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* [PATCH v2] Fix the derot zig-zag to work with TT-USB2.0 TechnoTrend
@ 2011-05-25  8:34 Hans Petter Selasky
  0 siblings, 0 replies; only message in thread
From: Hans Petter Selasky @ 2011-05-25  8:34 UTC (permalink / raw)
  To: linux-media

(The initial patch cause too long tune delay on non-present carriers. Use the 
hardware derot, by writing zero to the derot register.)

>From 2b960abaeeaa32f6bcaa350ca80906c467ab9cb1 Mon Sep 17 00:00:00 2001
From: Hans Petter Selasky <hselasky@c2i.net>
Date: Tue, 24 May 2011 21:44:53 +0200
Subject: [PATCH] Fix the derot zig-zag to work with TT-USB2.0 TechnoTrend 
hardware.

Signed-off-by: Hans Petter Selasky <hselasky@c2i.net>
---
 drivers/media/dvb/frontends/stb0899_algo.c |  130 
++++++++--------------------
 drivers/media/dvb/frontends/stb0899_priv.h |    2 -
 2 files changed, 36 insertions(+), 96 deletions(-)

diff --git a/drivers/media/dvb/frontends/stb0899_algo.c 
b/drivers/media/dvb/frontends/stb0899_algo.c
index d70eee0..0cdaac2 100644
--- a/drivers/media/dvb/frontends/stb0899_algo.c
+++ b/drivers/media/dvb/frontends/stb0899_algo.c
@@ -117,7 +117,7 @@ static u32 stb0899_set_srate(struct stb0899_state *state, 
u32 master_clk, u32 sr
  */
 static long stb0899_calc_derot_time(long srate)
 {
-	if (srate > 0)
+	if (srate > 999)
 		return (100000 / (srate / 1000));
 	else
 		return 0;
@@ -207,36 +207,23 @@ static enum stb0899_status stb0899_search_tmg(struct 
stb0899_state *state)
 {
 	struct stb0899_internal *internal = &state->internal;
 	struct stb0899_params *params = &state->params;
-
-	short int derot_step, derot_freq = 0, derot_limit, next_loop = 3;
-	int index = 0;
-	u8 cfr[2];
+	int index;
+	u8 cfr[2] = {0,0};
 
 	internal->status = NOTIMING;
 
-	/* timing loop computation & symbol rate optimisation	*/
-	derot_limit = (internal->sub_range / 2L) / internal->mclk;
-	derot_step = (params->srate / 2L) / internal->mclk;
-
-	while ((stb0899_check_tmg(state) != TIMINGOK) && next_loop) {
-		index++;
-		derot_freq += index * internal->direction * derot_step;	/* next 
derot zig zag position	*/
+	/* let the hardware figure out derot frequency */
+	stb0899_write_regs(state, STB0899_CFRM, cfr, 2); /* derotator frequency		
*/
 
-		if (abs(derot_freq) > derot_limit)
-			next_loop--;
-
-		if (next_loop) {
-			STB0899_SETFIELD_VAL(CFRM, cfr[0], MSB(state->config->inversion * 
derot_freq));
-			STB0899_SETFIELD_VAL(CFRL, cfr[1], LSB(state->config->inversion * 
derot_freq));
-			stb0899_write_regs(state, STB0899_CFRM, cfr, 2); /* derotator 
frequency		*/
+	for (index = 0; index < 8; index++) {
+		if (stb0899_check_tmg(state) == TIMINGOK) {
+			/* get derotator frequency */
+			stb0899_read_regs(state, STB0899_CFRM, cfr, 2);
+			internal->derot_freq = state->config->inversion * 
MAKEWORD16(cfr[0], cfr[1]);
+			dprintk(state->verbose, FE_DEBUG, 1, "------->TIMING OK ! "
+			    "Derot Freq = %d", internal->derot_freq);
+			break;
 		}
-		internal->direction = -internal->direction;	/* Change zigzag direction	
	*/
-	}
-
-	if (internal->status == TIMINGOK) {
-		stb0899_read_regs(state, STB0899_CFRM, cfr, 2); /* get derotator 
frequency		*/
-		internal->derot_freq = state->config->inversion * MAKEWORD16(cfr[0], 
cfr[1]);
-		dprintk(state->verbose, FE_DEBUG, 1, "------->TIMING OK ! Derot Freq = 
%d", internal->derot_freq);
 	}
 
