1 /*
2  *    Support for LGDT3302 and LGDT3303 - VSB/QAM
3  *
4  *    Copyright (C) 2005 Wilson Michaels <wilsonmichaels@earthlink.net>
5  *
6  *    This program is free software; you can redistribute it and/or modify
7  *    it under the terms of the GNU General Public License as published by
8  *    the Free Software Foundation; either version 2 of the License, or
9  *    (at your option) any later version.
10  *
11  *    This program is distributed in the hope that it will be useful,
12  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *    GNU General Public License for more details.
15  *
16  *    You should have received a copy of the GNU General Public License
17  *    along with this program; if not, write to the Free Software
18  *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19  *
20  */
21 
22 /*
23  *                      NOTES ABOUT THIS DRIVER
24  *
25  * This Linux driver supports:
26  *   DViCO FusionHDTV 3 Gold-Q
27  *   DViCO FusionHDTV 3 Gold-T
28  *   DViCO FusionHDTV 5 Gold
29  *   DViCO FusionHDTV 5 Lite
30  *   DViCO FusionHDTV 5 USB Gold
31  *   Air2PC/AirStar 2 ATSC 3rd generation (HD5000)
32  *   pcHDTV HD5500
33  *
34  */
35 
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/init.h>
39 #include <linux/delay.h>
40 #include <linux/string.h>
41 #include <linux/slab.h>
42 #include <asm/byteorder.h>
43 
44 #include "dvb_frontend.h"
45 #include "dvb_math.h"
46 #include "lgdt330x_priv.h"
47 #include "lgdt330x.h"
48 
49 /* Use Equalizer Mean Squared Error instead of Phaser Tracker MSE */
50 /* #define USE_EQMSE */
51 
52 static int debug;
53 module_param(debug, int, 0644);
54 MODULE_PARM_DESC(debug,"Turn on/off lgdt330x frontend debugging (default:off).");
55 #define dprintk(args...) \
56 do { \
57 if (debug) printk(KERN_DEBUG "lgdt330x: " args); \
58 } while (0)
59 
60 struct lgdt330x_state
61 {
62 	struct i2c_adapter* i2c;
63 
64 	/* Configuration settings */
65 	const struct lgdt330x_config* config;
66 
67 	struct dvb_frontend frontend;
68 
69 	/* Demodulator private data */
70 	fe_modulation_t current_modulation;
71 	u32 snr; /* Result of last SNR calculation */
72 
73 	/* Tuner private data */
74 	u32 current_frequency;
75 };
76 
77 static int i2c_write_demod_bytes (struct lgdt330x_state* state,
78 				  u8 *buf, /* data bytes to send */
79 				  int len  /* number of bytes to send */ )
80 {
81 	struct i2c_msg msg =
82 		{ .addr = state->config->demod_address,
83 		  .flags = 0,
84 		  .buf = buf,
85 		  .len = 2 };
86 	int i;
87 	int err;
88 
89 	for (i=0; i<len-1; i+=2){
90 		if ((err = i2c_transfer(state->i2c, &msg, 1)) != 1) {
91 			printk(KERN_WARNING "lgdt330x: %s error (addr %02x <- %02x, err = %i)\n", __func__, msg.buf[0], msg.buf[1], err);
92 			if (err < 0)
93 				return err;
94 			else
95 				return -EREMOTEIO;
96 		}
97 		msg.buf += 2;
98 	}
99 	return 0;
100 }
101 
102 /*
103  * This routine writes the register (reg) to the demod bus
104  * then reads the data returned for (len) bytes.
