for the IF  */
 	f += 399;
 	/* add center frequency shift if necessary */
 	if (f % 7 == 0)
 		f++;
 	pll_freq_cmd[DEMOD_REDIRECT_REG] = JDVBT90502_2ND_I2C_REG; /* 0xFE */
 	pll_freq_cmd[ADDRESS_BYTE] = state->config.pll_address << 1;
 	pll_freq_cmd[DIVIDER_BYTE1] = (f >> 8) & 0x7F;
 	pll_freq_cmd[DIVIDER_BYTE2] = f & 0xFF;
 	pll_freq_cmd[CONTROL_BYTE] = 0xB2; /* ref.divider:28, 4MHz/28=1/7MHz */
 	pll_freq_cmd[BANDSWITCH_BYTE] = 0x08;	/* UHF band */

 	msg[0].addr = state->config.demod_address;
 	msg[0].flags = 0;
 	msg[0].buf = pll_freq_cmd;
 	msg[0].len = sizeof(pll_freq_cmd);

 	ret = i2c_transfer(state->i2c, &msg[0], 1);
 	if (ret != 1)
 		goto error;

 	udelay(50);

 	pll_agc_cmd[DEMOD_REDIRECT_REG] = pll_freq_cmd[DEMOD_REDIRECT_REG];
 	pll_agc_cmd[ADDRESS_BYTE] = pll_freq_cmd[ADDRESS_BYTE];
 	pll_agc_cmd[DIVIDER_BYTE1] = pll_freq_cmd[DIVIDER_BYTE1];
 	pll_agc_cmd[DIVIDER_BYTE2] = pll_freq_cmd[DIVIDER_BYTE2];
 	pll_agc_cmd[CONTROL_BYTE] = 0x9A; /*  AGC_CTRL instead of BANDSWITCH */
 	pll_agc_cmd[AGC_CTRL_BYTE] = 0x50;
 	/* AGC Time Constant 2s, AGC take-over point:103dBuV(lowest) */

 	msg[1].addr = msg[0].addr;
 	msg[1].flags = 0;
 	msg[1].buf = pll_agc_cmd;
 	msg[1].len = sizeof(pll_agc_cmd);

 	ret = i2c_transfer(state->i2c, &msg[1], 1);
 	if (ret != 1)
 		goto error;

 	/* I don't know what these cmds are for,  */
 	/* but the USB log on a windows box contains them */
 	ret = jdvbt90502_single_reg_write(state, 0x01, 0x40);
 	ret |= jdvbt90502_single_reg_write(state, 0x01, 0x00);
 	if (ret)
 		goto error;
 	udelay(100);

 	/* wait for the demod to be ready? */
 #define RETRY_COUNT 5
 	for (retry = 0; retry < RETRY_COUNT; retry++) {
 		ret = jdvbt90502_reg_read(state, 0x0096, &res1, 1);
 		if (ret)
 			goto error;
 		/* if (res1 != 0x00) goto error; */
 		ret = jdvbt90502_reg_read(state, 0x00B0, res2, sizeof(res2));
 		if (ret)
 			goto error;
 		if (res2[0] >= 0xA7)
 			break;
 		msleep(100);
 	}
 	if (retry >= RETRY_COUNT) {
 		deb_fe("%s: FE does not get ready after freq setting.\n",
 		       __func__);
 		return -EREMOTEIO;
 	}

 	return 0;
 error:
 	deb_fe("%s:ret == %d\n", __func__, ret);
 	return -EREMOTEIO;
 }

 static int jdvbt90502_read_status(struct dvb_frontend *fe,
 				  enum fe_status *state)
 {
 	u8 result;
 	int ret;

 	*state = FE_HAS_SIGNAL;

 	ret = jdvbt90502_pll_read(fe->demodulator_priv, &result);
 	if (ret) {
 		deb_fe("%s:ret == %d\n", __func__, ret);
 		return -EREMOTEIO;
 	}

