From 20e28228950f2e54c99e5143404bfc657468eff0 Mon Sep 17 00:00:00 2001
From: Jean Delvare <khali@linux-fr.org>
Date: Sun, 12 Feb 2012 15:03:03 -0300
Subject: [PATCH] --- yaml --- r: 294995 b: refs/heads/master c:
 06302ffbb470359c8cbcf1ee8b057d6930300f90 h: refs/heads/master i:   294993:
 871861bb0188f6cd6355a25d86aa2008bba1e951   294991:
 de6e998954b2716f3085fff483898bf046db222e v: v3

---
 [refs]                                      |  2 +-
 trunk/drivers/media/dvb/frontends/cx22702.c | 22 ++++++++++++++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 7ca10a45080a..de660444da9a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6c5637e4eda58292f7d9ee6ee0b1f9aa4b0a7e7f
+refs/heads/master: 06302ffbb470359c8cbcf1ee8b057d6930300f90
diff --git a/trunk/drivers/media/dvb/frontends/cx22702.c b/trunk/drivers/media/dvb/frontends/cx22702.c
index faba82485086..edc8eafc5c09 100644
--- a/trunk/drivers/media/dvb/frontends/cx22702.c
+++ b/trunk/drivers/media/dvb/frontends/cx22702.c
@@ -502,10 +502,26 @@ static int cx22702_read_signal_strength(struct dvb_frontend *fe,
 	u16 *signal_strength)
 {
 	struct cx22702_state *state = fe->demodulator_priv;
+	u8 reg23;
 
-	u16 rs_ber;
-	rs_ber = cx22702_readreg(state, 0x23);
-	*signal_strength = (rs_ber << 8) | rs_ber;
+	/*
+	 * Experience suggests that the strength signal register works as
+	 * follows:
+	 * - In the absence of signal, value is 0xff.
+	 * - In the presence of a weak signal, bit 7 is set, not sure what
+	 *   the lower 7 bits mean.
+	 * - In the presence of a strong signal, the register holds a 7-bit
+	 *   value (bit 7 is cleared), with greater values standing for
+	 *   weaker signals.
+	 */
+	reg23 = cx22702_readreg(state, 0x23);
+	if (reg23 & 0x80) {
+		*signal_strength = 0;
+	} else {
+		reg23 = ~reg23 & 0x7f;
+		/* Scale to 16 bit */
+		*signal_strength = (reg23 << 9) | (reg23 << 2) | (reg23 >> 5);
+	}
 
 	return 0;
 }