105  */
106 
107 static int i2c_read_demod_bytes(struct lgdt330x_state *state,
108 				enum I2C_REG reg, u8 *buf, int len)
109 {
110 	u8 wr [] = { reg };
111 	struct i2c_msg msg [] = {
112 		{ .addr = state->config->demod_address,
113 		  .flags = 0, .buf = wr,  .len = 1 },
114 		{ .addr = state->config->demod_address,
115 		  .flags = I2C_M_RD, .buf = buf, .len = len },
116 	};
117 	int ret;
118 	ret = i2c_transfer(state->i2c, msg, 2);
119 	if (ret != 2) {
120 		printk(KERN_WARNING "lgdt330x: %s: addr 0x%02x select 0x%02x error (ret == %i)\n", __func__, state->config->demod_address, reg, ret);
121 		if (ret >= 0)
122 			ret = -EIO;
123 	} else {
124 		ret = 0;
125 	}
126 	return ret;
127 }
128 
129 /* Software reset */
130 static int lgdt3302_SwReset(struct lgdt330x_state* state)
131 {
132 	u8 ret;
133 	u8 reset[] = {
134 		IRQ_MASK,
135 		0x00 /* bit 6 is active low software reset
136 		      *	bits 5-0 are 1 to mask interrupts */
137 	};
138 
139 	ret = i2c_write_demod_bytes(state,
140 				    reset, sizeof(reset));
141 	if (ret == 0) {
142 
143 		/* force reset high (inactive) and unmask interrupts */
144 		reset[1] = 0x7f;
145 		ret = i2c_write_demod_bytes(state,
146 					    reset, sizeof(reset));
147 	}
148 	return ret;
149 }
150 
151 static int lgdt3303_SwReset(struct lgdt330x_state* state)
152 {
153 	u8 ret;
154 	u8 reset[] = {
155 		0x02,
156 		0x00 /* bit 0 is active low software reset */
157 	};
158 
159 	ret = i2c_write_demod_bytes(state,
160 				    reset, sizeof(reset));
161 	if (ret == 0) {
162 
163 		/* force reset high (inactive) */
164 		reset[1] = 0x01;
165 		ret = i2c_write_demod_bytes(state,
166 					    reset, sizeof(reset));
167 	}
168 	return ret;
169 }
170 
171 static int lgdt330x_SwReset(struct lgdt330x_state* state)
172 {
173 	switch (state->config->demod_chip) {
174 	case LGDT3302:
175 		return lgdt3302_SwReset(state);
176 	case LGDT3303:
177 		return lgdt3303_SwReset(state);
178 	default:
179 		return -ENODEV;
180 	}
181 }
182 
183 static int lgdt330x_init(struct dvb_frontend* fe)
184 {
185 	/* Hardware reset is done using gpio[0] of cx23880x chip.
186 	 * I'd like to do it here, but don't know how to find chip address.
187 	 * cx88-cards.c arranges for the reset bit to be inactive (high).
188 	 * Maybe there needs to be a callable function in cx88-core or
189 	 * the caller of this function needs to do it. */
190 
191 	/*
192 	 * Array of byte pairs <address, value>
193 	 * to initialize each different chip
194 	 */
195 	static u8 lgdt3302_init_data[] = {
196 		/* Use 50MHz parameter values from spec sheet since xtal is 50 */
197 		/* Change the value of NCOCTFV[25:0] of carrier
198 		   recovery center frequency register */
199 		VSB_CARRIER_FREQ0, 0x00,
200 		VSB_CARRIER_FREQ1, 0x87,
201 		VSB_CARRIER_FREQ2, 0x8e,
202 		VSB_CARRIER_FREQ3, 0x01,
203 		/* Change the TPCLK pin polarity
204 		   data is valid on falling clock */
205 		DEMUX_CONTROL, 0xfb,
206 		/* Change the value of IFBW[11:0] of
207 		   AGC IF/RF loop filter bandwidth register */
208 		AGC_RF_BANDWIDTH0, 0x40,
209 		AGC_RF_BANDWIDTH1, 0x93,
210 		AGC_RF_BANDWIDTH2, 0x00,
211 		/* Change the value of bit 6, 'nINAGCBY' and
212 		   'NSSEL[1:0] of ACG function control register 2 */
213 		AGC_FUNC_CTRL2, 0xc6,
214 		/* Change the value of bit 6 'RFFIX'
215 		   of AGC function control register 3 */
216 		AGC_FUNC_CTRL3, 0x40,
217 		/* Set the value of 'INLVTHD' register 0x2a/0x2c
218 		   to 0x7fe */
219 		AGC_DELAY0, 0x07,
220 		AGC_DELAY2, 0xfe,
221 		/* Change the value of IAGCBW[15:8]
