[media] mb86a20s: some fixes at preBER logic

The logic that resets the device is wrong. It should be resetting
just the layer that got read. Also, stop is needed before updating
the counters.
While there, rename it, as we'll soon introduce a postBER logic
there.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb-frontends/mb86a20s.c

@@ -785,12 +785,12 @@ static int mb86a20s_reset_counters(struct dvb_frontend *fe)
 	return rc;
 }
 
-static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
-					  unsigned layer,
-					  u32 *error, u32 *count)
+static int mb86a20s_get_pre_ber(struct dvb_frontend *fe,
+				unsigned layer,
+				u32 *error, u32 *count)
 {
 	struct mb86a20s_state *state = fe->demodulator_priv;
-	int rc;
+	int rc, val;
 
 	dev_dbg(&state->i2c->dev, "%s called.\n", __func__);
 
@@ -805,7 +805,7 @@ static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
 	/* Check if data is available for that layer */
 	if (!(rc & (1 << layer))) {
 		dev_dbg(&state->i2c->dev,
-			"%s: BER for layer %c is not available yet.\n",
+			"%s: preBER for layer %c is not available yet.\n",
 			__func__, 'A' + layer);
 		return -EBUSY;
 	}
@@ -866,8 +866,13 @@ static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
 	if (state->estimated_rate[layer]
 	    && state->estimated_rate[layer] != *count) {
 		dev_dbg(&state->i2c->dev,
-			"%s: updating layer %c counter to %d.\n",
+			"%s: updating layer %c preBER counter to %d.\n",
 			__func__, 'A' + layer, state->estimated_rate[layer]);
+
+		/* Turn off BER before Viterbi */
+		rc = mb86a20s_writereg(state, 0x52, 0x00);
+
+		/* Update counter for this layer */
 		rc = mb86a20s_writereg(state, 0x50, 0xa7 + layer * 3);
 		if (rc < 0)
 			return rc;
@@ -889,16 +894,39 @@ static int mb86a20s_get_ber_before_vterbi(struct dvb_frontend *fe,
 				       state->estimated_rate[layer]);
 		if (rc < 0)
 			return rc;
+
+		/* Turn on BER before Viterbi */
+		rc = mb86a20s_writereg(state, 0x52, 0x01);
+
+		/* Reset all preBER counters */
+		rc = mb86a20s_writereg(state, 0x53, 0x00);
+		if (rc < 0)
+			return rc;
+		rc = mb86a20s_writereg(state, 0x53, 0x07);
+	} else {
+		/* Reset counter to collect new data */
+		rc = mb86a20s_readreg(state, 0x53);
+		if (rc < 0)
+			return rc;
+		val = rc;
+		rc = mb86a20s_writereg(state, 0x53, val & ~(1 << layer));
+		if (rc < 0)
+			return rc;
+		rc = mb86a20s_writereg(state, 0x53, val | (1 << layer));
 	}
 
 
 	/* Reset counter to collect new data */
-	rc = mb86a20s_writereg(state, 0x53, 0x07 & ~(1 << layer));
+	rc = mb86a20s_readreg(state, 0x5f);
 	if (rc < 0)
 		return rc;
-	rc = mb86a20s_writereg(state, 0x53, 0x07);
+	val = rc;
+	rc = mb86a20s_writereg(state, 0x5f, val & ~(1 << layer));
+	if (rc < 0)
+		return rc;
+	rc = mb86a20s_writereg(state, 0x5f, val);
 
-	return 0;
+	return rc;
 }
 
 static int mb86a20s_get_blk_error(struct dvb_frontend *fe,
@@ -1401,9 +1429,8 @@ static int mb86a20s_get_stats(struct dvb_frontend *fe)
 
 			/* Read per-layer BER */
 			/* Handle BER before vterbi */
-			rc = mb86a20s_get_ber_before_vterbi(fe, i,
-							&bit_error,
-							&bit_count);
+			rc = mb86a20s_get_pre_ber(fe, i,
+						  &bit_error, &bit_count);
 			if (rc >= 0) {
 				c->pre_bit_error.stat[1 + i].scale = FE_SCALE_COUNTER;
 				c->pre_bit_error.stat[1 + i].uvalue += bit_error;