 	*state = FE_HAS_SIGNAL
 		| FE_HAS_CARRIER
 		| FE_HAS_VITERBI
 		| FE_HAS_SYNC;

 	if (result & PLL_STATUS_LOCKED)
 		*state |= FE_HAS_LOCK;

 	return 0;
 }

 static int jdvbt90502_read_signal_strength(struct dvb_frontend *fe,
 					   u16 *strength)
 {
 	int ret;
 	u8 rbuf[37];

 	*strength = 0;

 	/* status register (incl. signal strength) : 0x89  */
 	/* TODO: read just the necessary registers [0x8B..0x8D]? */
 	ret = jdvbt90502_reg_read(fe->demodulator_priv, 0x0089,
 				  rbuf, sizeof(rbuf));

 	if (ret) {
 		deb_fe("%s:ret == %d\n", __func__, ret);
 		return -EREMOTEIO;
 	}

 	/* signal_strength: rbuf[2-4] (24bit BE), use lower 16bit for now. */
 	*strength = (rbuf[3] << 8) + rbuf[4];
 	if (rbuf[2])
 		*strength = 0xffff;

 	return 0;
 }


 /* filter out un-supported properties to notify users */
 static int jdvbt90502_set_property(struct dvb_frontend *fe,
 				   struct dtv_property *tvp)
 {
 	int r = 0;

 	switch (tvp->cmd) {
 	case DTV_DELIVERY_SYSTEM:
 		if (tvp->u.data != SYS_ISDBT)
 			r = -EINVAL;
 		break;
 	case DTV_CLEAR:
 	case DTV_TUNE:
 	case DTV_FREQUENCY:
 		break;
 	default:
 		r = -EINVAL;
 	}
 	return r;
 }

 static int jdvbt90502_set_frontend(struct dvb_frontend *fe)
 {
 	struct dtv_frontend_properties *p = &fe->dtv_property_cache;

 	/**
 	 * NOTE: ignore all the parameters except frequency.
 	 *       others should be fixed to the proper value for ISDB-T,
 	 *       but don't check here.
 	 */

 	struct jdvbt90502_state *state = fe->demodulator_priv;
 	int ret;

 	deb_fe("%s: Freq:%d\n", __func__, p->frequency);

 	/* This driver only works on auto mode */
 	p->inversion = INVERSION_AUTO;
 	p->bandwidth_hz = 6000000;
 	p->code_rate_HP = FEC_AUTO;
 	p->code_rate_LP = FEC_AUTO;
 	p->modulation = QAM_64;
 	p->transmission_mode = TRANSMISSION_MODE_AUTO;
 	p->guard_interval = GUARD_INTERVAL_AUTO;
 	p->hierarchy = HIERARCHY_AUTO;
 	p->delivery_system = SYS_ISDBT;

 	ret = jdvbt90502_pll_set_freq(state, p->frequency);
 	if (ret) {
 		deb_fe("%s:ret == %d\n", __func__, ret);
 		return -EREMOTEIO;
 	}

 	return 0;
 }


 /**
  * (reg, val) commad list to initialize this module.
  *  captured on a Windows box.
  */
 static u8 init_code[][2] = {
 	{0x01, 0x40},
 	{0x04, 0x38},
 	{0x05, 0x40},
 	{0x07, 0x40},
 	{0x0F, 0x4F},
 	{0x11, 0x21},
 	{0x12, 0x0B},
 	{0x13, 0x2F},
 	{0x14, 0x31},
 	{0x16, 0x02},
 	{0x21, 0xC4},
 	{0x22, 0x20},
 	{0x2C, 0x79},
 	{0x2D, 0x34},
 	{0x2F, 0x00},
 	{0x30, 0x28},
 	{0x31, 0x31},
 	{0x32, 0xDF},
 	{0x38, 0x01},
 	{0x39, 0x78},
 	{0x3B, 0x33},
 	{0x3C, 0x33},
 	{0x48, 0x90},
 	{0x51, 0x68},
 	{0x5E, 0x38},
 	{0x71, 0x00},
 	{0x72, 0x08},
 	{0x77, 0x00},
 	{0xC0, 0x21},
 	{0xC1, 0x10},
 	{0xE4, 0x1A},
 	{0xEA, 0x1F},
 	{0x77, 0x00},
 	{0x71, 0x00},
 	{0x71, 0x00},
 	{0x76, 0x0C},
 };

