drivers/media/dvb-frontends/sp887x.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
    Driver for the Spase sp887x demodulator
 */

 /*
  * This driver needs external firmware. Please use the command
  * "<kerneldir>/scripts/get_dvb_firmware sp887x" to
  * download/extract it, and then copy it to /usr/lib/hotplug/firmware
  * or /lib/firmware (depending on configuration of firmware hotplug).
  */
 #define SP887X_DEFAULT_FIRMWARE "dvb-fe-sp887x.fw"

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/firmware.h>
 #include <linux/string.h>
 #include <linux/slab.h>

 #include <media/dvb_frontend.h>
 #include "sp887x.h"


 struct sp887x_state {
 	struct i2c_adapter* i2c;
 	const struct sp887x_config* config;
 	struct dvb_frontend frontend;

 	/* demodulator private data */
 	u8 initialised:1;
 };

 static int debug;
 #define dprintk(args...) \
 	do { \
 		if (debug) printk(KERN_DEBUG "sp887x: " args); \
 	} while (0)

 static int i2c_writebytes (struct sp887x_state* state, u8 *buf, u8 len)
 {
 	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, .len = len };
 	int err;

 	if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
 		printk ("%s: i2c write error (addr %02x, err == %i)\n",
 			__func__, state->config->demod_address, err);
 		return -EREMOTEIO;
 	}

 	return 0;
 }

 static int sp887x_writereg (struct sp887x_state* state, u16 reg, u16 data)
 {
 	u8 b0 [] = { reg >> 8 , reg & 0xff, data >> 8, data & 0xff };
 	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 4 };
 	int ret;

 	if ((ret = i2c_transfer(state->i2c, &msg, 1)) != 1) {
 		/*
 		 *  in case of soft reset we ignore ACK errors...
 		 */
 		if (!(reg == 0xf1a && data == 0x000 &&
 			(ret == -EREMOTEIO || ret == -EFAULT)))
 		{
 			printk("%s: writereg error (reg %03x, data %03x, ret == %i)\n",
 			       __func__, reg & 0xffff, data & 0xffff, ret);
 			return ret;
 		}
 	}

 	return 0;
 }

 static int sp887x_readreg (struct sp887x_state* state, u16 reg)
 {
 	u8 b0 [] = { reg >> 8 , reg & 0xff };
 	u8 b1 [2];
 	int ret;
 	struct i2c_msg msg[] = {{ .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 2 },
 			 { .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 2 }};

 	if ((ret = i2c_transfer(state->i2c, msg, 2)) != 2) {
 		printk("%s: readreg error (ret == %i)\n", __func__, ret);
 		return -1;
 	}

 	return (((b1[0] << 8) | b1[1]) & 0xfff);
 }

 static void sp887x_microcontroller_stop (struct sp887x_state* state)
 {
 	dprintk("%s\n", __func__);
 	sp887x_writereg(state, 0xf08, 0x000);
 	sp887x_writereg(state, 0xf09, 0x000);

 	/* microcontroller STOP */
 	sp887x_writereg(state, 0xf00, 0x000);
 }

 static void sp887x_microcontroller_start (struct sp887x_state* state)
 {
 	dprintk("%s\n", __func__);
 	sp887x_writereg(state, 0xf08, 0x000);
 	sp887x_writereg(state, 0xf09, 0x000);

 	/* microcontroller START */
 	sp887x_writereg(state, 0xf00, 0x001);
 }

 static void sp887x_setup_agc (struct sp887x_state* state)
 {
 	/* setup AGC parameters */
 	dprintk("%s\n", __func__);
 	sp887x_writereg(state, 0x33c, 0x054);
 	sp887x_writereg(state, 0x33b, 0x04c);
 	sp887x_writereg(state, 0x328, 0x000);
 	sp887x_writereg(state, 0x327, 0x005);
 	sp887x_writereg(state, 0x326, 0x001);
 	sp887x_writereg(state, 0x325, 0x001);
 	sp887x_writereg(state, 0x324, 0x001);
 	sp887x_writereg(state, 0x318, 0x050);
 	sp887x_writereg(state, 0x317, 0x3fe);
 	sp887x_writereg(state, 0x316, 0x001);
 	sp887x_writereg(state, 0x313, 0x005);
 	sp887x_writereg(state, 0x312, 0x002);
 	sp887x_writereg(state, 0x306, 0x000);
 	sp887x_writereg(state, 0x303, 0x000);
 }

 #define BLOCKSIZE 30
 #define FW_SIZE 0x4000
 /*
  *  load firmware and setup MPEG interface...
  */
 static int sp887x_initial_setup (struct dvb_frontend* fe, const struct firmware *fw)
 {
 	struct sp887x_state* state = fe->demodulator_priv;
 	u8 buf [BLOCKSIZE + 2];
 	int i;
 	int fw_size = fw->size;
 	const unsigned char *mem = fw->data;

 	dprintk("%s\n", __func__);

