summaryrefslogtreecommitdiffstats
path: root/drivers/media
diff options
context:
space:
mode:
authorAntti Palosaari <crope@iki.fi>2012-05-15 18:32:33 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-05-20 10:23:18 -0300
commiteba672a045d8fbf62b229eac74ef444b6000c4c2 (patch)
tree2247309bf56ecc8b51b07c0c08c8ca61fc2f9e56 /drivers/media
parentf6f379df6516d6fab27367706fcaafa88df41178 (diff)
downloadblackbird-op-linux-eba672a045d8fbf62b229eac74ef444b6000c4c2.tar.gz
blackbird-op-linux-eba672a045d8fbf62b229eac74ef444b6000c4c2.zip
[media] rtl2830: implement .read_snr()
Reports value as a 0.1 dB. Signed-off-by: Antti Palosaari <crope@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/dvb/frontends/rtl2830.c42
-rw-r--r--drivers/media/dvb/frontends/rtl2830_priv.h1
2 files changed, 42 insertions, 1 deletions
diff --git a/drivers/media/dvb/frontends/rtl2830.c b/drivers/media/dvb/frontends/rtl2830.c
index 45196c5b0736..e6d7c501717a 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) & 0x07; /* [6:4] */
+ 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 4a464761b5b8..9b20557ccf6c 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"
OpenPOWER on IntegriCloud