[media] rtl2830: implement DVBv5 signal strength statistics

Estimate signal strength from IF AGC.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/media/dvb-frontends/rtl2830.c b/drivers/media/dvb-frontends/rtl2830.c
index c484634a9fc9..641047b89e05 100644
--- a/drivers/media/dvb-frontends/rtl2830.c
+++ b/drivers/media/dvb-frontends/rtl2830.c
@@ -246,6 +246,8 @@ static int rtl2830_init(struct dvb_frontend *fe)
                 goto err;
 
         /* init stats here in order signal app which stats are supported */
+        c->strength.len = 1;
+        c->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         c->cnr.len = 1;
         c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
         /* start statistics polling */
@@ -693,6 +695,28 @@ static void rtl2830_stat_work(struct work_struct *work)
 
         dev_dbg(&client->dev, "\n");
 
+        /* signal strength */
+        if (dev->fe_status & FE_HAS_SIGNAL) {
+                struct {signed int x:14; } s;
+
+                /* read IF AGC */
+                ret = rtl2830_rd_regs(client, 0x359, buf, 2);
+                if (ret)
+                        goto err;
+
+                u16tmp = buf[0] << 8 | buf[1] << 0;
+                u16tmp &= 0x3fff; /* [13:0] */
+                tmp = s.x = u16tmp; /* 14-bit bin to 2 complement */
+                u16tmp = clamp_val(-4 * tmp + 32767, 0x0000, 0xffff);
+
+                dev_dbg(&client->dev, "IF AGC=%d\n", tmp);
+
+                c->strength.stat[0].scale = FE_SCALE_RELATIVE;
+                c->strength.stat[0].uvalue = u16tmp;
+        } else {
+                c->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+        }
+
         /* CNR */
         if (dev->fe_status & FE_HAS_VITERBI) {
                 unsigned hierarchy, constellation;