 	/* ignore the first 10 bytes, then we expect 0x4000 bytes of firmware */
 	if (fw_size < FW_SIZE + 10)
 		return -ENODEV;

 	mem = fw->data + 10;

 	/* soft reset */
 	sp887x_writereg(state, 0xf1a, 0x000);

 	sp887x_microcontroller_stop (state);

 	printk ("%s: firmware upload... ", __func__);

 	/* setup write pointer to -1 (end of memory) */
 	/* bit 0x8000 in address is set to enable 13bit mode */
 	sp887x_writereg(state, 0x8f08, 0x1fff);

 	/* dummy write (wrap around to start of memory) */
 	sp887x_writereg(state, 0x8f0a, 0x0000);

 	for (i = 0; i < FW_SIZE; i += BLOCKSIZE) {
 		int c = BLOCKSIZE;
 		int err;

 		if (c > FW_SIZE - i)
 			c = FW_SIZE - i;

 		/* bit 0x8000 in address is set to enable 13bit mode */
 		/* bit 0x4000 enables multibyte read/write transfers */
 		/* write register is 0xf0a */
 		buf[0] = 0xcf;
 		buf[1] = 0x0a;

 		memcpy(&buf[2], mem + i, c);

 		if ((err = i2c_writebytes (state, buf, c+2)) < 0) {
 			printk ("failed.\n");
 			printk ("%s: i2c error (err == %i)\n", __func__, err);
 			return err;
 		}
 	}

 	/* don't write RS bytes between packets */
 	sp887x_writereg(state, 0xc13, 0x001);

 	/* suppress clock if (!data_valid) */
 	sp887x_writereg(state, 0xc14, 0x000);

 	/* setup MPEG interface... */
 	sp887x_writereg(state, 0xc1a, 0x872);
 	sp887x_writereg(state, 0xc1b, 0x001);
 	sp887x_writereg(state, 0xc1c, 0x000); /* parallel mode (serial mode == 1) */
 	sp887x_writereg(state, 0xc1a, 0x871);

 	/* ADC mode, 2 for MT8872, 3 for SP8870/SP8871 */
 	sp887x_writereg(state, 0x301, 0x002);

 	sp887x_setup_agc(state);

 	/* bit 0x010: enable data valid signal */
 	sp887x_writereg(state, 0xd00, 0x010);
 	sp887x_writereg(state, 0x0d1, 0x000);
 	return 0;
 };

 static int configure_reg0xc05(struct dtv_frontend_properties *p, u16 *reg0xc05)
 {
 	int known_parameters = 1;

 	*reg0xc05 = 0x000;

 	switch (p->modulation) {
 	case QPSK:
 		break;
 	case QAM_16:
 		*reg0xc05 |= (1 << 10);
 		break;
 	case QAM_64:
 		*reg0xc05 |= (2 << 10);
 		break;
 	case QAM_AUTO:
 		known_parameters = 0;
 		break;
 	default:
 		return -EINVAL;
 	}

 	switch (p->hierarchy) {
 	case HIERARCHY_NONE:
 		break;
 	case HIERARCHY_1:
 		*reg0xc05 |= (1 << 7);
 		break;
 	case HIERARCHY_2:
 		*reg0xc05 |= (2 << 7);
 		break;
 	case HIERARCHY_4:
 		*reg0xc05 |= (3 << 7);
 		break;
 	case HIERARCHY_AUTO:
 		known_parameters = 0;
 		break;
 	default:
 		return -EINVAL;
 	}

 	switch (p->code_rate_HP) {
 	case FEC_1_2:
 		break;
 	case FEC_2_3:
 		*reg0xc05 |= (1 << 3);
 		break;
 	case FEC_3_4:
 		*reg0xc05 |= (2 << 3);
 		break;
 	case FEC_5_6:
 		*reg0xc05 |= (3 << 3);
 		break;
 	case FEC_7_8:
 		*reg0xc05 |= (4 << 3);
 		break;
 	case FEC_AUTO:
 		known_parameters = 0;
 		break;
 	default:
 		return -EINVAL;
 	}

 	if (known_parameters)
 		*reg0xc05 |= (2 << 1);	/* use specified parameters */
 	else
 		*reg0xc05 |= (1 << 1);	/* enable autoprobing */

 	return 0;
 }

 /*
  *  estimates division of two 24bit numbers,
  *  derived from the ves1820/stv0299 driver code
  */
 static void divide (int n, int d, int *quotient_i, int *quotient_f)
 {
 	unsigned int q, r;

 	r = (n % d) << 8;
 	q = (r / d);

 	if (quotient_i)
 		*quotient_i = q;

 	if (quotient_f) {
 		r = (r % d) << 8;
 		q = (q << 8) | (r / d);
 		r = (r % d) << 8;
 		*quotient_f = (q << 8) | (r / d);
 	}
 }

 static void sp887x_correct_offsets (struct sp887x_state* state,
 				    struct dtv_frontend_properties *p,
 				    int actual_freq)
 {
 	static const u32 srate_correction [] = { 1879617, 4544878, 8098561 };
 	int bw_index;
 	int freq_offset = actual_freq - p->frequency;
 	int sysclock = 61003; //[kHz]
 	int ifreq = 36000000;
 	int freq;
 	int frequency_shift;

 	switch (p->bandwidth_hz) {
 	default:
 	case 8000000:
 		bw_index = 0;
 		break;
 	case 7000000:
 		bw_index = 1;
 		break;
 	case 6000000:
 		bw_index = 2;
 		break;
 	}

 	if (p->inversion == INVERSION_ON)
 		freq = ifreq - freq_offset;
 	else
 		freq = ifreq + freq_offset;

 	divide(freq / 333, sysclock, NULL, &frequency_shift);

 	if (p->inversion == INVERSION_ON)
 		frequency_shift = -frequency_shift;

