From: Daniel Scheller <d.scheller@xxxxxxx>
Add signal-to-noise-ratio as provided by the demodulator in decibel scale.
QAM/DVB-C needs some intlog calculation to have usable dB values, OFDM/
DVB-T values from the demod look alright already and are provided as-is.
Signed-off-by: Daniel Scheller <d.scheller@xxxxxxx>
---
drivers/media/dvb-frontends/stv0367.c | 39 +++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/media/dvb-frontends/stv0367.c b/drivers/media/dvb-frontends/stv0367.c
index 9e5432b761b5..138f859d0f25 100644
--- a/drivers/media/dvb-frontends/stv0367.c
+++ b/drivers/media/dvb-frontends/stv0367.c
@@ -25,6 +25,8 @@
#include <linux/slab.h>
#include <linux/i2c.h>
+#include "dvb_math.h"
+
#include "stv0367.h"
#include "stv0367_defs.h"
#include "stv0367_regs.h"
@@ -3009,6 +3011,37 @@ static int stv0367ddb_set_frontend(struct dvb_frontend *fe)
return -EINVAL;
}
+static void stv0367ddb_read_snr(struct dvb_frontend *fe)
+{
+ struct stv0367_state *state = fe->demodulator_priv;
+ struct dtv_frontend_properties *p = &fe->dtv_property_cache;
+ int cab_pwr;
+ u32 regval, tmpval, snrval = 0;
+
+ switch (state->activedemod) {
+ case demod_ter:
+ snrval = stv0367ter_snr_readreg(fe);
+ break;
+ case demod_cab:
+ cab_pwr = stv0367cab_snr_power(fe);
+ regval = stv0367cab_snr_readreg(fe, 0);
+
+ /* prevent division by zero */
+ if (!regval)
+ snrval = 0;
+
+ tmpval = (cab_pwr * 320) / regval;
+ snrval = ((tmpval != 0) ? (intlog2(tmpval) / 5581) : 0);
+ break;
+ default:
+ p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+ return;
+ }
+
+ p->cnr.stat[0].scale = FE_SCALE_DECIBEL;
+ p->cnr.stat[0].uvalue = snrval;
+}
+
static void stv0367ddb_read_ucblocks(struct dvb_frontend *fe)
{
struct stv0367_state *state = fe->demodulator_priv;
@@ -3053,6 +3086,12 @@ static int stv0367ddb_read_status(struct dvb_frontend *fe,
if (ret)
return ret;
+ /* read carrier/noise when a carrier is detected */
+ if (*status & FE_HAS_CARRIER)
+ stv0367ddb_read_snr(fe);
+ else
+ p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+
/* stop if demod isn't locked */
if (!(*status & FE_HAS_LOCK)) {
p->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
--
2.13.0
