From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mauro Carvalho Chehab Subject: Re: [PATCH 21/66] rtl2830: implement own I2C locking Date: Tue, 3 Feb 2015 15:53:01 -0200 Message-ID: <20150203155301.7ba63776@recife.lan> References: <1419367799-14263-1-git-send-email-crope@iki.fi> <1419367799-14263-21-git-send-email-crope@iki.fi> <20150202180726.454dc878@recife.lan> <54CFDCCC.3030006@iki.fi> <20150202203324.GA11486@katana> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; boundary="Sig_/vlc4iJA=hRPVu/H5BVxFEdq"; protocol="application/pgp-signature" Return-path: In-Reply-To: <20150202203324.GA11486@katana> Sender: linux-media-owner@vger.kernel.org To: Wolfram Sang Cc: Antti Palosaari , Mark Brown , Lars-Peter Clausen , linux-i2c@vger.kernel.org, linux-media@vger.kernel.org, Jean Delvare List-Id: linux-i2c@vger.kernel.org --Sig_/vlc4iJA=hRPVu/H5BVxFEdq Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Em Mon, 02 Feb 2015 21:33:24 +0100 Wolfram Sang escreveu: >=20 > > >Ok, this may eventually work ok for now, but a further change at the I= 2C > > >core could easily break it. So, we need to double check about such > > >patch with the I2C maintainer. > > > > > >Jean, > > > > > >Are you ok with such patch? If so, please ack. >=20 > Jean handed over I2C to me in late 2012 :) Sorry for the mess... I mis-read MAINTAINERS. > > Basic problem here is that I2C-mux itself is controlled by same I2C dev= ice > > which implements I2C adapter for tuner. > >=20 > > Here is what connections looks like: > > ___________ ____________ ____________ > > | USB IF | | demod | | tuner | > > |-----------| |------------| |------------| > > | |--I2C--|-----/ -----|--I2C--| | > > |I2C master | | I2C mux | | I2C slave | > > |___________| |____________| |____________| > >=20 > >=20 > > So when tuner is called via I2C, it needs recursively call same I2C ada= pter > > which is already locked. More elegant solution would be indeed nice. >=20 > So, AFAIU this is the same problem that I2C based mux devices have (like > drivers/i2c/muxes/i2c-mux-pca954x.c)? They also use the unlocked > transfers... If I understood your comment correct, you're ok with this approach, right? I'll then merge the remaining of this 66-patch series. If latter a better way to lock the I2C mux appears, we can reverse this change. Regards, Mauro >=20 --Sig_/vlc4iJA=hRPVu/H5BVxFEdq Content-Type: application/pgp-signature Content-Description: Assinatura digital OpenPGP -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJU0QsFAAoJEAhfPr2O5OEVQWoP/3pSoFGkdT+Cq8m9sv0iHul/ V4V+vIn7DVqTRc98oM6Ehtu+BubBR6pAKQiN6XQNQJBg+acB4nVO/nukjbbZmIRh M335nepmqaMFUAPS1+43vVqgN+w9hqBmlTSUn0SUGw76z2h5jWP2DlMxAlnBayvs XochsQNkjPAD9dfNRAiU+wE0PysfE5RBAuZC767S69X2+dLUyKuo+UzdIN2ZczyK E7DJIfyTCEUP9qyuwk3rudLoxVNCVnjnz5gbBZAvHRqlotE1cC4UY5GY13tmKUIp lnYv1fDjWDtR8w0n00UNnq6fT+xz2ANyPgTbBVxQCIC9Eq5D2237LTPRiFr/Ke1n hhuH69geST8GxquBOnc3G3lNHES2lj72v+msg6eKcwfTC7S5dPBHcMV6DMvKV+Qw LzrPfh5bG4cJqz5t8bM80IXjxPJhk2TFihPwBwxmaQ3lGFwozgqvmEs65etiGZJP 6vx16qUK0Goz8kvxTXwa9j5Ea4VuYRPT2Fiz4VDqoPNCiKGw0RBaCy/bKpJXsyKE ZvShe0E/cSgWHfAKo/NwWV6+RlVTeeg93+9kGlhd641/Jkmy6rW1zKSMb8HRgSho sn4pIUZ5JYb+GxFgpvzIGvniKTs1e/ZHByRGuXbXMVUxrcvyH3wq0oag2xsQFlOg 0x5HOZGlM9cQTqjyyaHY =1fer -----END PGP SIGNATURE----- --Sig_/vlc4iJA=hRPVu/H5BVxFEdq--