 	/* sample rate correction */
 	sp887x_writereg(state, 0x319, srate_correction[bw_index] >> 12);
 	sp887x_writereg(state, 0x31a, srate_correction[bw_index] & 0xfff);

 	/* carrier offset correction */
 	sp887x_writereg(state, 0x309, frequency_shift >> 12);
 	sp887x_writereg(state, 0x30a, frequency_shift & 0xfff);
 }

 static int sp887x_setup_frontend_parameters(struct dvb_frontend *fe)
 {
 	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
 	struct sp887x_state* state = fe->demodulator_priv;
 	unsigned actual_freq;
 	int err;
 	u16 val, reg0xc05;

 	if (p->bandwidth_hz != 8000000 &&
 	    p->bandwidth_hz != 7000000 &&
 	    p->bandwidth_hz != 6000000)
 		return -EINVAL;

 	if ((err = configure_reg0xc05(p, &reg0xc05)))
 		return err;

 	sp887x_microcontroller_stop(state);

 	/* setup the PLL */
 	if (fe->ops.tuner_ops.set_params) {
 		fe->ops.tuner_ops.set_params(fe);
 		if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
 	}
 	if (fe->ops.tuner_ops.get_frequency) {
 		fe->ops.tuner_ops.get_frequency(fe, &actual_freq);
 		if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
 	} else {
 		actual_freq = p->frequency;
 	}

 	/* read status reg in order to clear <pending irqs */
 	sp887x_readreg(state, 0x200);

 	sp887x_correct_offsets(state, p, actual_freq);

 	/* filter for 6/7/8 Mhz channel */
 	if (p->bandwidth_hz == 6000000)
 		val = 2;
 	else if (p->bandwidth_hz == 7000000)
 		val = 1;
 	else
 		val = 0;

 	sp887x_writereg(state, 0x311, val);

 	/* scan order: 2k first = 0, 8k first = 1 */
 	if (p->transmission_mode == TRANSMISSION_MODE_2K)
 		sp887x_writereg(state, 0x338, 0x000);
 	else
 		sp887x_writereg(state, 0x338, 0x001);

 	sp887x_writereg(state, 0xc05, reg0xc05);

 	if (p->bandwidth_hz == 6000000)
 		val = 2 << 3;
 	else if (p->bandwidth_hz == 7000000)
 		val = 3 << 3;
 	else
 		val = 0 << 3;

 	/* enable OFDM and SAW bits as lock indicators in sync register 0xf17,
 	 * optimize algorithm for given bandwidth...
 	 */
 	sp887x_writereg(state, 0xf14, 0x160 | val);
 	sp887x_writereg(state, 0xf15, 0x000);

 	sp887x_microcontroller_start(state);
 	return 0;
 }

 static int sp887x_read_status(struct dvb_frontend *fe, enum fe_status *status)
 {
 	struct sp887x_state* state = fe->demodulator_priv;
 	u16 snr12 = sp887x_readreg(state, 0xf16);
 	u16 sync0x200 = sp887x_readreg(state, 0x200);
 	u16 sync0xf17 = sp887x_readreg(state, 0xf17);

 	*status = 0;

 	if (snr12 > 0x00f)
 		*status |= FE_HAS_SIGNAL;

 	//if (sync0x200 & 0x004)
 	//	*status |= FE_HAS_SYNC | FE_HAS_CARRIER;

 	//if (sync0x200 & 0x008)
 	//	*status |= FE_HAS_VITERBI;

 	if ((sync0xf17 & 0x00f) == 0x002) {
 		*status |= FE_HAS_LOCK;
 		*status |= FE_HAS_VITERBI | FE_HAS_SYNC | FE_HAS_CARRIER;
 	}

 	if (sync0x200 & 0x001) {	/* tuner adjustment requested...*/
 		int steps = (sync0x200 >> 4) & 0x00f;
 		if (steps & 0x008)
 			steps = -steps;
 		dprintk("sp887x: implement tuner adjustment (%+i steps)!!\n",
 		       steps);
 	}

 	return 0;
 }

 static int sp887x_read_ber(struct dvb_frontend* fe, u32* ber)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	*ber = (sp887x_readreg(state, 0xc08) & 0x3f) |
 	       (sp887x_readreg(state, 0xc07) << 6);
 	sp887x_writereg(state, 0xc08, 0x000);
 	sp887x_writereg(state, 0xc07, 0x000);
 	if (*ber >= 0x3fff0)
 		*ber = ~0;