 static const int init_code_len = sizeof(init_code) / sizeof(u8[2]);

 static int jdvbt90502_init(struct dvb_frontend *fe)
 {
 	int i = -1;
 	int ret;
 	struct i2c_msg msg;

 	struct jdvbt90502_state *state = fe->demodulator_priv;

 	deb_fe("%s called.\n", __func__);

 	msg.addr = state->config.demod_address;
 	msg.flags = 0;
 	msg.len = 2;
 	for (i = 0; i < init_code_len; i++) {
 		msg.buf = init_code[i];
 		ret = i2c_transfer(state->i2c, &msg, 1);
 		if (ret != 1)
 			goto error;
 	}
 	fe->dtv_property_cache.delivery_system = SYS_ISDBT;
 	msleep(100);

 	return 0;

 error:
 	deb_fe("%s: init_code[%d] failed. ret==%d\n", __func__, i, ret);
 	return -EREMOTEIO;
 }


 static void jdvbt90502_release(struct dvb_frontend *fe)
 {
 	struct jdvbt90502_state *state = fe->demodulator_priv;
 	kfree(state);
 }


 static const struct dvb_frontend_ops jdvbt90502_ops;

 struct dvb_frontend *jdvbt90502_attach(struct dvb_usb_device *d)
 {
 	struct jdvbt90502_state *state = NULL;

 	deb_info("%s called.\n", __func__);

 	/* allocate memory for the internal state */
 	state = kzalloc(sizeof(struct jdvbt90502_state), GFP_KERNEL);
 	if (state == NULL)
 		goto error;

 	/* setup the state */
 	state->i2c = &d->i2c_adap;
 	state->config = friio_fe_config;

 	/* create dvb_frontend */
 	state->frontend.ops = jdvbt90502_ops;
 	state->frontend.demodulator_priv = state;

 	if (jdvbt90502_init(&state->frontend) < 0)
 		goto error;

 	return &state->frontend;

 error:
 	kfree(state);
 	return NULL;
 }

 static const struct dvb_frontend_ops jdvbt90502_ops = {
 	.delsys = { SYS_ISDBT },
 	.info = {
 		.name			= "Comtech JDVBT90502 ISDB-T",
 		.frequency_min		= 473000000, /* UHF 13ch, center */
 		.frequency_max		= 767142857, /* UHF 62ch, center */
 		.frequency_stepsize	= JDVBT90502_PLL_CLK / JDVBT90502_PLL_DIVIDER,
 		.frequency_tolerance	= 0,

 		/* NOTE: this driver ignores all parameters but frequency. */
 		.caps = FE_CAN_INVERSION_AUTO |
 			FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
 			FE_CAN_FEC_4_5 | FE_CAN_FEC_5_6 | FE_CAN_FEC_6_7 |
 			FE_CAN_FEC_7_8 | FE_CAN_FEC_8_9 | FE_CAN_FEC_AUTO |
 			FE_CAN_QAM_16 | FE_CAN_QAM_64 | FE_CAN_QAM_AUTO |
 			FE_CAN_TRANSMISSION_MODE_AUTO |
 			FE_CAN_GUARD_INTERVAL_AUTO |
 			FE_CAN_HIERARCHY_AUTO,
 	},