222 		   of inner AGC loop filter bandwidth */
223 		AGC_LOOP_BANDWIDTH0, 0x08,
224 		AGC_LOOP_BANDWIDTH1, 0x9a
225 	};
226 
227 	static u8 lgdt3303_init_data[] = {
228 		0x4c, 0x14
229 	};
230 
231 	static u8 flip_1_lgdt3303_init_data[] = {
232 		0x4c, 0x14,
233 		0x87, 0xf3
234 	};
235 
236 	static u8 flip_2_lgdt3303_init_data[] = {
237 		0x4c, 0x14,
238 		0x87, 0xda
239 	};
240 
241 	struct lgdt330x_state* state = fe->demodulator_priv;
242 	char  *chip_name;
243 	int    err;
244 
245 	switch (state->config->demod_chip) {
246 	case LGDT3302:
247 		chip_name = "LGDT3302";
248 		err = i2c_write_demod_bytes(state, lgdt3302_init_data,
249 					    sizeof(lgdt3302_init_data));
250 		break;
251 	case LGDT3303:
252 		chip_name = "LGDT3303";
253 		switch (state->config->clock_polarity_flip) {
254 		case 2:
255 			err = i2c_write_demod_bytes(state,
256 					flip_2_lgdt3303_init_data,
257 					sizeof(flip_2_lgdt3303_init_data));
258 			break;
259 		case 1:
260 			err = i2c_write_demod_bytes(state,
261 					flip_1_lgdt3303_init_data,
262 					sizeof(flip_1_lgdt3303_init_data));
263 			break;
264 		case 0:
265 		default:
266 			err = i2c_write_demod_bytes(state, lgdt3303_init_data,
267 						    sizeof(lgdt3303_init_data));
268 		}
269 		break;
270 	default:
271 		chip_name = "undefined";
272 		printk (KERN_WARNING "Only LGDT3302 and LGDT3303 are supported chips.\n");
273 		err = -ENODEV;
274 	}
275 	dprintk("%s entered as %s\n", __func__, chip_name);
276 	if (err < 0)
277 		return err;
278 	return lgdt330x_SwReset(state);
279 }
280 
281 static int lgdt330x_read_ber(struct dvb_frontend* fe, u32* ber)
282 {
283 	*ber = 0; /* Not supplied by the demod chips */
284 	return 0;
285 }
286 
287 static int lgdt330x_read_ucblocks(struct dvb_frontend* fe, u32* ucblocks)
288 {
289 	struct lgdt330x_state* state = fe->demodulator_priv;
290 	int err;
291 	u8 buf[2];
292 
293 	*ucblocks = 0;
294 
295 	switch (state->config->demod_chip) {
296 	case LGDT3302:
297 		err = i2c_read_demod_bytes(state, LGDT3302_PACKET_ERR_COUNTER1,
298 					   buf, sizeof(buf));
299 		break;
300 	case LGDT3303:
301 		err = i2c_read_demod_bytes(state, LGDT3303_PACKET_ERR_COUNTER1,
302 					   buf, sizeof(buf));
303 		break;
304 	default:
305 		printk(KERN_WARNING
306 		       "Only LGDT3302 and LGDT3303 are supported chips.\n");
307 		err = -ENODEV;
308 	}
309 	if (err < 0)
310 		return err;
311 
312 	*ucblocks = (buf[0] << 8) | buf[1];
313 	return 0;
314 }
315 
316 static int lgdt330x_set_parameters(struct dvb_frontend *fe)
317 {
318 	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
319 	/*
320 	 * Array of byte pairs <address, value>
321 	 * to initialize 8VSB for lgdt3303 chip 50 MHz IF
322 	 */
323 	static u8 lgdt3303_8vsb_44_data[] = {
324 		0x04, 0x00,
325 		0x0d, 0x40,
326 		0x0e, 0x87,
327 		0x0f, 0x8e,
328 		0x10, 0x01,
329 		0x47, 0x8b };
330 
331 	/*
332 	 * Array of byte pairs <address, value>
333 	 * to initialize QAM for lgdt3303 chip
334 	 */
335 	static u8 lgdt3303_qam_data[] = {
336 		0x04, 0x00,
337 		0x0d, 0x00,
338 		0x0e, 0x00,
339 		0x0f, 0x00,
340 		0x10, 0x00,
341 		0x51, 0x63,
342 		0x47, 0x66,
343 		0x48, 0x66,
344 		0x4d, 0x1a,
345 		0x49, 0x08,
346 		0x4a, 0x9b };
347 
348 	struct lgdt330x_state* state = fe->demodulator_priv;
349 
350 	static u8 top_ctrl_cfg[]   = { TOP_CONTROL, 0x03 };
351 
352 	int err = 0;
353 	/* Change only if we are actually changing the modulation */
354 	if (state->current_modulation != p->modulation) {
355 		switch (p->modulation) {
356 		case VSB_8:
357 			dprintk("%s: VSB_8 MODE\n", __func__);