 	return 0;
 }

 static int sp887x_read_signal_strength(struct dvb_frontend* fe, u16* strength)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	u16 snr12 = sp887x_readreg(state, 0xf16);
 	u32 signal = 3 * (snr12 << 4);
 	*strength = (signal < 0xffff) ? signal : 0xffff;

 	return 0;
 }

 static int sp887x_read_snr(struct dvb_frontend* fe, u16* snr)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	u16 snr12 = sp887x_readreg(state, 0xf16);
 	*snr = (snr12 << 4) | (snr12 >> 8);

 	return 0;
 }

 static int sp887x_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	*ucblocks = sp887x_readreg(state, 0xc0c);
 	if (*ucblocks == 0xfff)
 		*ucblocks = ~0;

 	return 0;
 }

 static int sp887x_i2c_gate_ctrl(struct dvb_frontend* fe, int enable)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	if (enable) {
 		return sp887x_writereg(state, 0x206, 0x001);
 	} else {
 		return sp887x_writereg(state, 0x206, 0x000);
 	}
 }

 static int sp887x_sleep(struct dvb_frontend* fe)
 {
 	struct sp887x_state* state = fe->demodulator_priv;

 	/* tristate TS output and disable interface pins */
 	sp887x_writereg(state, 0xc18, 0x000);

 	return 0;
 }

 static int sp887x_init(struct dvb_frontend* fe)
 {
 	struct sp887x_state* state = fe->demodulator_priv;
 	const struct firmware *fw = NULL;
 	int ret;

 	if (!state->initialised) {
 		/* request the firmware, this will block until someone uploads it */
 		printk("sp887x: waiting for firmware upload (%s)...\n", SP887X_DEFAULT_FIRMWARE);
 		ret = state->config->request_firmware(fe, &fw, SP887X_DEFAULT_FIRMWARE);
 		if (ret) {
 			printk("sp887x: no firmware upload (timeout or file not found?)\n");
 			return ret;
 		}

 		ret = sp887x_initial_setup(fe, fw);
 		release_firmware(fw);
 		if (ret) {
 			printk("sp887x: writing firmware to device failed\n");
 			return ret;
 		}
 		printk("sp887x: firmware upload complete\n");
 		state->initialised = 1;
 	}

 	/* enable TS output and interface pins */
 	sp887x_writereg(state, 0xc18, 0x00d);

 	return 0;
 }

 static int sp887x_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings)
 {
 	fesettings->min_delay_ms = 350;
 	fesettings->step_size = 166666*2;
 	fesettings->max_drift = (166666*2)+1;
 	return 0;
 }

 static void sp887x_release(struct dvb_frontend* fe)
 {
 	struct sp887x_state* state = fe->demodulator_priv;
 	kfree(state);
 }

 static const struct dvb_frontend_ops sp887x_ops;

 struct dvb_frontend* sp887x_attach(const struct sp887x_config* config,
 				   struct i2c_adapter* i2c)
 {
 	struct sp887x_state* state = NULL;

 	/* allocate memory for the internal state */
 	state = kzalloc(sizeof(struct sp887x_state), GFP_KERNEL);
 	if (state == NULL) goto error;

 	/* setup the state */
 	state->config = config;
 	state->i2c = i2c;
 	state->initialised = 0;

 	/* check if the demod is there */
 	if (sp887x_readreg(state, 0x0200) < 0) goto error;

 	/* create dvb_frontend */
 	memcpy(&state->frontend.ops, &sp887x_ops, sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;
 	return &state->frontend;

 error:
 	kfree(state);
 	return NULL;
 }

 static const struct dvb_frontend_ops sp887x_ops = {
 	.delsys = { SYS_DVBT },
 	.info = {
 		.name = "Spase SP887x DVB-T",
 		.frequency_min_hz =  50500 * kHz,
 		.frequency_max_hz = 858000 * kHz,
 		.frequency_stepsize_hz = 166666,
 		.caps = FE_CAN_FEC_1_2 | FE_CAN_FEC_2_3 | FE_CAN_FEC_3_4 |
 			FE_CAN_FEC_5_6 | FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
 			FE_CAN_QPSK | FE_CAN_QAM_16 | FE_CAN_QAM_64 |
 			FE_CAN_RECOVER
 	},

 	.release = sp887x_release,

 	.init = sp887x_init,
 	.sleep = sp887x_sleep,
 	.i2c_gate_ctrl = sp887x_i2c_gate_ctrl,

 	.set_frontend = sp887x_setup_frontend_parameters,
 	.get_tune_settings = sp887x_get_tune_settings,

 	.read_status = sp887x_read_status,
 	.read_ber = sp887x_read_ber,
 	.read_signal_strength = sp887x_read_signal_strength,
 	.read_snr = sp887x_read_snr,
 	.read_ucblocks = sp887x_read_ucblocks,
 };

