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