358 
359 			/* Select VSB mode */
360 			top_ctrl_cfg[1] = 0x03;
361 
362 			/* Select ANT connector if supported by card */
363 			if (state->config->pll_rf_set)
364 				state->config->pll_rf_set(fe, 1);
365 
366 			if (state->config->demod_chip == LGDT3303) {
367 				err = i2c_write_demod_bytes(state, lgdt3303_8vsb_44_data,
368 							    sizeof(lgdt3303_8vsb_44_data));
369 			}
370 			break;
371 
372 		case QAM_64:
373 			dprintk("%s: QAM_64 MODE\n", __func__);
374 
375 			/* Select QAM_64 mode */
376 			top_ctrl_cfg[1] = 0x00;
377 
378 			/* Select CABLE connector if supported by card */
379 			if (state->config->pll_rf_set)
380 				state->config->pll_rf_set(fe, 0);
381 
382 			if (state->config->demod_chip == LGDT3303) {
383 				err = i2c_write_demod_bytes(state, lgdt3303_qam_data,
384 											sizeof(lgdt3303_qam_data));
385 			}
386 			break;
387 
388 		case QAM_256:
389 			dprintk("%s: QAM_256 MODE\n", __func__);
390 
391 			/* Select QAM_256 mode */
392 			top_ctrl_cfg[1] = 0x01;
393 
394 			/* Select CABLE connector if supported by card */
395 			if (state->config->pll_rf_set)
396 				state->config->pll_rf_set(fe, 0);
397 
398 			if (state->config->demod_chip == LGDT3303) {
399 				err = i2c_write_demod_bytes(state, lgdt3303_qam_data,
400 											sizeof(lgdt3303_qam_data));
401 			}
402 			break;
403 		default:
404 			printk(KERN_WARNING "lgdt330x: %s: Modulation type(%d) UNSUPPORTED\n", __func__, p->modulation);
405 			return -1;
406 		}
407 		if (err < 0)
408 			printk(KERN_WARNING "lgdt330x: %s: error blasting "
409 			       "bytes to lgdt3303 for modulation type(%d)\n",
410 			       __func__, p->modulation);
411 
412 		/*
413 		 * select serial or parallel MPEG harware interface
414 		 * Serial:   0x04 for LGDT3302 or 0x40 for LGDT3303
415 		 * Parallel: 0x00
416 		 */
417 		top_ctrl_cfg[1] |= state->config->serial_mpeg;
418 
419 		/* Select the requested mode */
420 		i2c_write_demod_bytes(state, top_ctrl_cfg,
421 				      sizeof(top_ctrl_cfg));
422 		if (state->config->set_ts_params)
423 			state->config->set_ts_params(fe, 0);
424 		state->current_modulation = p->modulation;
425 	}
426 
427 	/* Tune to the specified frequency */
428 	if (fe->ops.tuner_ops.set_params) {
429 		fe->ops.tuner_ops.set_params(fe);
430 		if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
431 	}
432 
433 	/* Keep track of the new frequency */
434 	/* FIXME this is the wrong way to do this...           */
435 	/* The tuner is shared with the video4linux analog API */
436 	state->current_frequency = p->frequency;
437 
438 	lgdt330x_SwReset(state);
439 	return 0;
440 }
441 
442 static int lgdt330x_get_frontend(struct dvb_frontend *fe)
443 {
444 	struct dtv_frontend_properties *p = &fe->dtv_property_cache;
445 	struct lgdt330x_state *state = fe->demodulator_priv;
446 	p->frequency = state->current_frequency;
447 	return 0;
448 }
449 
450 static int lgdt3302_read_status(struct dvb_frontend* fe, fe_status_t* status)
451 {
452 	struct lgdt330x_state* state = fe->demodulator_priv;
453 	u8 buf[3];
454 
455 	*status = 0; /* Reset status result */
456 
457 	/* AGC status register */
458 	i2c_read_demod_bytes(state, AGC_STATUS, buf, 1);
459 	dprintk("%s: AGC_STATUS = 0x%02x\n", __func__, buf[0]);
460 	if ((buf[0] & 0x0c) == 0x8){
461 		/* Test signal does not exist flag */
462 		/* as well as the AGC lock flag.   */
463 		*status |= FE_HAS_SIGNAL;
464 	}
465 
466 	/*
467 	 * You must set the Mask bits to 1 in the IRQ_MASK in order
468 	 * to see that status bit in the IRQ_STATUS register.
