From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:35150 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750748AbaJDE0T (ORCPT ); Sat, 4 Oct 2014 00:26:19 -0400 Message-ID: <542F76E5.8080601@iki.fi> Date: Sat, 04 Oct 2014 07:26:13 +0300 From: Antti Palosaari MIME-Version: 1.0 To: Bimow Chen , linux-media@vger.kernel.org Subject: Re: [PATCH 1/2] af9033: fix DVBv3 signal strength value not correct issue References: <1412227954.1699.2.camel@ite-desktop> In-Reply-To: <1412227954.1699.2.camel@ite-desktop> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Hello I did some review and testing. Before that patch, IT9133 DVBv3 signal strength measurement was broken - it returned 0xffff all the time. After that is returns some realistic values between 0-0xffff. Anyhow, AF9033 chip version it worked earlier too, just like old comment says hw returns 0-100, which was scaled to 0-0xffff. AF9033 and IT9133 firmware differs on signal strength measurement. For AF9033 it provides both percentage and dBm reports, for IT9133 I know only dBm report. AF9033: 0x800048 relative (0-100, percentage) 0x80004a decibel (-VAL dBm) IT9133: 0x8000f7 decibel (VAL - 100 dBm) Now you changed that AF9033 implementation from 0x800048 (percentage) to 0x80004a (dBm) and scale that to 0-0xffff, which results poorer result than old implementation calculated by firmware. What I tested that implementation, it gives maximum value 0x6e14, which we could calc is 43dBm. I was using -18dBm RF level (which is very very strong), so I suspect that 43dBm is maximum what firmware even could report. Having maximum possible signal strength only 43% (out of 100%) is not nice. So I ask you change AF9035 as it has been (percentage reported by FW). Change only non-working IT9135 what you like. Also, add error checking just after register reads and jump out if fails. regards Antti On 10/02/2014 08:32 AM, Bimow Chen wrote: > Register 0x800048 is not dB measure but relative scale. Fix it and conform to NorDig specifications. > > > 0001-af9033-fix-DVBv3-signal-strength-value-not-correct-i.patch > > >>>From 02ee7de4600a43a322f75cf04d273effa04d3a42 Mon Sep 17 00:00:00 2001 > From: Bimow Chen > Date: Wed, 1 Oct 2014 18:28:54 +0800 > Subject: [PATCH 1/2] 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 > --- > drivers/media/dvb-frontends/af9033.c | 43 +++++++++++++++++++++++----- > drivers/media/dvb-frontends/af9033_priv.h | 6 ++++ > 2 files changed, 41 insertions(+), 8 deletions(-) > > diff --git a/drivers/media/dvb-frontends/af9033.c b/drivers/media/dvb-frontends/af9033.c > index 63a89c1..2b3d2f0 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 c12c92c..c9c8798 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 */ > -- 1.7.0.4 > -- http://palosaari.fi/