[media] af9033: fix DVBv3 signal strength value not correct issue

Register 0x800048 is not dB measure but relative scale. Fix it and conform to NorDig specifications.

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

2 files changed, 41 insertions, 8 deletions

diff --git a/drivers/media/dvb-frontends/af9033.c b/drivers/media/dvb-frontends/af9033.c
index 63a89c1c59ff..2b3d2f06c01b 100644
--- a/drivers/media/dvb-frontends/af9033.c
+++ b/drivers/media/dvb-frontends/af9033.c
@@ -862,16 +862,43 @@ static int af9033_read_snr(struct dvb_frontend *fe, u16 *snr)
 static int af9033_read_signal_strength(struct dvb_frontend *fe, u16 *strength)
 {
         struct af9033_dev *dev = fe->demodulator_priv;
-        int ret;
-        u8 strength2;
+        struct dtv_frontend_properties *c = &dev->fe.dtv_property_cache;
+        int ret, tmp, power_real;
+        u8 u8tmp, gain_offset, buf[7];
 
-        /* read signal strength of 0-100 scale */
-        ret = af9033_rd_reg(dev, 0x800048, &strength2);
-        if (ret < 0)
-                goto err;
+        if (dev->is_af9035) {
+                ret = af9033_rd_reg(dev, 0x80004a, &u8tmp);
+                /* scale value to 0x0000-0xffff */
+                *strength = u8tmp * 0xffff / 100;
+        } else {
+                ret = af9033_rd_reg(dev, 0x8000f7, &u8tmp);
+                ret |= af9033_rd_regs(dev, 0x80f900, buf, 7);
+
+                if (c->frequency <= 300000000)
+                        gain_offset = 7; /* VHF */
+                else
+                        gain_offset = 4; /* UHF */
+
+                power_real = (u8tmp - 100 - gain_offset) -
+                        power_reference[((buf[3] >> 0) & 3)][((buf[6] >> 0) & 7)];
+
+                if (power_real < -15)
+                        tmp = 0;
+                else if ((power_real >= -15) && (power_real < 0))
+                        tmp = (2 * (power_real + 15)) / 3;
+                else if ((power_real >= 0) && (power_real < 20))
+                        tmp = 4 * power_real + 10;
+                else if ((power_real >= 20) && (power_real < 35))
+                        tmp = (2 * (power_real - 20)) / 3 + 90;
+                else
+                        tmp = 100;
+
+                /* scale value to 0x0000-0xffff */
+                *strength = tmp * 0xffff / 100;
+        }
 
-        /* scale value to 0x0000-0xffff */
-        *strength = strength2 * 0xffff / 100;
+        if (ret)
+                goto err;
 
         return 0;
 
diff --git a/drivers/media/dvb-frontends/af9033_priv.h b/drivers/media/dvb-frontends/af9033_priv.h
index c12c92cb5855..c9c87981f80b 100644
--- a/drivers/media/dvb-frontends/af9033_priv.h
+++ b/drivers/media/dvb-frontends/af9033_priv.h
@@ -2051,4 +2051,10 @@ static const struct reg_val tuner_init_it9135_62[] = {
         { 0x80fd8b, 0x00 },
 };
 
+/* NorDig power reference table */
+static const int power_reference[][5] = {
+        {-93, -91, -90, -89, -88}, /* QPSK 1/2 ~ 7/8 */
+        {-87, -85, -84, -83, -82}, /* 16QAM 1/2 ~ 7/8 */
+        {-82, -80, -78, -77, -76}, /* 64QAM 1/2 ~ 7/8 */
+};
 #endif /* AF9033_PRIV_H */