Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751434AbdGRMxu (ORCPT ); Tue, 18 Jul 2017 08:53:50 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:6340 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751371AbdGRMxs (ORCPT ); Tue, 18 Jul 2017 08:53:48 -0400 From: Hugues FRUCHET To: "H. Nikolaus Schaller" , Sylwester Nawrocki , Hans Verkuil 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" Subject: Re: [PATCH v2 0/7] [PATCH v2 0/7] Add support of OV9655 camera Thread-Topic: [PATCH v2 0/7] [PATCH v2 0/7] Add support of OV9655 camera Thread-Index: AQHS890Jv/3Hvsb23UGHm/yJrpLIDKJQii+AgAjnUoCAAATsAIAACfGA Date: Tue, 18 Jul 2017 12:53:12 +0000 Message-ID: <2dd3402e-55b0-231d-878f-5ba95ee8cb36@st.com> 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> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.50] Content-Type: text/plain; charset="utf-8" Content-ID: <0606AD7205958C4DB8FD3950C939896E@st.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-18_04:,, signatures=0 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 base64 to 8bit by nfs id v6ICrtRF002836 Content-Length: 2703 Lines: 63 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...). BR, Hugues.