 	return internal->status;
@@ -277,50 +264,25 @@ static enum stb0899_status stb0899_check_carrier(struct 
stb0899_state *state)
 static enum stb0899_status stb0899_search_carrier(struct stb0899_state 
*state)
 {
 	struct stb0899_internal *internal = &state->internal;
-
-	short int derot_freq = 0, last_derot_freq = 0, derot_limit, next_loop = 3;
-	int index = 0;
+	int index;
 	u8 cfr[2];
 	u8 reg;
 
 	internal->status = NOCARRIER;
-	derot_limit = (internal->sub_range / 2L) / internal->mclk;
-	derot_freq = internal->derot_freq;
 
 	reg = stb0899_read_reg(state, STB0899_CFD);
 	STB0899_SETFIELD_VAL(CFD_ON, reg, 1);
 	stb0899_write_reg(state, STB0899_CFD, reg);
 
-	do {
-		dprintk(state->verbose, FE_DEBUG, 1, "Derot Freq=%d, mclk=%d", 
derot_freq, internal->mclk);
-		if (stb0899_check_carrier(state) == NOCARRIER) {
-			index++;
-			last_derot_freq = derot_freq;
-			derot_freq += index * internal->direction * internal->derot_step; 
/* next zig zag derotator position */
-
-			if(abs(derot_freq) > derot_limit)
-				next_loop--;
-
-			if (next_loop) {
-				reg = stb0899_read_reg(state, STB0899_CFD);
-				STB0899_SETFIELD_VAL(CFD_ON, reg, 1);
-				stb0899_write_reg(state, STB0899_CFD, reg);
-
-				STB0899_SETFIELD_VAL(CFRM, cfr[0], MSB(state->config-
>inversion * derot_freq));
-				STB0899_SETFIELD_VAL(CFRL, cfr[1], LSB(state->config-
>inversion * derot_freq));
-				stb0899_write_regs(state, STB0899_CFRM, cfr, 2); /* derotator 
frequency	*/
-			}
+	for (index = 0; index < 8; index++) {
+		if (stb0899_check_carrier(state) == CARRIEROK) {
+			/* get derotator frequency */
+			stb0899_read_regs(state, STB0899_CFRM, cfr, 2);
+			internal->derot_freq = state->config->inversion * 
MAKEWORD16(cfr[0], cfr[1]);
+			dprintk(state->verbose, FE_DEBUG, 1, "----> CARRIER OK !, "
+			    "Derot Freq=%d", internal->derot_freq);
+			break;
 		}
-
-		internal->direction = -internal->direction; /* Change zigzag direction 
*/
-	} while ((internal->status != CARRIEROK) && next_loop);
-
-	if (internal->status == CARRIEROK) {
-		stb0899_read_regs(state, STB0899_CFRM, cfr, 2); /* get derotator 
frequency */
-		internal->derot_freq = state->config->inversion * MAKEWORD16(cfr[0], 
cfr[1]);
-		dprintk(state->verbose, FE_DEBUG, 1, "----> CARRIER OK !, Derot 
Freq=%d", internal->derot_freq);
-	} else {
-		internal->derot_freq = last_derot_freq;
 	}
 
 	return internal->status;
@@ -384,46 +346,29 @@ static enum stb0899_status stb0899_check_data(struct 
stb0899_state *state)
  */
 static enum stb0899_status stb0899_search_data(struct stb0899_state *state)
 {
-	short int derot_freq, derot_step, derot_limit, next_loop = 3;
 	u8 cfr[2];
 	u8 reg;
-	int index = 1;
+	int index;
 
 	struct stb0899_internal *internal = &state->internal;
 	struct stb0899_params *params = &state->params;
 
-	derot_step = (params->srate / 4L) / internal->mclk;
-	derot_limit = (internal->sub_range / 2L) / internal->mclk;
-	derot_freq = internal->derot_freq;
-
-	do {
-		if ((internal->status != CARRIEROK) || (stb0899_check_data(state) != 
DATAOK)) {
-
-			derot_freq += index * internal->direction * derot_step;	/* next 
zig zag derotator position */
-			if (abs(derot_freq) > derot_limit)
-				next_loop--;
+	for (index = 0; index < 8; index++) {
 
