From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v5 4/5] media: ov5640: add support of DVP parallel interface Date: Mon, 5 Feb 2018 14:56:38 +0100 Message-ID: <20180205135638.vkuotmeks5k76iud@flea> References: <1514973452-10464-1-git-send-email-hugues.fruchet@st.com> <1514973452-10464-5-git-send-email-hugues.fruchet@st.com> <20180202185045.vvhmj5wtagalkucf@flea.lan> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ilbt4aunkczvniud" Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Fabrizio Castro Cc: Hugues Fruchet , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Benjamin Gaignard , Ramesh Shanmugasundaram , Chris Paterson , Hans Verkuil , Sakari Ailus , Steve Longerbeam , Mauro Carvalho Chehab , Mark Rutland , Rob Herring List-Id: devicetree@vger.kernel.org --ilbt4aunkczvniud Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 05, 2018 at 11:42:11AM +0000, Fabrizio Castro wrote: > Hello Maxime, >=20 > thank you for your feedback. >=20 > > > > +/* > > > > + * configure parallel port control lines polarity > > > > + * > > > > + * POLARITY CTRL0 > > > > + * - [5]:PCLK polarity (0: active low, 1: active high) > > > > + * - [1]:HREF polarity (0: active low, 1: active high) > > > > + * - [0]:VSYNC polarity (mismatch here between > > > > + *datasheet and hardware, 0 is active high > > > > + *and 1 is active low...) > > > > > > I know that yourself and Maxime have both confirmed that VSYNC > > > polarity is inverted, but I am looking at HSYNC and VSYNC with a > > > logic analyser and I am dumping the values written to > > > OV5640_REG_POLARITY_CTRL00 and to me it looks like that HSYNC is > > > active HIGH when hsync_pol =3D=3D 0, and VSYNC is active HIGH when > > > vsync_pol =3D=3D 1. > > > > Which mode are you testing this on? >=20 > My testing environment is made of the sensor connected to a SoC with > 8 data lines, vsync, hsync, and pclk, and of course I am specifying > hsync-active, vsync-active, and pclk-sample in the device tree on > both ends so that they configure themselves accordingly to work in > DVP mode (V4L2_MBUS_PARALLEL), with the correct polarities. > > Between the sensor and the SoC there is a noninverting bus > transceiver (voltage translator), for my experiments I have plugged > myself onto the outputs of this transceiver only to be compliant > with the voltage level of my logic analyser. Sorry, my question was more about the resolution, refresh rate, etc. > > The non-active periods are insanely high in most modes (1896 for an > > active horizontal length of 640 in 640x480 for example), especially > > hsync, and it's really easy to invert the two. >=20 > I am looking at all the data lines, so that I don't confuse the > non-active periods with the active periods, and with my setup what I > reported is what I get. I wonder if this difference comes from the > sensor revision at all? Unfortunately I can only test the one camera > I have got. I don't really know then. I've had issues with the polarities on my side, but it was on the receiver side and the sensor part looked like what is documented. Maxime --=20 Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering http://bootlin.com --ilbt4aunkczvniud Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlp4YpUACgkQ0rTAlCFN r3TIWw//aGZ5MjQRoWi1F753l0C6BMtobEx8utifF5v9IRwekB3R/TIjllXdXwXO Ev4qj21YrO1SjanFk6UTccJ/tqa9v0/cLJ9LCOc1Og+psBJgSBOtDVUyV8U7lTrf 8Ta9YtZmEBuLb8CHPcRKZozkBta3E23wO8xD3nGnLKN0In5knglZFmGgJTNbzAlM 5vCmBOBXeflcYWY2CpqAAbR86cNGPaPDI5KZLGysPHEBOU66CdJ1ykUOSEGtJJhV Q2O4NqbbL2Xm80woP34EGgNvov7etZuorvQbdhVTbRWsP8cMPkcSWpSJLxjSNpf/ qe5L1fQwjZqNmVGXq5ZIJKUDUumH3hGWHWgnQCvaImU17aXeR9UUG8djhNdxNP3v syxUNzszOrC63zjSqPXTDNx/UzDtTbXKakal9kKByW1ijFeaL1LVNj6M04BljA1J 51Rl+7wGTxTSm4bD1qUcmmbi8rkaF2rxN6IInZ4urp9ACuuFTy1+P7F9TnEsM+70 GOvxqvX9vL4ZZV3q6qi6GyfATiQLmD5gDLodwvpAfrI3xr3qctalThzg0NsaEKU6 xCRlpDm/fm2W5ch4fqSUsXfbcmGSEM6JXXFTcBrdP72GcTwyAbH7xbjc4fXimoU3 1XpdEMTCENFSX6XBANExQLmZlYlJsKB8RvOvm5WjXt4e+DP9yFM= =wUfz -----END PGP SIGNATURE----- --ilbt4aunkczvniud-- -- 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