469 	 * This is done in SwReset();
470 	 */
471 	/* signal status */
472 	i2c_read_demod_bytes(state, TOP_CONTROL, buf, sizeof(buf));
473 	dprintk("%s: TOP_CONTROL = 0x%02x, IRO_MASK = 0x%02x, IRQ_STATUS = 0x%02x\n", __func__, buf[0], buf[1], buf[2]);
474 
475 
476 	/* sync status */
477 	if ((buf[2] & 0x03) == 0x01) {
478 		*status |= FE_HAS_SYNC;
479 	}
480 
481 	/* FEC error status */
482 	if ((buf[2] & 0x0c) == 0x08) {
483 		*status |= FE_HAS_LOCK;
484 		*status |= FE_HAS_VITERBI;
485 	}
486 
487 	/* Carrier Recovery Lock Status Register */
488 	i2c_read_demod_bytes(state, CARRIER_LOCK, buf, 1);
489 	dprintk("%s: CARRIER_LOCK = 0x%02x\n", __func__, buf[0]);
490 	switch (state->current_modulation) {
491 	case QAM_256:
492 	case QAM_64:
493 		/* Need to understand why there are 3 lock levels here */
494 		if ((buf[0] & 0x07) == 0x07)
495 			*status |= FE_HAS_CARRIER;
496 		break;
497 	case VSB_8:
498 		if ((buf[0] & 0x80) == 0x80)
499 			*status |= FE_HAS_CARRIER;
500 		break;
501 	default:
502 		printk(KERN_WARNING "lgdt330x: %s: Modulation set to unsupported value\n", __func__);
503 	}
504 
505 	return 0;
506 }
507 
508 static int lgdt3303_read_status(struct dvb_frontend* fe, fe_status_t* status)
509 {
510 	struct lgdt330x_state* state = fe->demodulator_priv;
511 	int err;
512 	u8 buf[3];
513 
514 	*status = 0; /* Reset status result */
515 
516 	/* lgdt3303 AGC status register */
517 	err = i2c_read_demod_bytes(state, 0x58, buf, 1);
518 	if (err < 0)
519 		return err;
520 
521 	dprintk("%s: AGC_STATUS = 0x%02x\n", __func__, buf[0]);
522 	if ((buf[0] & 0x21) == 0x01){
523 		/* Test input signal does not exist flag */
524 		/* as well as the AGC lock flag.   */
525 		*status |= FE_HAS_SIGNAL;
526 	}
527 
528 	/* Carrier Recovery Lock Status Register */
529 	i2c_read_demod_bytes(state, CARRIER_LOCK, buf, 1);
530 	dprintk("%s: CARRIER_LOCK = 0x%02x\n", __func__, buf[0]);
531 	switch (state->current_modulation) {
532 	case QAM_256:
533 	case QAM_64:
534 		/* Need to understand why there are 3 lock levels here */
535 		if ((buf[0] & 0x07) == 0x07)
536 			*status |= FE_HAS_CARRIER;
537 		else
538 			break;
539 		i2c_read_demod_bytes(state, 0x8a, buf, 1);
540 		if ((buf[0] & 0x04) == 0x04)
541 			*status |= FE_HAS_SYNC;
542 		if ((buf[0] & 0x01) == 0x01)
543 			*status |= FE_HAS_LOCK;
544 		if ((buf[0] & 0x08) == 0x08)
545 			*status |= FE_HAS_VITERBI;
546 		break;
547 	case VSB_8:
548 		if ((buf[0] & 0x80) == 0x80)
549 			*status |= FE_HAS_CARRIER;
550 		else
551 			break;
552 		i2c_read_demod_bytes(state, 0x38, buf, 1);
553 		if ((buf[0] & 0x02) == 0x00)
554 			*status |= FE_HAS_SYNC;
555 		if ((buf[0] & 0x01) == 0x01) {
556 			*status |= FE_HAS_LOCK;
557 			*status |= FE_HAS_VITERBI;
558 		}
559 		break;
560 	default:
561 		printk(KERN_WARNING "lgdt330x: %s: Modulation set to unsupported value\n", __func__);
562 	}
563 	return 0;
564 }
565 
566 /* Calculate SNR estimation (scaled by 2^24)
567 
568    8-VSB SNR equations from LGDT3302 and LGDT3303 datasheets, QAM
569    equations from LGDT3303 datasheet.  VSB is the same between the '02
570    and '03, so maybe QAM is too?  Perhaps someone with a newer datasheet
571    that has QAM information could verify?
