From df61f828d4e5f6db7936a21afeef1d5cb6248b4b Mon Sep 17 00:00:00 2001 From: Daniel Scheller Date: Sun, 9 Apr 2017 16:38:24 -0300 Subject: [PATCH] [media] dvb-frontends/cxd2841er: improved snr reporting On DVB-T/T2 at least, SNR might be reported as >2500dB, which not only is just wrong but also ridiculous, so fix this by improving the conversion of the register value. The INTLOG10X100 function/macro and the way the values are converted were both taken from DD's cxd2843 driver. Signed-off-by: Daniel Scheller Acked-by: Abylay Ospan Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-frontends/cxd2841er.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/media/dvb-frontends/cxd2841er.c b/drivers/media/dvb-frontends/cxd2841er.c index d9e8be50c5fa..08f67d60a7d9 100644 --- a/drivers/media/dvb-frontends/cxd2841er.c +++ b/drivers/media/dvb-frontends/cxd2841er.c @@ -38,6 +38,8 @@ #define MAX_WRITE_REGSIZE 16 #define LOG2_E_100X 144 +#define INTLOG10X100(x) ((u32) (((u64) intlog10(x) * 100) >> 24)) + /* DVB-C constellation */ enum sony_dvbc_constellation_t { SONY_DVBC_CONSTELLATION_16QAM, @@ -1817,7 +1819,7 @@ static int cxd2841er_read_snr_t(struct cxd2841er_priv *priv, u32 *snr) } if (reg > 4996) reg = 4996; - *snr = 10000 * ((intlog10(reg) - intlog10(5350 - reg)) >> 24) + 28500; + *snr = 100 * ((INTLOG10X100(reg) - INTLOG10X100(5350 - reg)) + 285); return 0; } @@ -1846,8 +1848,7 @@ static int cxd2841er_read_snr_t2(struct cxd2841er_priv *priv, u32 *snr) } if (reg > 10876) reg = 10876; - *snr = 10000 * ((intlog10(reg) - - intlog10(12600 - reg)) >> 24) + 32000; + *snr = 100 * ((INTLOG10X100(reg) - INTLOG10X100(12600 - reg)) + 320); return 0; } -- 2.20.1