V4L/DVB (6402): s5h1409: Fix broken QAM support

This patch enables QAM Annex-B support (US digital cable)
for the s5h1409 VSB/QAM demodulator.

Tested successfully with the mt2131 tuner,
present on the following supported boards:

Hauppauge WinTV-HVR-1250
Hauppauge WinTV-HVR-1800
Hauppauge WinTV-HVR-1800lp

This patch is also known to work with an upcoming XC5000 tuner driver.
Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/frontends/s5h1409.c

@@ -42,6 +42,9 @@ struct s5h1409_state {
 	fe_modulation_t current_modulation;
 
 	u32 current_frequency;
+
+	u32 is_qam_locked;
+	u32 qam_state;
 };
 
 static int debug = 0;
@@ -94,6 +97,7 @@ static struct init_tab {
 	{ 0xac, 0x1003, },
 	{ 0xad, 0x103f, },
 	{ 0xe2, 0x0100, },
+	{ 0xe3, 0x0000, },
 	{ 0x28, 0x1010, },
 	{ 0xb1, 0x000e, },
 };
@@ -335,6 +339,8 @@ static int s5h1409_softreset(struct dvb_frontend* fe)
 
 	s5h1409_writereg(state, 0xf5, 0);
 	s5h1409_writereg(state, 0xf5, 1);
+	state->is_qam_locked = 0;
+	state->qam_state = 0;
 	return 0;
 }
 
@@ -349,6 +355,11 @@ static int s5h1409_set_if_freq(struct dvb_frontend* fe, int KHz)
 		s5h1409_writereg(state, 0x87, 0x01be);
 		s5h1409_writereg(state, 0x88, 0x0436);
 		s5h1409_writereg(state, 0x89, 0x054d);
+	} else
+	if (KHz == 4000) {
+		s5h1409_writereg(state, 0x87, 0x014b);
+		s5h1409_writereg(state, 0x88, 0x0cb5);
+		s5h1409_writereg(state, 0x89, 0x03e2);
 	} else {
 		printk("%s() Invalid arg = %d KHz\n", __FUNCTION__, KHz);
 		ret = -1;
@@ -361,7 +372,7 @@ static int s5h1409_set_spectralinversion(struct dvb_frontend* fe, int inverted)
 {
 	struct s5h1409_state* state = fe->demodulator_priv;
 
-	dprintk("%s()\n", __FUNCTION__);
+	dprintk("%s(%d)\n", __FUNCTION__, inverted);
 
 	if(inverted == 1)
 		return s5h1409_writereg(state, 0x1b, 0x1101); /* Inverted */
@@ -382,14 +393,10 @@ static int s5h1409_enable_modulation(struct dvb_frontend* fe,
 		s5h1409_writereg(state, 0xf4, 0);
 		break;
 	case QAM_64:
-		dprintk("%s() QAM_64\n", __FUNCTION__);
-		s5h1409_writereg(state, 0xf4, 1);
-		s5h1409_writereg(state, 0x85, 0x100);
-		break;
 	case QAM_256:
-		dprintk("%s() QAM_256\n", __FUNCTION__);
+		dprintk("%s() QAM_AUTO (64/256)\n", __FUNCTION__);
 		s5h1409_writereg(state, 0xf4, 1);
-		s5h1409_writereg(state, 0x85, 0x101);
+		s5h1409_writereg(state, 0x85, 0x110);
 		break;
 	default:
 		dprintk("%s() Invalid modulation\n", __FUNCTION__);
@@ -423,7 +430,7 @@ static int s5h1409_set_gpio(struct dvb_frontend* fe, int enable)
 	if (enable)
 		return s5h1409_writereg(state, 0xe3, 0x1100);
 	else
-		return s5h1409_writereg(state, 0xe3, 0);
+		return s5h1409_writereg(state, 0xe3, 0x1000);
 }
 
 static int s5h1409_sleep(struct dvb_frontend* fe, int enable)
@@ -444,6 +451,66 @@ static int s5h1409_register_reset(struct dvb_frontend* fe)
 	return s5h1409_writereg(state, 0xfa, 0);
 }
 