572 
573    For 8-VSB: (two ways, take your pick)
574    LGDT3302:
575      SNR_EQ = 10 * log10(25 * 24^2 / EQ_MSE)
576    LGDT3303:
577      SNR_EQ = 10 * log10(25 * 32^2 / EQ_MSE)
578    LGDT3302 & LGDT3303:
579      SNR_PT = 10 * log10(25 * 32^2 / PT_MSE)  (we use this one)
580    For 64-QAM:
581      SNR    = 10 * log10( 688128   / MSEQAM)
582    For 256-QAM:
583      SNR    = 10 * log10( 696320   / MSEQAM)
584 
585    We re-write the snr equation as:
586      SNR * 2^24 = 10*(c - intlog10(MSE))
587    Where for 256-QAM, c = log10(696320) * 2^24, and so on. */
588 
589 static u32 calculate_snr(u32 mse, u32 c)
590 {
591 	if (mse == 0) /* No signal */
592 		return 0;
593 
594 	mse = intlog10(mse);
595 	if (mse > c) {
596 		/* Negative SNR, which is possible, but realisticly the
597 		demod will lose lock before the signal gets this bad.  The
598 		API only allows for unsigned values, so just return 0 */
599 		return 0;
600 	}
601 	return 10*(c - mse);
602 }
603 
604 static int lgdt3302_read_snr(struct dvb_frontend* fe, u16* snr)
605 {
606 	struct lgdt330x_state* state = (struct lgdt330x_state*) fe->demodulator_priv;
607 	u8 buf[5];	/* read data buffer */
608 	u32 noise;	/* noise value */
609 	u32 c;		/* per-modulation SNR calculation constant */
610 
611 	switch(state->current_modulation) {
612 	case VSB_8:
613 		i2c_read_demod_bytes(state, LGDT3302_EQPH_ERR0, buf, 5);
614 #ifdef USE_EQMSE
615 		/* Use Equalizer Mean-Square Error Register */
616 		/* SNR for ranges from -15.61 to +41.58 */
617 		noise = ((buf[0] & 7) << 16) | (buf[1] << 8) | buf[2];
618 		c = 69765745; /* log10(25*24^2)*2^24 */
619 #else
620 		/* Use Phase Tracker Mean-Square Error Register */
621 		/* SNR for ranges from -13.11 to +44.08 */
622 		noise = ((buf[0] & 7<<3) << 13) | (buf[3] << 8) | buf[4];
623 		c = 73957994; /* log10(25*32^2)*2^24 */
624 #endif
625 		break;
626 	case QAM_64:
627 	case QAM_256:
628 		i2c_read_demod_bytes(state, CARRIER_MSEQAM1, buf, 2);
629 		noise = ((buf[0] & 3) << 8) | buf[1];
630 		c = state->current_modulation == QAM_64 ? 97939837 : 98026066;
631 		/* log10(688128)*2^24 and log10(696320)*2^24 */
632 		break;
633 	default:
634 		printk(KERN_ERR "lgdt330x: %s: Modulation set to unsupported value\n",
635 		       __func__);
636 		return -EREMOTEIO; /* return -EDRIVER_IS_GIBBERED; */
637 	}
638 
639 	state->snr = calculate_snr(noise, c);
640 	*snr = (state->snr) >> 16; /* Convert from 8.24 fixed-point to 8.8 */
641 
642 	dprintk("%s: noise = 0x%08x, snr = %d.%02d dB\n", __func__, noise,
643 		state->snr >> 24, (((state->snr>>8) & 0xffff) * 100) >> 16);
644 
645 	return 0;
646 }
647 
648 static int lgdt3303_read_snr(struct dvb_frontend* fe, u16* snr)
649 {
650 	struct lgdt330x_state* state = (struct lgdt330x_state*) fe->demodulator_priv;
651 	u8 buf[5];	/* read data buffer */
652 	u32 noise;	/* noise value */
653 	u32 c;		/* per-modulation SNR calculation constant */
654 
655 	switch(state->current_modulation) {
656 	case VSB_8:
