Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934874AbdGTIiw (ORCPT ); Thu, 20 Jul 2017 04:38:52 -0400 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.162]:34289 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933179AbdGTIir (ORCPT ); Thu, 20 Jul 2017 04:38:47 -0400 X-RZG-AUTH: :JGIXVUS7cutRB/49FwqZ7WcecEarQROEYabkiUo6mSAGQ+qKIDgoI8ZYkQ== 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] Add support of OV9655 camera From: "H. Nikolaus Schaller" In-Reply-To: <20170718195223.zrqfrefxxzqfsojd@valkosipuli.retiisi.org.uk> Date: Thu, 20 Jul 2017 10:37:58 +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> <2dd3402e-55b0-231d-878f-5ba95ee8cb36@st.com> <20170718195223.zrqfrefxxzqfsojd@valkosipuli.retiisi.org.uk> To: Sakari Ailus , 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 v6K8cwuj003788 Content-Length: 3644 Lines: 86 Hi, > Am 18.07.2017 um 21:52 schrieb Sakari Ailus : > > On Tue, Jul 18, 2017 at 12:53:12PM +0000, Hugues FRUCHET wrote: >> >> >> On 07/18/2017 02:17 PM, H. Nikolaus Schaller wrote: >>> 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 >>> >> >> As Sylwester and Hans, I'm also in flavour of a separate driver, the >> fact that register set seems similar but in fact is not and that we >> cannot test for non-regression of 9650/52 are killer for me to continue >> on a single driver. >> We can now restart from a new fresh state of the art sensor driver >> getting rid of legacy (pdata, old gpio, etc...). > > Agreed. I bet the result will look cleaner indeed although this wasn't one > of the complex drivers. I finally managed to find the bug why mplayer did select-timeout on the GTA04. Was a bug in pinmux setup of the GTA04 for the omap3isp. And I have resurrected our years old 3.12 camera driver, which was based on the MT9P031 code. It was already separate from ov9650/52. I have extended it to support DT by including some parts of Hugues' work. It still needs some cleanup and discussion but will be a simple patch (one for ov9655.c + Kconfig + Makefile) and one for bindings (I hope it includes all your comments). I will post v1 in the next days. BR, Nikolaus