-			if (next_loop) {
-				dprintk(state->verbose, FE_DEBUG, 1, "Derot freq=%d, mclk=%d", 
derot_freq, internal->mclk);
-				reg = stb0899_read_reg(state, STB0899_CFD);
-				STB0899_SETFIELD_VAL(CFD_ON, reg, 1);
-				stb0899_write_reg(state, STB0899_CFD, reg);
-
-				STB0899_SETFIELD_VAL(CFRM, cfr[0], MSB(state->config-
>inversion * derot_freq));
-				STB0899_SETFIELD_VAL(CFRL, cfr[1], LSB(state->config-
>inversion * derot_freq));
-				stb0899_write_regs(state, STB0899_CFRM, cfr, 2); /* derotator 
frequency	*/
-
-				stb0899_check_carrier(state);
-				index++;
-			}
+		if ((internal->status == CARRIEROK) &&
+		    (stb0899_check_data(state) == DATAOK)) {
+			/* get derotator frequency */
+			stb0899_read_regs(state, STB0899_CFRM, cfr, 2);
+			internal->derot_freq = state->config->inversion * 
MAKEWORD16(cfr[0], cfr[1]);
+			dprintk(state->verbose, FE_DEBUG, 1, "------> DATAOK ! Derot 
Freq=%d", internal->derot_freq);
+			break;
 		}
-		internal->direction = -internal->direction; /* change zig zag 
direction */
-	} while ((internal->status != DATAOK) && next_loop);
 
-	if (internal->status == DATAOK) {
-		stb0899_read_regs(state, STB0899_CFRM, cfr, 2); /* get derotator 
frequency */
-		internal->derot_freq = state->config->inversion * MAKEWORD16(cfr[0], 
cfr[1]);
-		dprintk(state->verbose, FE_DEBUG, 1, "------> DATAOK ! Derot Freq=%d", 
internal->derot_freq);
+		reg = stb0899_read_reg(state, STB0899_CFD);
+		STB0899_SETFIELD_VAL(CFD_ON, reg, 1);
+		stb0899_write_reg(state, STB0899_CFD, reg);
+
+		stb0899_check_carrier(state);
 	}
 
 	return internal->status;
@@ -508,8 +453,6 @@ enum stb0899_status stb0899_dvbs_algo(struct stb0899_state 
*state)
 		{ 37,  36,  33,	 32 }  /* QPSK 7/8	*/
 	};
 
-	internal->direction = 1;
-
 	stb0899_set_srate(state, internal->master_clk, params->srate);
 	/* Carrier loop optimization versus symbol rate for acquisition*/
 	if (params->srate <= 5000000) {
@@ -553,7 +496,6 @@ enum stb0899_status stb0899_dvbs_algo(struct stb0899_state 
*state)
 		internal->derot_percent, params->srate, internal->mclk);
 
 	/* Initial calculations	*/
-	internal->derot_step = internal->derot_percent * (params->srate / 1000L) / 
internal->mclk; /* DerotStep/1000 * Fsymbol	*/
 	internal->t_derot = stb0899_calc_derot_time(params->srate);
 	internal->t_data = 500;
 
diff --git a/drivers/media/dvb/frontends/stb0899_priv.h 
b/drivers/media/dvb/frontends/stb0899_priv.h
index 82395b9..d26ced5 100644
--- a/drivers/media/dvb/frontends/stb0899_priv.h
+++ b/drivers/media/dvb/frontends/stb0899_priv.h
@@ -176,8 +176,6 @@ struct stb0899_internal {
 	s16			derot_freq;		/* Current derotator frequency (Hz)	*/
 	s16			derot_percent;
 
-	s16			direction;		/* Current derotator search direction	*/
-	s16			derot_step;		/* Derotator step (binary value)	*/
 	s16			t_derot;		/* Derotator time constant (ms)		*/
 	s16			t_data;			/* Data recovery time constant (ms)	*/
 	s16			sub_dir;		/* Direction of the next sub range	*/
-- 
1.7.1.1


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2011-05-25  8:34 [PATCH v2] Fix the derot zig-zag to work with TT-USB2.0 TechnoTrend Hans Petter Selasky

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