 	.release = jdvbt90502_release,

 	.init = jdvbt90502_init,
 	.write = _jdvbt90502_write,

 	.set_property = jdvbt90502_set_property,

 	.set_frontend = jdvbt90502_set_frontend,

 	.read_status = jdvbt90502_read_status,
 	.read_signal_strength = jdvbt90502_read_signal_strength,
 };
	/* DVB USB compliant Linux driver for the Friio USB2.0 ISDB-T receiver.
	*
	* Copyright (C) 2009 Akihiro Tsukada <tskd2@yahoo.co.jp>
	*
	* This module is based off the the gl861 and vp702x modules.
	*
	* 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, version 2.
	*
	* see Documentation/dvb/README.dvb-usb for more information
	*/
	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/slab.h>

	#include "friio.h"

	struct jdvbt90502_state {
	struct i2c_adapter *i2c;
	struct dvb_frontend frontend;
	struct jdvbt90502_config config;
	};

	/* NOTE: TC90502 has 16bit register-address? */
	/* register 0x0100 is used for reading PLL status, so reg is u16 here */
	static int jdvbt90502_reg_read(struct jdvbt90502_state *state,
	const u16 reg, u8 *buf, const size_t count)
	{
	int ret;
	u8 wbuf[3];
	struct i2c_msg msg[2];

	wbuf[0] = reg & 0xFF;
	wbuf[1] = 0;
	wbuf[2] = reg >> 8;

	msg[0].addr = state->config.demod_address;
	msg[0].flags = 0;
	msg[0].buf = wbuf;
	msg[0].len = sizeof(wbuf);

	msg[1].addr = msg[0].addr;
	msg[1].flags = I2C_M_RD;
	msg[1].buf = buf;
	msg[1].len = count;

	ret = i2c_transfer(state->i2c, msg, 2);
	if (ret != 2) {
	deb_fe(" reg read failed.\n");
	return -EREMOTEIO;
	}
	return 0;
	}

	/* currently 16bit register-address is not used, so reg is u8 here */
	static int jdvbt90502_single_reg_write(struct jdvbt90502_state *state,
	const u8 reg, const u8 val)
	{
	struct i2c_msg msg;
	u8 wbuf[2];

	wbuf[0] = reg;
	wbuf[1] = val;

	msg.addr = state->config.demod_address;
	msg.flags = 0;
	msg.buf = wbuf;
	msg.len = sizeof(wbuf);

	if (i2c_transfer(state->i2c, &msg, 1) != 1) {
	deb_fe(" reg write failed.");
	return -EREMOTEIO;
	}
	return 0;
	}

	static int _jdvbt90502_write(struct dvb_frontend *fe, const u8 buf[], int len)
	{
	struct jdvbt90502_state *state = fe->demodulator_priv;
	int err, i;
	for (i = 0; i < len - 1; i++) {
	err = jdvbt90502_single_reg_write(state,
	buf[0] + i, buf[i + 1]);
	if (err)
	return err;
	}

	return 0;
	}

	/* read pll status byte via the demodulator's I2C register */
	/* note: Win box reads it by 8B block at the I2C addr 0x30 from reg:0x80 */
	static int jdvbt90502_pll_read(struct jdvbt90502_state state, u8 result)
	{
	int ret;

	/* +1 for reading */
	u8 pll_addr_byte = (state->config.pll_address << 1) + 1;

	*result = 0;

	ret = jdvbt90502_single_reg_write(state, JDVBT90502_2ND_I2C_REG,
	pll_addr_byte);
	if (ret)
	goto error;

	ret = jdvbt90502_reg_read(state, 0x0100, result, 1);
	if (ret)
	goto error;

	deb_fe("PLL read val:%02x\n", *result);
	return 0;

	error:
	deb_fe("%s:ret == %d\n", __func__, ret);
	return -EREMOTEIO;
	}


	/* set pll frequency via the demodulator's I2C register */
	static int jdvbt90502_pll_set_freq(struct jdvbt90502_state *state, u32 freq)
	{
	int ret;
	int retry;
	u8 res1;
	u8 res2[9];

	u8 pll_freq_cmd[PLL_CMD_LEN];
	u8 pll_agc_cmd[PLL_CMD_LEN];
	struct i2c_msg msg[2];
	u32 f;

