Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751941AbdH1SUY (ORCPT ); Mon, 28 Aug 2017 14:20:24 -0400 Received: from mail-wr0-f194.google.com ([209.85.128.194]:35562 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751258AbdH1SUU (ORCPT ); Mon, 28 Aug 2017 14:20:20 -0400 Subject: Re: [PATCH] nokia n900: update dts with camera support To: Sakari Ailus , Pavel Machek Cc: Sebastian Reichel , pali.rohar@gmail.com, kernel list , linux-arm-kernel , linux-omap@vger.kernel.org, tony@atomide.com, khilman@kernel.org, aaro.koskinen@iki.fi, patrikbachan@gmail.com, serge@hallyn.com, abcloriens@gmail.com References: <20170810204923.GA18442@amd> <20170814201950.sbtyuksn3ntuigyp@valkosipuli.retiisi.org.uk> <20170815220349.GA15441@amd> <20170816205332.rqcuenvuxfs5jvuw@earth> <20170816205915.GA5386@atrey.karlin.mff.cuni.cz> <20170816212343.hfd4azb4dq2qrlkc@valkosipuli.retiisi.org.uk> <20170817000845.agkcuvqaheejm33j@earth> <20170828135959.GA32560@amd> <20170828150725.nvrr2c3a2lir5xic@valkosipuli.retiisi.org.uk> From: Ivaylo Dimitrov Message-ID: Date: Mon, 28 Aug 2017 21:20:14 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170828150725.nvrr2c3a2lir5xic@valkosipuli.retiisi.org.uk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1883 Lines: 54 Hi On 28.08.2017 18:07, Sakari Ailus wrote: > Hi Pavel, > > On Mon, Aug 28, 2017 at 03:59:59PM +0200, Pavel Machek wrote: >> Hi! >> >>>>> Well, strobe property above already uses = <0>/<1> format, as do >>>>> others. >>>> >>>>> Problem with "false = property does not exist" is that you don't know >>>>> if it is "someone forgot to define it" or "someone made a typo" or >>>>> "dts is too old to know about this property" or "the property indeed >>>>> should be false"... >>>> >>>> As this is an established practice, I think we should follow it for bool >>>> properties. >>> >>> Yes it's common practice, there is also device_property_read_bool() >>> to get the value. >>> >>>> We could change the existing ones, too, and leave some extra checks in >>>> place to handle old dtbs. >>> >>> The following should be downward compatible: >>> >>> var = read_bool(); >>> if (var && !read_int()) >>> var = false; >>> >>> Btw. DT people should be CC'd for DT binding additions/changes. >> >> Ok, so for now we do crc=1 by default. Now we'd like to have crc >> support configurable in the dts. But if we just introduce "crc;" >> option, it will break old dts users. We could introduce "no-crc;" and >> that would work in this particular case, but will break when we want >> different defaults at different devices. >> >> Anyway, introducing "no-crc;" seems pretty ugly to me. I'd rather do >> "crc=<0>;", in a similar way we handle other options now. > > The same issue actually exists for CSI-2: the CRC is typically enabled and > I think you can at least disable the check (in OMAP3 ISP). Do we have a > need to disable it at the moment for any purpose? I think I've seen this > was disabled somewhere but it may just as well be a thoughtlessly written > configuration. > Front camera has crc disabled in Nokia kernel. I am not sure the sensor supports crc at all. Regards, Ivo