From 971e541a4924db380c290cb784f30f9d141ff1d4 Mon Sep 17 00:00:00 2001
From: Antti Palosaari <crope@iki.fi>
Date: Tue, 21 Aug 2012 19:56:21 -0300
Subject: [PATCH] --- yaml --- r: 330983 b: refs/heads/master c:
 73983497ff816109e2739ad23ace06fd42c552e9 h: refs/heads/master i:   330981:
 7fa83344d7535409d10f1e1032c044ac6b1c3114   330979:
 953a1704a47630e654134d1d72b697842c309311   330975:
 5820be86e5057ce5c5bf633ed0539ee167165baa v: v3

---
 [refs]                                      |  2 +-
 trunk/drivers/media/dvb-frontends/rtl2832.c | 52 +++++++++++++++++++--
 2 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index c4c2dec79162..5a36b4e820c9 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0ce67a2a59b26dd1b087115141c71ddd89514b77
+refs/heads/master: 73983497ff816109e2739ad23ace06fd42c552e9
diff --git a/trunk/drivers/media/dvb-frontends/rtl2832.c b/trunk/drivers/media/dvb-frontends/rtl2832.c
index 6e28444d6526..dad8ab5aba8e 100644
--- a/trunk/drivers/media/dvb-frontends/rtl2832.c
+++ b/trunk/drivers/media/dvb-frontends/rtl2832.c
@@ -19,6 +19,7 @@
  */
 
 #include "rtl2832_priv.h"
+#include "dvb_math.h"
 #include <linux/bitops.h>
 
 int rtl2832_debug;
@@ -355,7 +356,6 @@ int rtl2832_wr_demod_reg(struct rtl2832_priv *priv, int reg, u32 val)
 
 }
 
-
 static int rtl2832_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
 {
 	int ret;
@@ -379,8 +379,6 @@ static int rtl2832_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
 	return ret;
 }
 
-
-
 static int rtl2832_init(struct dvb_frontend *fe)
 {
 	struct rtl2832_priv *priv = fe->demodulator_priv;
@@ -780,6 +778,52 @@ static int rtl2832_read_status(struct dvb_frontend *fe, fe_status_t *status)
 	return ret;
 }
 
+static int rtl2832_read_snr(struct dvb_frontend *fe, u16 *snr)
+{
+	struct rtl2832_priv *priv = fe->demodulator_priv;
+	int ret, hierarchy, constellation;
+	u8 buf[2], tmp;
+	u16 tmp16;
+#define CONSTELLATION_NUM 3
+#define HIERARCHY_NUM 4
+	static const u32 snr_constant[CONSTELLATION_NUM][HIERARCHY_NUM] = {
+		{ 85387325, 85387325, 85387325, 85387325 },
+		{ 86676178, 86676178, 87167949, 87795660 },
+		{ 87659938, 87659938, 87885178, 88241743 },
+	};
+
+	/* reports SNR in resolution of 0.1 dB */
+
+	ret = rtl2832_rd_reg(priv, 0x3c, 3, &tmp);
+	if (ret)
+		goto err;
+
+	constellation = (tmp >> 2) & 0x03; /* [3:2] */
+	if (constellation > CONSTELLATION_NUM - 1)
+		goto err;
+
+	hierarchy = (tmp >> 4) & 0x07; /* [6:4] */
+	if (hierarchy > HIERARCHY_NUM - 1)
+		goto err;
+
+	ret = rtl2832_rd_regs(priv, 0x0c, 4, buf, 2);
+	if (ret)
+		goto err;
+
+	tmp16 = buf[0] << 8 | buf[1];
+
+	if (tmp16)
+		*snr = (snr_constant[constellation][hierarchy] -
+				intlog10(tmp16)) / ((1 << 24) / 100);
+	else
+		*snr = 0;
+
+	return 0;
+err:
+	dbg("%s: failed=%d", __func__, ret);
+	return ret;
+}
+
 static struct dvb_frontend_ops rtl2832_ops;
 
 static void rtl2832_release(struct dvb_frontend *fe)
@@ -864,6 +908,8 @@ static struct dvb_frontend_ops rtl2832_ops = {
 	.get_frontend = rtl2832_get_frontend,
 
 	.read_status = rtl2832_read_status,
+	.read_snr = rtl2832_read_snr,
+
 	.i2c_gate_ctrl = rtl2832_i2c_gate_ctrl,
 };