 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");

 MODULE_DESCRIPTION("Spase sp887x DVB-T demodulator driver");
 MODULE_LICENSE("GPL");

 EXPORT_SYMBOL(sp887x_attach);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	Driver for the Spase sp887x demodulator
	*/

	/*
	* This driver needs external firmware. Please use the command
	* "<kerneldir>/scripts/get_dvb_firmware sp887x" to
	* download/extract it, and then copy it to /usr/lib/hotplug/firmware
	* or /lib/firmware (depending on configuration of firmware hotplug).
	*/
	#define SP887X_DEFAULT_FIRMWARE "dvb-fe-sp887x.fw"

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/device.h>
	#include <linux/firmware.h>
	#include <linux/string.h>
	#include <linux/slab.h>

	#include <media/dvb_frontend.h>
	#include "sp887x.h"


	struct sp887x_state {
	struct i2c_adapter* i2c;
	const struct sp887x_config* config;
	struct dvb_frontend frontend;

	/* demodulator private data */
	u8 initialised:1;
	};

	static int debug;
	#define dprintk(args...) \
	do { \
	if (debug) printk(KERN_DEBUG "sp887x: " args); \
	} while (0)

	static int i2c_writebytes (struct sp887x_state* state, u8 *buf, u8 len)
	{
	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = buf, .len = len };
	int err;

	if ((err = i2c_transfer (state->i2c, &msg, 1)) != 1) {
	printk ("%s: i2c write error (addr %02x, err == %i)\n",
	__func__, state->config->demod_address, err);
	return -EREMOTEIO;
	}

	return 0;
	}

	static int sp887x_writereg (struct sp887x_state* state, u16 reg, u16 data)
	{
	u8 b0 [] = { reg >> 8 , reg & 0xff, data >> 8, data & 0xff };
	struct i2c_msg msg = { .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 4 };
	int ret;

	if ((ret = i2c_transfer(state->i2c, &msg, 1)) != 1) {
	/*
	* in case of soft reset we ignore ACK errors...
	*/
	if (!(reg == 0xf1a && data == 0x000 &&
	(ret == -EREMOTEIO \|\| ret == -EFAULT)))
	{
	printk("%s: writereg error (reg %03x, data %03x, ret == %i)\n",
	__func__, reg & 0xffff, data & 0xffff, ret);
	return ret;
	}
	}

	return 0;
	}

	static int sp887x_readreg (struct sp887x_state* state, u16 reg)
	{
	u8 b0 [] = { reg >> 8 , reg & 0xff };
	u8 b1 [2];
	int ret;
	struct i2c_msg msg[] = {{ .addr = state->config->demod_address, .flags = 0, .buf = b0, .len = 2 },
	{ .addr = state->config->demod_address, .flags = I2C_M_RD, .buf = b1, .len = 2 }};

	if ((ret = i2c_transfer(state->i2c, msg, 2)) != 2) {
	printk("%s: readreg error (ret == %i)\n", __func__, ret);
	return -1;
	}

	return (((b1[0] << 8) \| b1[1]) & 0xfff);
	}

	static void sp887x_microcontroller_stop (struct sp887x_state* state)
	{
	dprintk("%s\n", __func__);
	sp887x_writereg(state, 0xf08, 0x000);
	sp887x_writereg(state, 0xf09, 0x000);

	/* microcontroller STOP */
	sp887x_writereg(state, 0xf00, 0x000);
	}

	static void sp887x_microcontroller_start (struct sp887x_state* state)
	{
	dprintk("%s\n", __func__);
	sp887x_writereg(state, 0xf08, 0x000);
	sp887x_writereg(state, 0xf09, 0x000);

	/* microcontroller START */
	sp887x_writereg(state, 0xf00, 0x001);
	}

	static void sp887x_setup_agc (struct sp887x_state* state)
	{
	/* setup AGC parameters */
	dprintk("%s\n", __func__);
	sp887x_writereg(state, 0x33c, 0x054);
	sp887x_writereg(state, 0x33b, 0x04c);
	sp887x_writereg(state, 0x328, 0x000);
	sp887x_writereg(state, 0x327, 0x005);
	sp887x_writereg(state, 0x326, 0x001);
	sp887x_writereg(state, 0x325, 0x001);
	sp887x_writereg(state, 0x324, 0x001);
	sp887x_writereg(state, 0x318, 0x050);
	sp887x_writereg(state, 0x317, 0x3fe);
	sp887x_writereg(state, 0x316, 0x001);
	sp887x_writereg(state, 0x313, 0x005);
	sp887x_writereg(state, 0x312, 0x002);
	sp887x_writereg(state, 0x306, 0x000);
	sp887x_writereg(state, 0x303, 0x000);
	}

	#define BLOCKSIZE 30
	#define FW_SIZE 0x4000
	/*
	* load firmware and setup MPEG interface...
	*/
	static int sp887x_initial_setup (struct dvb_frontend* fe, const struct firmware *fw)
	{
	struct sp887x_state* state = fe->demodulator_priv;
	u8 buf [BLOCKSIZE + 2];
	int i;
	int fw_size = fw->size;
	const unsigned char *mem = fw->data;

	dprintk("%s\n", __func__);