+static void s5h1409_set_qam_amhum_mode(struct dvb_frontend *fe)
+{
+	struct s5h1409_state *state = fe->demodulator_priv;
+	u16 reg;
+
+	if (state->is_qam_locked)
+		return;
+
+	/* QAM EQ lock check */
+	reg = s5h1409_readreg(state, 0xf0);
+
+	if ((reg >> 13) & 0x1) {
+
+		state->is_qam_locked = 1;
+		reg &= 0xff;
+
+		s5h1409_writereg(state, 0x96, 0x00c);
+		if ((reg < 0x38) || (reg > 0x68) ) {
+			s5h1409_writereg(state, 0x93, 0x3332);
+			s5h1409_writereg(state, 0x9e, 0x2c37);
+		} else {
+			s5h1409_writereg(state, 0x93, 0x3130);
+			s5h1409_writereg(state, 0x9e, 0x2836);
+		}
+
+	} else {
+		s5h1409_writereg(state, 0x96, 0x0008);
+		s5h1409_writereg(state, 0x93, 0x3332);
+		s5h1409_writereg(state, 0x9e, 0x2c37);
+	}
+}
+
+static void s5h1409_set_qam_interleave_mode(struct dvb_frontend *fe)
+{
+	struct s5h1409_state *state = fe->demodulator_priv;
+	u16 reg, reg1, reg2;
+
+	reg = s5h1409_readreg(state, 0xf1);
+
+	/* Master lock */
+	if ((reg >> 15) & 0x1) {
+		if (state->qam_state != 2) {
+			state->qam_state = 2;
+			reg1 = s5h1409_readreg(state, 0xb2);
+			reg2 = s5h1409_readreg(state, 0xad);
+
+			s5h1409_writereg(state, 0x96, 0x20);
+			s5h1409_writereg(state, 0xad,
+				( ((reg1 & 0xf000) >> 4) | (reg2 & 0xf0ff)) );
+			s5h1409_writereg(state, 0xab, 0x1100);
+		}
+	} else {
+		if (state->qam_state != 1) {
+			state->qam_state = 1;
+			s5h1409_writereg(state, 0x96, 0x08);
+			s5h1409_writereg(state, 0xab, 0x1101);
+		}
+	}
+}
+
 /* Talk to the demod, set the FEC, GUARD, QAM settings etc */
 static int s5h1409_set_frontend (struct dvb_frontend* fe,
 				 struct dvb_frontend_parameters *p)
@@ -458,12 +525,21 @@ static int s5h1409_set_frontend (struct dvb_frontend* fe,
 
 	s5h1409_enable_modulation(fe, p->u.vsb.modulation);
 
+	/* Allow the demod to settle */
+	msleep(100);
+
 	if (fe->ops.tuner_ops.set_params) {
 		if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 1);
 		fe->ops.tuner_ops.set_params(fe, p);
 		if (fe->ops.i2c_gate_ctrl) fe->ops.i2c_gate_ctrl(fe, 0);
 	}
 
+	/* Optimize the demod for QAM */
+	if (p->u.vsb.modulation != VSB_8) {
+		s5h1409_set_qam_amhum_mode(fe);
+		s5h1409_set_qam_interleave_mode(fe);
+	}
+
 	return 0;
 }
 
@@ -495,8 +571,8 @@ static int s5h1409_init (struct dvb_frontend* fe)
 	s5h1409_set_gpio(fe, state->config->gpio);
 	s5h1409_softreset(fe);
 
-	/* Note: Leaving the I2C gate open here. */
-	s5h1409_i2c_gate_ctrl(fe, 1);
+	/* Note: Leaving the I2C gate closed. */
+	s5h1409_i2c_gate_ctrl(fe, 0);
 
 	return 0;
 }