From: Jemma Denson <jdenson@gmail.com>
Date: Tue, 5 May 2015 21:09:45 +0000 (-0300)
Subject: [media] cx24120: Improve cooked signal strength value
X-Git-Tag: v4.2-rc8~12^2~294
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b0cdf1a16f4058ac1c6c595455f276c5e3c54db3;p=platform%2Fkernel%2Flinux-exynos.git

[media] cx24120: Improve cooked signal strength value

Algorithm copied from cx24117.c - it seems to work. Showing 95% on
a signal I know to be somewhere around 74dBuV.

[mchehab@osg.samsung.net: merged two patches, to avoid breaking compilation]
Signed-off-by: Jemma Denson <jdenson@gmail.com>
Signed-off-by: Patrick Boettcher <patrick.boettcher@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
---

diff --git a/drivers/media/dvb-frontends/cx24120.c b/drivers/media/dvb-frontends/cx24120.c
index eecfe22..acdda03 100644
--- a/drivers/media/dvb-frontends/cx24120.c
+++ b/drivers/media/dvb-frontends/cx24120.c
@@ -608,8 +608,8 @@ static void cx24120_get_stats(struct cx24120_state *state)
 	struct dvb_frontend *fe = &state->frontend;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 	struct cx24120_cmd cmd;
-	int ret, sigstr_h, sigstr_l;
-	u16 u16tmp;
+	int ret;
+	u16 sig;
 
 	dev_dbg(&state->i2c->dev, "%s()\n", __func__);
 
@@ -626,18 +626,18 @@ static void cx24120_get_stats(struct cx24120_state *state)
 		}
 
 		/* raw */
-		sigstr_h = (cx24120_readreg(state, CX24120_REG_SIGSTR_H) >> 6) << 8;
-		sigstr_l = cx24120_readreg(state, CX24120_REG_SIGSTR_L);
-		dev_dbg(&state->i2c->dev, "%s: Signal strength from firmware= 0x%x\n",
-			__func__, (sigstr_h | sigstr_l));
+		sig = cx24120_readreg(state, CX24120_REG_SIGSTR_H) >> 6;
+		sig = sig << 8;
+		sig |= cx24120_readreg(state, CX24120_REG_SIGSTR_L);
+		dev_dbg(&state->i2c->dev,
+			"%s: Signal strength from firmware= 0x%x\n",
+			__func__, sig);
 
 		/* cooked */
-		u16tmp = ((sigstr_h | sigstr_l)  << 5) & 0x0000ffff;
-		dev_dbg(&state->i2c->dev, "%s: Signal strength= 0x%x\n",
-			__func__, u16tmp);
+		sig = -100 * sig + 94324;
 
 		c->strength.stat[0].scale = FE_SCALE_RELATIVE;
-		c->strength.stat[0].uvalue = u16tmp;
+		c->strength.stat[0].uvalue = sig;
 	} else {
 		c->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
 	}