	/* ignore the first 10 bytes, then we expect 0x4000 bytes of firmware */
	if (fw_size < FW_SIZE + 10)
	return -ENODEV;

	mem = fw->data + 10;

	/* soft reset */
	sp887x_writereg(state, 0xf1a, 0x000);

	sp887x_microcontroller_stop (state);

	printk ("%s: firmware upload... ", __func__);

	/* setup write pointer to -1 (end of memory) */
	/* bit 0x8000 in address is set to enable 13bit mode */
	sp887x_writereg(state, 0x8f08, 0x1fff);

	/* dummy write (wrap around to start of memory) */
	sp887x_writereg(state, 0x8f0a, 0x0000);

	for (i = 0; i < FW_SIZE; i += BLOCKSIZE) {
	int c = BLOCKSIZE;
	int err;

	if (c > FW_SIZE - i)
	c = FW_SIZE - i;

	/* bit 0x8000 in address is set to enable 13bit mode */
	/* bit 0x4000 enables multibyte read/write transfers */
	/* write register is 0xf0a */
	buf[0] = 0xcf;
	buf[1] = 0x0a;

	memcpy(&buf[2], mem + i, c);

	if ((err = i2c_writebytes (state, buf, c+2)) < 0) {
	printk ("failed.\n");
	printk ("%s: i2c error (err == %i)\n", __func__, err);
	return err;
	}
	}

	/* don't write RS bytes between packets */
	sp887x_writereg(state, 0xc13, 0x001);

	/* suppress clock if (!data_valid) */
	sp887x_writereg(state, 0xc14, 0x000);

	/* setup MPEG interface... */
	sp887x_writereg(state, 0xc1a, 0x872);
	sp887x_writereg(state, 0xc1b, 0x001);
	sp887x_writereg(state, 0xc1c, 0x000); /* parallel mode (serial mode == 1) */
	sp887x_writereg(state, 0xc1a, 0x871);

	/* ADC mode, 2 for MT8872, 3 for SP8870/SP8871 */
	sp887x_writereg(state, 0x301, 0x002);

	sp887x_setup_agc(state);

	/* bit 0x010: enable data valid signal */
	sp887x_writereg(state, 0xd00, 0x010);
	sp887x_writereg(state, 0x0d1, 0x000);
	return 0;
	};

	static int configure_reg0xc05(struct dtv_frontend_properties p, u16 reg0xc05)
	{
	int known_parameters = 1;

	*reg0xc05 = 0x000;

	switch (p->modulation) {
	case QPSK:
	break;
	case QAM_16:
	*reg0xc05 \|= (1 << 10);
	break;
	case QAM_64:
	*reg0xc05 \|= (2 << 10);
	break;
	case QAM_AUTO:
	known_parameters = 0;
	break;
	default:
	return -EINVAL;
	}

	switch (p->hierarchy) {
	case HIERARCHY_NONE:
	break;
	case HIERARCHY_1:
	*reg0xc05 \|= (1 << 7);
	break;
	case HIERARCHY_2:
	*reg0xc05 \|= (2 << 7);
	break;
	case HIERARCHY_4:
	*reg0xc05 \|= (3 << 7);
	break;
	case HIERARCHY_AUTO:
	known_parameters = 0;
	break;
	default:
	return -EINVAL;
	}

	switch (p->code_rate_HP) {
	case FEC_1_2:
	break;
	case FEC_2_3:
	*reg0xc05 \|= (1 << 3);
	break;
	case FEC_3_4:
	*reg0xc05 \|= (2 << 3);
	break;
	case FEC_5_6:
	*reg0xc05 \|= (3 << 3);
	break;
	case FEC_7_8:
	*reg0xc05 \|= (4 << 3);
	break;
	case FEC_AUTO:
	known_parameters = 0;
	break;
	default:
	return -EINVAL;
	}

	if (known_parameters)
	reg0xc05 \|= (2 << 1); / use specified parameters */
	else
	reg0xc05 \|= (1 << 1); / enable autoprobing */

	return 0;
	}

	/*
	* estimates division of two 24bit numbers,
	* derived from the ves1820/stv0299 driver code
	*/
	static void divide (int n, int d, int quotient_i, int quotient_f)
	{
	unsigned int q, r;

	r = (n % d) << 8;
	q = (r / d);

	if (quotient_i)
	*quotient_i = q;

	if (quotient_f) {
	r = (r % d) << 8;
	q = (q << 8) \| (r / d);
	r = (r % d) << 8;
	*quotient_f = (q << 8) \| (r / d);
	}
	}

	static void sp887x_correct_offsets (struct sp887x_state* state,
	struct dtv_frontend_properties *p,
	int actual_freq)
	{
	static const u32 srate_correction [] = { 1879617, 4544878, 8098561 };
	int bw_index;
	int freq_offset = actual_freq - p->frequency;
	int sysclock = 61003; //[kHz]
	int ifreq = 36000000;
	int freq;
	int frequency_shift;

	switch (p->bandwidth_hz) {
	default:
	case 8000000:
	bw_index = 0;
	break;
	case 7000000:
	bw_index = 1;
	break;
	case 6000000:
	bw_index = 2;
	break;
	}

	if (p->inversion == INVERSION_ON)
	freq = ifreq - freq_offset;
	else
	freq = ifreq + freq_offset;

	divide(freq / 333, sysclock, NULL, &frequency_shift);

	if (p->inversion == INVERSION_ON)
	frequency_shift = -frequency_shift;