657 		i2c_read_demod_bytes(state, LGDT3303_EQPH_ERR0, buf, 5);
658 #ifdef USE_EQMSE
659 		/* Use Equalizer Mean-Square Error Register */
660 		/* SNR for ranges from -16.12 to +44.08 */
661 		noise = ((buf[0] & 0x78) << 13) | (buf[1] << 8) | buf[2];
662 		c = 73957994; /* log10(25*32^2)*2^24 */
663 #else
664 		/* Use Phase Tracker Mean-Square Error Register */
665 		/* SNR for ranges from -13.11 to +44.08 */
666 		noise = ((buf[0] & 7) << 16) | (buf[3] << 8) | buf[4];
667 		c = 73957994; /* log10(25*32^2)*2^24 */
668 #endif
669 		break;
670 	case QAM_64:
671 	case QAM_256:
672 		i2c_read_demod_bytes(state, CARRIER_MSEQAM1, buf, 2);
673 		noise = (buf[0] << 8) | buf[1];
674 		c = state->current_modulation == QAM_64 ? 97939837 : 98026066;
675 		/* log10(688128)*2^24 and log10(696320)*2^24 */
676 		break;
677 	default:
678 		printk(KERN_ERR "lgdt330x: %s: Modulation set to unsupported value\n",
679 		       __func__);
680 		return -EREMOTEIO; /* return -EDRIVER_IS_GIBBERED; */
681 	}
682 
683 	state->snr = calculate_snr(noise, c);
684 	*snr = (state->snr) >> 16; /* Convert from 8.24 fixed-point to 8.8 */
685 
686 	dprintk("%s: noise = 0x%08x, snr = %d.%02d dB\n", __func__, noise,
687 		state->snr >> 24, (((state->snr >> 8) & 0xffff) * 100) >> 16);
688 
689 	return 0;
690 }
691 
692 static int lgdt330x_read_signal_strength(struct dvb_frontend* fe, u16* strength)
693 {
694 	/* Calculate Strength from SNR up to 35dB */
695 	/* Even though the SNR can go higher than 35dB, there is some comfort */
696 	/* factor in having a range of strong signals that can show at 100%   */
697 	struct lgdt330x_state* state = (struct lgdt330x_state*) fe->demodulator_priv;
698 	u16 snr;
699 	int ret;
700 
701 	ret = fe->ops.read_snr(fe, &snr);
702 	if (ret != 0)
703 		return ret;
704 	/* Rather than use the 8.8 value snr, use state->snr which is 8.24 */
705 	/* scale the range 0 - 35*2^24 into 0 - 65535 */
706 	if (state->snr >= 8960 * 0x10000)
707 		*strength = 0xffff;
708 	else
709 		*strength = state->snr / 8960;
710 
711 	return 0;
712 }
713 
714 static int lgdt330x_get_tune_settings(struct dvb_frontend* fe, struct dvb_frontend_tune_settings* fe_tune_settings)
715 {
716 	/* I have no idea about this - it may not be needed */
717 	fe_tune_settings->min_delay_ms = 500;
718 	fe_tune_settings->step_size = 0;
719 	fe_tune_settings->max_drift = 0;
720 	return 0;
721 }
722 
723 static void lgdt330x_release(struct dvb_frontend* fe)
724 {
725 	struct lgdt330x_state* state = (struct lgdt330x_state*) fe->demodulator_priv;
726 	kfree(state);
727 }
728 
729 static struct dvb_frontend_ops lgdt3302_ops;
730 static struct dvb_frontend_ops lgdt3303_ops;
731 
732 struct dvb_frontend* lgdt330x_attach(const struct lgdt330x_config* config,
733 				     struct i2c_adapter* i2c)
734 {
735 	struct lgdt330x_state* state = NULL;
736 	u8 buf[1];
737 
738 	/* Allocate memory for the internal state */
739 	state = kzalloc(sizeof(struct lgdt330x_state), GFP_KERNEL);
