From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.emlix.com ([193.175.82.87]:55563 "EHLO mx1.emlix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753805AbZC3MMS (ORCPT ); Mon, 30 Mar 2009 08:12:18 -0400 Message-ID: <49D0B71A.5080801@emlix.com> Date: Mon, 30 Mar 2009 14:12:10 +0200 From: =?ISO-8859-1?Q?Daniel_Gl=F6ckner?= MIME-Version: 1.0 To: Hans Verkuil CC: Mauro Carvalho Chehab , Chris Zankel , linux-media@vger.kernel.org Subject: Re: [patch 5/5] saa7121 driver for s6000 data port References: <13003.62.70.2.252.1238080086.squirrel@webmail.xs4all.nl> <49D09749.507@emlix.com> <200903301203.02327.hverkuil@xs4all.nl> In-Reply-To: <200903301203.02327.hverkuil@xs4all.nl> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On 03/30/2009 12:03 PM, Hans Verkuil wrote: > What exactly do you need? If there is something missing, then it should be > added. But my guess is that you can pass such information via the s_routing > callback. That's what all other drivers that use v4l2_subdev do. The s_routing callback looks very limited. One can pass only two u32 values. The parameters that have to be negotiated are: - What is the on-wire video format? - how many data lines are connected? - synchronization using embedded SAV/EAV codes or using dedicated pins? - polarity of sync lines? - valid CRC and line number in digital blanking? - what is the layout of the digital image? - how many odd lines are there? how many even? (including blanking) - how many horizontal pixels? (incl. blanking) - where is the active region? - on which pixels/lines do we start/end horizontal/vertical sync? >> It seems the soc-camera framework is a better choice here, but to make it >> work with the saa7121 one would first have to implement support for video >> output. > > This framework will also be converted to use v4l2_subdev for the > communication with i2c drivers. So it shouldn't matter which one I chose? > Actually, I recommend that you first look at the existing saa7127.c source. > I don't know how many differences there are between the saa7121 and > saa7127, but perhaps support for the saa7121 can be added there rather than > introducing a new driver. Of course, that only works if the differences are > not too big. The chips appear to be very similar, sharing most of the registers. However, the aforementioned problem still exists with this driver. A driver connecting this sub device must know beforehand that it has to send standard BT.656 video frames with SAV/EAV codes. Daniel -- Dipl.-Math. Daniel Glöckner, emlix GmbH, http://www.emlix.com Fon +49 551 30664-0, Fax -11, Bahnhofsallee 1b, 37081 Göttingen, Germany Geschäftsführung: Dr. Uwe Kracke, Dr. Cord Seele, Ust-IdNr.: DE 205 198 055 Sitz der Gesellschaft: Göttingen, Amtsgericht Göttingen HR B 3160 emlix - your embedded linux partner