	/* sample rate correction */
	sp887x_writereg(state, 0x319, srate_correction[bw_index] >> 12);
	sp887x_writereg(state, 0x31a, srate_correction[bw_index] & 0xfff);

	/* carrier offset correction */
	sp887x_writereg(state, 0x309, frequency_shift >> 12);
	sp887x_writereg(state, 0x30a, frequency_shift & 0xfff);
	}

	static int sp887x_setup_frontend_parameters(struct dvb_frontend *fe)
	{
	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
	struct sp887x_state* state = fe->demodulator_priv;
	unsigned actual_freq;
	int err;
	u16 val, reg0xc05;

	if (p->bandwidth_hz != 8000000 &&
	p->bandwidth_hz != 7000000 &&
	p->bandwidth_hz != 6000000)
	return -EINVAL;

	if ((err = configure_reg0xc05(p, &reg0xc05)))
	return err;

	sp887x_microcontroller_stop(state);

	/* setup the PLL */
	if (fe->ops.tuner_ops.set_params) {
	fe->ops.tuner_ops.set_params(fe);
	if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
	}
	if (fe->ops.tuner_ops.get_frequency) {
	fe->ops.tuner_ops.get_frequency(fe, &actual_freq);
	if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
	} else {
	actual_freq = p->frequency;
	}

	/* read status reg in order to clear <pending irqs */
	sp887x_readreg(state, 0x200);

	sp887x_correct_offsets(state, p, actual_freq);

	/* filter for 6/7/8 Mhz channel */
	if (p->bandwidth_hz == 6000000)
	val = 2;
	else if (p->bandwidth_hz == 7000000)
	val = 1;
	else
	val = 0;

	sp887x_writereg(state, 0x311, val);

	/* scan order: 2k first = 0, 8k first = 1 */
	if (p->transmission_mode == TRANSMISSION_MODE_2K)
	sp887x_writereg(state, 0x338, 0x000);
	else
	sp887x_writereg(state, 0x338, 0x001);

	sp887x_writereg(state, 0xc05, reg0xc05);

	if (p->bandwidth_hz == 6000000)
	val = 2 << 3;
	else if (p->bandwidth_hz == 7000000)
	val = 3 << 3;
	else
	val = 0 << 3;

	/* enable OFDM and SAW bits as lock indicators in sync register 0xf17,
	* optimize algorithm for given bandwidth...
	*/
	sp887x_writereg(state, 0xf14, 0x160 \| val);
	sp887x_writereg(state, 0xf15, 0x000);

	sp887x_microcontroller_start(state);
	return 0;
	}

	static int sp887x_read_status(struct dvb_frontend fe, enum fe_status status)
	{
	struct sp887x_state* state = fe->demodulator_priv;
	u16 snr12 = sp887x_readreg(state, 0xf16);
	u16 sync0x200 = sp887x_readreg(state, 0x200);
	u16 sync0xf17 = sp887x_readreg(state, 0xf17);

	*status = 0;

	if (snr12 > 0x00f)
	*status \|= FE_HAS_SIGNAL;

	//if (sync0x200 & 0x004)
	// *status \|= FE_HAS_SYNC \| FE_HAS_CARRIER;

	//if (sync0x200 & 0x008)
	// *status \|= FE_HAS_VITERBI;

	if ((sync0xf17 & 0x00f) == 0x002) {
	*status \|= FE_HAS_LOCK;
	*status \|= FE_HAS_VITERBI \| FE_HAS_SYNC \| FE_HAS_CARRIER;
	}

	if (sync0x200 & 0x001) { /* tuner adjustment requested...*/
	int steps = (sync0x200 >> 4) & 0x00f;
	if (steps & 0x008)
	steps = -steps;
	dprintk("sp887x: implement tuner adjustment (%+i steps)!!\n",
	steps);
	}

	return 0;
	}

	static int sp887x_read_ber(struct dvb_frontend* fe, u32* ber)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	*ber = (sp887x_readreg(state, 0xc08) & 0x3f) \|
	(sp887x_readreg(state, 0xc07) << 6);
	sp887x_writereg(state, 0xc08, 0x000);
	sp887x_writereg(state, 0xc07, 0x000);
	if (*ber >= 0x3fff0)
	*ber = ~0;

