From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 0/5] media: Allwinner A10 CSI support Date: Thu, 15 Nov 2018 20:10:31 +0100 Message-ID: <20181115191031.7jpb2g23fksof625@flea> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="i7rh5slrqsdzymby" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Chen-Yu Tsai Cc: Hans Verkuil , Sakari Ailus , Mauro Carvalho Chehab , Thomas Petazzoni , Laurent Pinchart , Linux Media Mailing List , Andrzej Hajda , linux-kernel , linux-arm-kernel , devicetree , Mark Rutland , Rob Herring , Frank Rowand List-Id: devicetree@vger.kernel.org --i7rh5slrqsdzymby Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Wed, Nov 14, 2018 at 11:24:48AM +0800, Chen-Yu Tsai wrote: > On Tue, Nov 13, 2018 at 4:24 PM Maxime Ripard = wrote: > > Here is a series introducing the support for the A10 (and SoCs of the s= ame > > generation) CMOS Sensor Interface (called CSI, not to be confused with > > MIPI-CSI, which isn't support by that IP). > > > > That interface is pretty straightforward, but the driver has a few issu= es > > that I wanted to bring up: > > > > * The only board I've been testing this with has an ov5640 sensor > > attached, which doesn't work with the upstream driver. Copying the > > Allwinner init sequence works though, and this is how it has been > > tested. Testing with a second sensor would allow to see if it's an > > issue on the CSI side or the sensor side. > > * When starting a capture, the last buffer to capture will fail due to > > double buffering being used, and we don't have a next buffer for the > > last frame. I'm not sure how to deal with that though. It seems like > > some drivers use a scratch buffer in such a case, some don't care, = so > > I'm not sure which solution should be preferred. > > * We don't have support for the ISP at the moment, but this can be ad= ded > > eventually. > > > > * How to model the CSI module clock isn't really clear to me. It looks > > like it goes through the CSI controller and then is muxed to one of= the > > CSI pin so that it can clock the sensor. I'm not quite sure how to > > model it, if it should be a clock, the CSI driver being a clock > > provider, or if the sensor should just use the module clock directl= y. >=20 > Which clock are you talking about? MCLK? This seems to be fed directly fr= om > the CCU, as there doesn't seem to be controls for it within the CSI hardw= are > block, and the diagram doesn't list it either. IMO you don't have to mode= l it. > The camera sensor device node would just take a reference to it directly. Yeah, that what I went for, I guess we agree :) > You would probably enable the (separate) pinmux setting in the CSI > controller node. I'll change that. Thanks! Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --i7rh5slrqsdzymby Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCW+3EpwAKCRDj7w1vZxhR xay5AP0YIuMeE90TQHjAJ1bmsn3H3GyD9S7o46GGYjpDWeiDVAEA0LfACvVkvr4a UO4k+2DcRSF8um3oE1z73dhuaKYkJwk= =1sff -----END PGP SIGNATURE----- --i7rh5slrqsdzymby--