740 	if (state == NULL)
741 		goto error;
742 
743 	/* Setup the state */
744 	state->config = config;
745 	state->i2c = i2c;
746 
747 	/* Create dvb_frontend */
748 	switch (config->demod_chip) {
749 	case LGDT3302:
750 		memcpy(&state->frontend.ops, &lgdt3302_ops, sizeof(struct dvb_frontend_ops));
751 		break;
752 	case LGDT3303:
753 		memcpy(&state->frontend.ops, &lgdt3303_ops, sizeof(struct dvb_frontend_ops));
754 		break;
755 	default:
756 		goto error;
757 	}
758 	state->frontend.demodulator_priv = state;
759 
760 	/* Verify communication with demod chip */
761 	if (i2c_read_demod_bytes(state, 2, buf, 1))
762 		goto error;
763 
764 	state->current_frequency = -1;
765 	state->current_modulation = -1;
766 
767 	return &state->frontend;
768 
769 error:
770 	kfree(state);
771 	dprintk("%s: ERROR\n",__func__);
772 	return NULL;
773 }
774 
775 static struct dvb_frontend_ops lgdt3302_ops = {
776 	.delsys = { SYS_ATSC, SYS_DVBC_ANNEX_B },
777 	.info = {
778 		.name= "LG Electronics LGDT3302 VSB/QAM Frontend",
779 		.frequency_min= 54000000,
780 		.frequency_max= 858000000,
781 		.frequency_stepsize= 62500,
782 		.symbol_rate_min    = 5056941,	/* QAM 64 */
783 		.symbol_rate_max    = 10762000,	/* VSB 8  */
784 		.caps = FE_CAN_QAM_64 | FE_CAN_QAM_256 | FE_CAN_8VSB
785 	},
786 	.init                 = lgdt330x_init,
787 	.set_frontend         = lgdt330x_set_parameters,
788 	.get_frontend         = lgdt330x_get_frontend,
789 	.get_tune_settings    = lgdt330x_get_tune_settings,
790 	.read_status          = lgdt3302_read_status,
791 	.read_ber             = lgdt330x_read_ber,
792 	.read_signal_strength = lgdt330x_read_signal_strength,
793 	.read_snr             = lgdt3302_read_snr,
794 	.read_ucblocks        = lgdt330x_read_ucblocks,
795 	.release              = lgdt330x_release,
796 };
797 
798 static struct dvb_frontend_ops lgdt3303_ops = {
799 	.delsys = { SYS_ATSC, SYS_DVBC_ANNEX_B },
800 	.info = {
801 		.name= "LG Electronics LGDT3303 VSB/QAM Frontend",
802 		.frequency_min= 54000000,
803 		.frequency_max= 858000000,
804 		.frequency_stepsize= 62500,
805 		.symbol_rate_min    = 5056941,	/* QAM 64 */
806 		.symbol_rate_max    = 10762000,	/* VSB 8  */
807 		.caps = FE_CAN_QAM_64 | FE_CAN_QAM_256 | FE_CAN_8VSB
808 	},
809 	.init                 = lgdt330x_init,
810 	.set_frontend         = lgdt330x_set_parameters,
811 	.get_frontend         = lgdt330x_get_frontend,
812 	.get_tune_settings    = lgdt330x_get_tune_settings,
813 	.read_status          = lgdt3303_read_status,
814 	.read_ber             = lgdt330x_read_ber,
815 	.read_signal_strength = lgdt330x_read_signal_strength,
816 	.read_snr             = lgdt3303_read_snr,
817 	.read_ucblocks        = lgdt330x_read_ucblocks,
818 	.release              = lgdt330x_release,
819 };
820 
821 MODULE_DESCRIPTION("LGDT330X (ATSC 8VSB & ITU-T J.83 AnnexB 64/256 QAM) Demodulator Driver");
822 MODULE_AUTHOR("Wilson Michaels");
823 MODULE_LICENSE("GPL");
824 
825 EXPORT_SYMBOL(lgdt330x_attach);
826