Reports value as a 0.1 dB.
Signed-off-by: Antti Palosaari <cr...@iki.fi>
---
drivers/media/dvb/frontends/rtl2830.c | 42 +++++++++++++++++++++++++++-
drivers/media/dvb/frontends/rtl2830_priv.h | 1 +
2 files changed, 42 insertions(+), 1 deletions(-)
diff --git a/drivers/media/dvb/frontends/rtl2830.c
b/drivers/media/dvb/frontends/rtl2830.c
index 45196c5..bd18dbe 100644
--- a/drivers/media/dvb/frontends/rtl2830.c
+++ b/drivers/media/dvb/frontends/rtl2830.c
@@ -404,8 +404,48 @@ err:
static int rtl2830_read_snr(struct dvb_frontend *fe, u16 *snr)
{
- *snr = 0;
+ struct rtl2830_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] = {
+ { 70705899, 70705899, 70705899, 70705899 },
+ { 82433173, 82433173, 87483115, 94445660 },
+ { 92888734, 92888734, 95487525, 99770748 },
+ };
+
+ /* reports SNR in resolution of 0.1 dB */
+
+ ret = rtl2830_rd_reg(priv, 0x33c, &tmp);
+ if (ret)
+ goto err;
+
+ constellation = (tmp >> 2) & 0x03; /* [3:2] */
+ if (constellation > CONSTELLATION_NUM - 1)
+ goto err;
+
+ hierarchy = (tmp >> 4) & 0x03; /* [5:4] */
+ if (hierarchy > HIERARCHY_NUM - 1)
+ goto err;
+
+ ret = rtl2830_rd_regs(priv, 0x40c, 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 int rtl2830_read_ber(struct dvb_frontend *fe, u32 *ber)
diff --git a/drivers/media/dvb/frontends/rtl2830_priv.h
b/drivers/media/dvb/frontends/rtl2830_priv.h
index 4a46476..9b20557 100644
--- a/drivers/media/dvb/frontends/rtl2830_priv.h
+++ b/drivers/media/dvb/frontends/rtl2830_priv.h
@@ -22,6 +22,7 @@
#define RTL2830_PRIV_H
#include "dvb_frontend.h"
+#include "dvb_math.h"
#include "rtl2830.h"
#define LOG_PREFIX "rtl2830"
--
1.7.7.6
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