	deb_fe("%s: freq=%d, step=%d\n", __func__, freq,
	state->frontend.ops.info.frequency_stepsize);
	/* freq -> oscilator frequency conversion. */
	/* freq: 473,000,000 + n6,000,000 [+ 142857 (center freq. shift)] /
	f = freq / state->frontend.ops.info.frequency_stepsize;
	/* add 399[1/7 MHZ] = 57MHz for the IF */
	f += 399;
	/* add center frequency shift if necessary */
	if (f % 7 == 0)
	f++;
	pll_freq_cmd[DEMOD_REDIRECT_REG] = JDVBT90502_2ND_I2C_REG; /* 0xFE */
	pll_freq_cmd[ADDRESS_BYTE] = state->config.pll_address << 1;
	pll_freq_cmd[DIVIDER_BYTE1] = (f >> 8) & 0x7F;
	pll_freq_cmd[DIVIDER_BYTE2] = f & 0xFF;
	pll_freq_cmd[CONTROL_BYTE] = 0xB2; /* ref.divider:28, 4MHz/28=1/7MHz */
	pll_freq_cmd[BANDSWITCH_BYTE] = 0x08; /* UHF band */

	msg[0].addr = state->config.demod_address;
	msg[0].flags = 0;
	msg[0].buf = pll_freq_cmd;
	msg[0].len = sizeof(pll_freq_cmd);

	ret = i2c_transfer(state->i2c, &msg[0], 1);
	if (ret != 1)
	goto error;

	udelay(50);

	pll_agc_cmd[DEMOD_REDIRECT_REG] = pll_freq_cmd[DEMOD_REDIRECT_REG];
	pll_agc_cmd[ADDRESS_BYTE] = pll_freq_cmd[ADDRESS_BYTE];
	pll_agc_cmd[DIVIDER_BYTE1] = pll_freq_cmd[DIVIDER_BYTE1];
	pll_agc_cmd[DIVIDER_BYTE2] = pll_freq_cmd[DIVIDER_BYTE2];
	pll_agc_cmd[CONTROL_BYTE] = 0x9A; /* AGC_CTRL instead of BANDSWITCH */
	pll_agc_cmd[AGC_CTRL_BYTE] = 0x50;
	/* AGC Time Constant 2s, AGC take-over point:103dBuV(lowest) */

	msg[1].addr = msg[0].addr;
	msg[1].flags = 0;
	msg[1].buf = pll_agc_cmd;
	msg[1].len = sizeof(pll_agc_cmd);

	ret = i2c_transfer(state->i2c, &msg[1], 1);
	if (ret != 1)
	goto error;

	/* I don't know what these cmds are for, */
	/* but the USB log on a windows box contains them */
	ret = jdvbt90502_single_reg_write(state, 0x01, 0x40);
	ret \|= jdvbt90502_single_reg_write(state, 0x01, 0x00);
	if (ret)
	goto error;
	udelay(100);

	/* wait for the demod to be ready? */
	#define RETRY_COUNT 5
	for (retry = 0; retry < RETRY_COUNT; retry++) {
	ret = jdvbt90502_reg_read(state, 0x0096, &res1, 1);
	if (ret)
	goto error;
	/* if (res1 != 0x00) goto error; */
	ret = jdvbt90502_reg_read(state, 0x00B0, res2, sizeof(res2));
	if (ret)
	goto error;
	if (res2[0] >= 0xA7)
	break;
	msleep(100);
	}
	if (retry >= RETRY_COUNT) {
	deb_fe("%s: FE does not get ready after freq setting.\n",
	__func__);
	return -EREMOTEIO;
	}

	return 0;
	error:
	deb_fe("%s:ret == %d\n", __func__, ret);
	return -EREMOTEIO;
	}

	static int jdvbt90502_read_status(struct dvb_frontend *fe,
	enum fe_status *state)
	{
	u8 result;
	int ret;