	return 0;
	}

	static int sp887x_read_signal_strength(struct dvb_frontend* fe, u16* strength)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	u16 snr12 = sp887x_readreg(state, 0xf16);
	u32 signal = 3 * (snr12 << 4);
	*strength = (signal < 0xffff) ? signal : 0xffff;

	return 0;
	}

	static int sp887x_read_snr(struct dvb_frontend* fe, u16* snr)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	u16 snr12 = sp887x_readreg(state, 0xf16);
	*snr = (snr12 << 4) \| (snr12 >> 8);

	return 0;
	}

	static int sp887x_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	*ucblocks = sp887x_readreg(state, 0xc0c);
	if (*ucblocks == 0xfff)
	*ucblocks = ~0;

	return 0;
	}

	static int sp887x_i2c_gate_ctrl(struct dvb_frontend* fe, int enable)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	if (enable) {
	return sp887x_writereg(state, 0x206, 0x001);
	} else {
	return sp887x_writereg(state, 0x206, 0x000);
	}
	}

	static int sp887x_sleep(struct dvb_frontend* fe)
	{
	struct sp887x_state* state = fe->demodulator_priv;

	/* tristate TS output and disable interface pins */
	sp887x_writereg(state, 0xc18, 0x000);

	return 0;
	}

	static int sp887x_init(struct dvb_frontend* fe)
	{
	struct sp887x_state* state = fe->demodulator_priv;
	const struct firmware *fw = NULL;
	int ret;

	if (!state->initialised) {
	/* request the firmware, this will block until someone uploads it */
	printk("sp887x: waiting for firmware upload (%s)...\n", SP887X_DEFAULT_FIRMWARE);
	ret = state->config->request_firmware(fe, &fw, SP887X_DEFAULT_FIRMWARE);
	if (ret) {
	printk("sp887x: no firmware upload (timeout or file not found?)\n");
	return ret;
	}

	ret = sp887x_initial_setup(fe, fw);
	release_firmware(fw);
	if (ret) {
	printk("sp887x: writing firmware to device failed\n");
	return ret;
	}
	printk("sp887x: firmware upload complete\n");
	state->initialised = 1;
	}

	/* enable TS output and interface pins */
	sp887x_writereg(state, 0xc18, 0x00d);

	return 0;
	}

	static int sp887x_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fesettings)
	{
	fesettings->min_delay_ms = 350;
	fesettings->step_size = 166666*2;
	fesettings->max_drift = (166666*2)+1;
	return 0;
	}

	static void sp887x_release(struct dvb_frontend* fe)
	{
	struct sp887x_state* state = fe->demodulator_priv;
	kfree(state);
	}

	static const struct dvb_frontend_ops sp887x_ops;

	struct dvb_frontend* sp887x_attach(const struct sp887x_config* config,
	struct i2c_adapter* i2c)
	{
	struct sp887x_state* state = NULL;

	/* allocate memory for the internal state */
	state = kzalloc(sizeof(struct sp887x_state), GFP_KERNEL);
	if (state == NULL) goto error;

	/* setup the state */
	state->config = config;
	state->i2c = i2c;
	state->initialised = 0;

	/* check if the demod is there */
	if (sp887x_readreg(state, 0x0200) < 0) goto error;

	/* create dvb_frontend */
	memcpy(&state->frontend.ops, &sp887x_ops, sizeof(struct dvb_frontend_ops));
	state->frontend.demodulator_priv = state;
	return &state->frontend;

	error:
	kfree(state);
	return NULL;
	}

	static const struct dvb_frontend_ops sp887x_ops = {
	.delsys = { SYS_DVBT },
	.info = {
	.name = "Spase SP887x DVB-T",
	.frequency_min_hz = 50500 * kHz,
	.frequency_max_hz = 858000 * kHz,
	.frequency_stepsize_hz = 166666,
	.caps = FE_CAN_FEC_1_2 \| FE_CAN_FEC_2_3 \| FE_CAN_FEC_3_4 \|
	FE_CAN_FEC_5_6 \| FE_CAN_FEC_7_8 \| FE_CAN_FEC_AUTO \|
	FE_CAN_QPSK \| FE_CAN_QAM_16 \| FE_CAN_QAM_64 \|
	FE_CAN_RECOVER
	},

	.release = sp887x_release,

	.init = sp887x_init,
	.sleep = sp887x_sleep,
	.i2c_gate_ctrl = sp887x_i2c_gate_ctrl,

	.set_frontend = sp887x_setup_frontend_parameters,
	.get_tune_settings = sp887x_get_tune_settings,

	.read_status = sp887x_read_status,
	.read_ber = sp887x_read_ber,
	.read_signal_strength = sp887x_read_signal_strength,
	.read_snr = sp887x_read_snr,
	.read_ucblocks = sp887x_read_ucblocks,
	};

	module_param(debug, int, 0644);
	MODULE_PARM_DESC(debug, "Turn on/off frontend debugging (default:off).");

	MODULE_DESCRIPTION("Spase sp887x DVB-T demodulator driver");
	MODULE_LICENSE("GPL");

	EXPORT_SYMBOL(sp887x_attach);