From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yong Subject: Re: [PATCH v5 0/5] Add OV5640 parallel interface and RGB565/YUYV support Date: Fri, 12 Jan 2018 10:18:39 +0800 Message-ID: <20180112101839.cc13571a099d64eea2ac6e3a@magewell.com> References: <1514973452-10464-1-git-send-email-hugues.fruchet@st.com> <20180108153811.5xrvbaekm6nxtoa6@flea> <3010811e-ed37-4489-6a9f-6cc835f41575@st.com> <20180110153724.l77zpdgxfbzkznuf@flea> <20180111091508.a0c9f630c6b4ef80178694fb@magewell.com> <20180111124018.azdzjeitjsyenmra@flea.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180111124018.azdzjeitjsyenmra-ZC1Zs529Oq4@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Maxime Ripard Cc: Hugues FRUCHET , Steve Longerbeam , Sakari Ailus , Hans Verkuil , Mauro Carvalho Chehab , Rob Herring , Mark Rutland , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Benjamin Gaignard List-Id: devicetree@vger.kernel.org Hi Maxime, On Thu, 11 Jan 2018 13:40:18 +0100 Maxime Ripard wrote: > Hi Yong, > > On Thu, Jan 11, 2018 at 09:15:08AM +0800, Yong wrote: > > > On Mon, Jan 08, 2018 at 05:13:39PM +0000, Hugues FRUCHET wrote: > > > > I'm using a ST board with OV5640 wired in parallel bus output in order > > > > to interface to my STM32 DCMI parallel interface. > > > > Perhaps could you describe your setup so I could help on understanding > > > > the problem on your side. From my past experience with this sensor > > > > module, you can first check hsync/vsync polarities, the datasheet is > > > > buggy on VSYNC polarity as documented in patch 4/5. > > > > > > It turns out that it was indeed a polarity issue. > > > > > > It looks like that in order to operate properly, I need to setup the > > > opposite polarity on HSYNC and VSYNC on the interface. I looked at the > > > signals under a scope, and VSYNC is obviously inversed as you > > > described. HSYNC, I'm not so sure since the HBLANK period seems very > > > long, almost a line. > > > > > > Since VSYNC at least looks correct, I'd be inclined to think that the > > > polarity is inversed on at least the SoC I'm using it on. > > > > > > Yong, did you test the V3S CSI driver with a parallel interface? With > > > what sensor driver? Have you found some polarities issues like this? > > > > Did you try it with Allwinner SoCs? > > Yes, on an H3. Looking at all the Allwinner datasheet I could get my > hands on, they are all documented in the same way. However, I really > start to wonder whether the polarity shouldn't be reversed. > > At least the fact that VSYNC is clearly active low on the > oscilloscope, while I have to set it active high in the controller > seems like a strong hint :) The BSP code of Allwinner also treat V4L2_MBUS_VSYNC_ACTIVE_HIGH as they documented 'positive'. Maybe there need some more tests to confirm if the datasheet and BSP code are both wrong. > > > No. I only tested with a BT1120 signal generated by FPGA or ADV7611. HSYNC > > and VSYNC are not used. > > Ok, that's good to know :) > > > For V3s CSI driver, I will add the following to dt-bindings: > > Endpoint node properties for CSI1 > > --------------------------------- > > > > - remote-endpoint : (required) a phandle to the bus receiver's endpoint > > node > > - bus-width: : (required) must be 8, 10, 12 or 16 > > - pclk-sample : (optional) (default: sample on falling edge) > > - hsync-active : (only required for parallel) > > - vsync-active : (only required for parallel) > > > > You could try diffrent hsync-active/vsync-active values here. > > I did already, and the only combination that works is the one that is > the inversed polarity on HSYNC and VSYNC than what the sensor setup. > > Maxime > > -- > Maxime Ripard, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com Thanks, Yong -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html