	*state = FE_HAS_SIGNAL;

	ret = jdvbt90502_pll_read(fe->demodulator_priv, &result);
	if (ret) {
	deb_fe("%s:ret == %d\n", __func__, ret);
	return -EREMOTEIO;
	}

	*state = FE_HAS_SIGNAL
	\| FE_HAS_CARRIER
	\| FE_HAS_VITERBI
	\| FE_HAS_SYNC;

	if (result & PLL_STATUS_LOCKED)
	*state \|= FE_HAS_LOCK;

	return 0;
	}

	static int jdvbt90502_read_signal_strength(struct dvb_frontend *fe,
	u16 *strength)
	{
	int ret;
	u8 rbuf[37];

	*strength = 0;

	/* status register (incl. signal strength) : 0x89 */
	/* TODO: read just the necessary registers [0x8B..0x8D]? */
	ret = jdvbt90502_reg_read(fe->demodulator_priv, 0x0089,
	rbuf, sizeof(rbuf));

	if (ret) {
	deb_fe("%s:ret == %d\n", __func__, ret);
	return -EREMOTEIO;
	}

	/* signal_strength: rbuf[2-4] (24bit BE), use lower 16bit for now. */
	*strength = (rbuf[3] << 8) + rbuf[4];
	if (rbuf[2])
	*strength = 0xffff;

	return 0;
	}


	/* filter out un-supported properties to notify users */
	static int jdvbt90502_set_property(struct dvb_frontend *fe,
	struct dtv_property *tvp)
	{
	int r = 0;

	switch (tvp->cmd) {
	case DTV_DELIVERY_SYSTEM:
	if (tvp->u.data != SYS_ISDBT)
	r = -EINVAL;
	break;
	case DTV_CLEAR:
	case DTV_TUNE:
	case DTV_FREQUENCY:
	break;
	default:
	r = -EINVAL;
	}
	return r;
	}

	static int jdvbt90502_set_frontend(struct dvb_frontend *fe)
	{
	struct dtv_frontend_properties *p = &fe->dtv_property_cache;

	/**
	* NOTE: ignore all the parameters except frequency.
	* others should be fixed to the proper value for ISDB-T,
	* but don't check here.
	*/

	struct jdvbt90502_state *state = fe->demodulator_priv;
	int ret;

	deb_fe("%s: Freq:%d\n", __func__, p->frequency);

	/* This driver only works on auto mode */
	p->inversion = INVERSION_AUTO;
	p->bandwidth_hz = 6000000;
	p->code_rate_HP = FEC_AUTO;
	p->code_rate_LP = FEC_AUTO;
	p->modulation = QAM_64;
	p->transmission_mode = TRANSMISSION_MODE_AUTO;
	p->guard_interval = GUARD_INTERVAL_AUTO;
	p->hierarchy = HIERARCHY_AUTO;
	p->delivery_system = SYS_ISDBT;

	ret = jdvbt90502_pll_set_freq(state, p->frequency);
	if (ret) {
	deb_fe("%s:ret == %d\n", __func__, ret);
	return -EREMOTEIO;
	}

	return 0;
	}


	/**
	* (reg, val) commad list to initialize this module.
	* captured on a Windows box.
	*/
	static u8 init_code[][2] = {
	{0x01, 0x40},
	{0x04, 0x38},
	{0x05, 0x40},
	{0x07, 0x40},
	{0x0F, 0x4F},
	{0x11, 0x21},
	{0x12, 0x0B},
	{0x13, 0x2F},
	{0x14, 0x31},
	{0x16, 0x02},
	{0x21, 0xC4},
	{0x22, 0x20},
	{0x2C, 0x79},
	{0x2D, 0x34},
	{0x2F, 0x00},
	{0x30, 0x28},
	{0x31, 0x31},
	{0x32, 0xDF},
	{0x38, 0x01},
	{0x39, 0x78},
	{0x3B, 0x33},
	{0x3C, 0x33},
	{0x48, 0x90},
	{0x51, 0x68},
	{0x5E, 0x38},
	{0x71, 0x00},
	{0x72, 0x08},
	{0x77, 0x00},
	{0xC0, 0x21},
	{0xC1, 0x10},
	{0xE4, 0x1A},
	{0xEA, 0x1F},
	{0x77, 0x00},
	{0x71, 0x00},
	{0x71, 0x00},
	{0x76, 0x0C},
	};

