Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751423AbdGRMSd (ORCPT ); Tue, 18 Jul 2017 08:18:33 -0400 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.160]:20976 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751322AbdGRMSb (ORCPT ); Tue, 18 Jul 2017 08:18:31 -0400 X-RZG-AUTH: :JGIXVUS7cutRB/49FwqZ7WcecEarQROEYabkiUo6mSAGQ+qKID80POGb4jk= X-RZG-CLASS-ID: mo00 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: [PATCH v2 0/7] [PATCH v2 0/7] Add support of OV9655 camera From: "H. Nikolaus Schaller" In-Reply-To: <956f17e6-36dd-6733-0d35-9b801ed4244d@xs4all.nl> Date: Tue, 18 Jul 2017 14:17:36 +0200 Cc: Guennadi Liakhovetski , Rob Herring , Mark Rutland , Maxime Coquelin , Alexandre Torgue , Mauro Carvalho Chehab , devicetree , LKML , Yannick Fertre , Benjamin Gaignard , linux-arm-kernel , linux-media@vger.kernel.org Message-Id: References: <1499073368-31905-1-git-send-email-hugues.fruchet@st.com> <8157da84-1484-8375-1f2b-9831973915b4@kernel.org> <956f17e6-36dd-6733-0d35-9b801ed4244d@xs4all.nl> To: Hugues Fruchet , Sylwester Nawrocki , Hans Verkuil X-Mailer: Apple Mail (2.3124) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6ICIaSo031611 Content-Length: 2235 Lines: 50 Hi, > Am 18.07.2017 um 13:59 schrieb Hans Verkuil : > > On 12/07/17 22:01, Sylwester Nawrocki wrote: >> Hi Hugues, >> >> On 07/03/2017 11:16 AM, Hugues Fruchet wrote: >>> This patchset enables OV9655 camera support. >>> >>> OV9655 support has been tested using STM32F4DIS-CAM extension board >>> plugged on connector P1 of STM32F746G-DISCO board. >>> Due to lack of OV9650/52 hardware support, the modified related code >>> could not have been checked for non-regression. >>> >>> First patches upgrade current support of OV9650/52 to prepare then >>> introduction of OV9655 variant patch. >>> Because of OV9655 register set slightly different from OV9650/9652, >>> not all of the driver features are supported (controls). Supported >>> resolutions are limited to VGA, QVGA, QQVGA. >>> Supported format is limited to RGB565. >>> Controls are limited to color bar test pattern for test purpose. >> >> I appreciate your efforts towards making a common driver but IMO it would be >> better to create a separate driver for the OV9655 sensor. The original driver >> is 1576 lines of code, your patch set adds half of that (816). There are >> significant differences in the feature set of both sensors, there are >> differences in the register layout. I would go for a separate driver, we >> would then have code easier to follow and wouldn't need to worry about possible >> regressions. I'm afraid I have lost the camera module and won't be able >> to test the patch set against regressions. >> >> IMHO from maintenance POV it's better to make a separate driver. In the end >> of the day we wouldn't be adding much more code than it is being done now. > > I agree. We do not have great experiences in the past with trying to support > multiple variants in a single driver (unless the diffs are truly small). Well, IMHO the diffs in ov965x are smaller (but untestable because nobody seems to have an ov9650/52 board) than within the bq27xxx chips, but I can dig out an old pdata based separate ov9655 driver and extend that to become DT compatible. I had abandoned that separate approach in favour of extending the ov965x driver. Have to discuss with Hugues how to proceed. BR and thanks, Nikolaus