	static const int init_code_len = sizeof(init_code) / sizeof(u8[2]);

	static int jdvbt90502_init(struct dvb_frontend *fe)
	{
	int i = -1;
	int ret;
	struct i2c_msg msg;

	struct jdvbt90502_state *state = fe->demodulator_priv;

	deb_fe("%s called.\n", __func__);

	msg.addr = state->config.demod_address;
	msg.flags = 0;
	msg.len = 2;
	for (i = 0; i < init_code_len; i++) {
	msg.buf = init_code[i];
	ret = i2c_transfer(state->i2c, &msg, 1);
	if (ret != 1)
	goto error;
	}
	fe->dtv_property_cache.delivery_system = SYS_ISDBT;
	msleep(100);

	return 0;

	error:
	deb_fe("%s: init_code[%d] failed. ret==%d\n", __func__, i, ret);
	return -EREMOTEIO;
	}


	static void jdvbt90502_release(struct dvb_frontend *fe)
	{
	struct jdvbt90502_state *state = fe->demodulator_priv;
	kfree(state);
	}


	static const struct dvb_frontend_ops jdvbt90502_ops;

	struct dvb_frontend jdvbt90502_attach(struct dvb_usb_device d)
	{
	struct jdvbt90502_state *state = NULL;

	deb_info("%s called.\n", __func__);

	/* allocate memory for the internal state */
	state = kzalloc(sizeof(struct jdvbt90502_state), GFP_KERNEL);
	if (state == NULL)
	goto error;

	/* setup the state */
	state->i2c = &d->i2c_adap;
	state->config = friio_fe_config;

	/* create dvb_frontend */
	state->frontend.ops = jdvbt90502_ops;
	state->frontend.demodulator_priv = state;

	if (jdvbt90502_init(&state->frontend) < 0)
	goto error;

	return &state->frontend;

	error:
	kfree(state);
	return NULL;
	}

	static const struct dvb_frontend_ops jdvbt90502_ops = {
	.delsys = { SYS_ISDBT },
	.info = {
	.name = "Comtech JDVBT90502 ISDB-T",
	.frequency_min = 473000000, /* UHF 13ch, center */
	.frequency_max = 767142857, /* UHF 62ch, center */
	.frequency_stepsize = JDVBT90502_PLL_CLK / JDVBT90502_PLL_DIVIDER,
	.frequency_tolerance = 0,

	/* NOTE: this driver ignores all parameters but frequency. */
	.caps = FE_CAN_INVERSION_AUTO \|
	FE_CAN_FEC_1_2 \| FE_CAN_FEC_2_3 \| FE_CAN_FEC_3_4 \|
	FE_CAN_FEC_4_5 \| FE_CAN_FEC_5_6 \| FE_CAN_FEC_6_7 \|
	FE_CAN_FEC_7_8 \| FE_CAN_FEC_8_9 \| FE_CAN_FEC_AUTO \|
	FE_CAN_QAM_16 \| FE_CAN_QAM_64 \| FE_CAN_QAM_AUTO \|
	FE_CAN_TRANSMISSION_MODE_AUTO \|
	FE_CAN_GUARD_INTERVAL_AUTO \|
	FE_CAN_HIERARCHY_AUTO,
	},

	.release = jdvbt90502_release,

	.init = jdvbt90502_init,
	.write = _jdvbt90502_write,

	.set_property = jdvbt90502_set_property,

	.set_frontend = jdvbt90502_set_frontend,

	.read_status = jdvbt90502_read_status,
	.read_signal_strength = jdvbt90502_read_signal_strength,
	};