From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: [RFC PATCH] [media]: of: move graph helpers from drivers/media/v4l2-core to drivers/of Date: Mon, 10 Mar 2014 12:18:20 +0200 Message-ID: <531D916C.2010903@ti.com> References: <1392119105-25298-1-git-send-email-p.zabel@pengutronix.de> < CAL_Jsq+U9zU1i+STLHMBjY5BeEP6djYnJVE5X1ix-D2q_zWztQ@mail.gmail.com> < 20140217181451.7EB7FC4044D@trevor.secretlab.ca> <20140218070624.GP17250@ pengutronix.de> <20140218162627.32BA4C40517@trevor.secretlab.ca> < 1393263389.3091.82.camel@pizza.hi.pengutronix.de> <20140226110114. CF2C7C40A89@trevor.secretlab.ca> <1393426129.3248.64.camel@paszta.hi. pengutronix.de> <20140307170550.1DFB2C40A0D@trevor.secretlab.ca> <531AF1E8. 50606@ti.com> <20140308114115.BB08EC40612@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="m9agE5FH5X00TA97e9K7BvgiWLaTKpLWn" Return-path: In-Reply-To: <20140308114115.BB08EC40612@trevor.secretlab.ca> Sender: linux-media-owner@vger.kernel.org To: Grant Likely , Philipp Zabel Cc: Sascha Hauer , Rob Herring , Russell King - ARM Linux , Mauro Carvalho Chehab , Rob Herring , Sylwester Nawrocki , Laurent Pinchart , Kyungmin Park , "linux-kernel@vger.kernel.org" , "linux-media@vger.kernel.org" , "devicetree@vger.kernel.org" , Philipp Zabel List-Id: devicetree@vger.kernel.org --m9agE5FH5X00TA97e9K7BvgiWLaTKpLWn Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 08/03/14 13:41, Grant Likely wrote: >> Ok. If we go for single directional link, the question is then: which >> way? And is the direction different for display and camera, which are >> kind of reflections of each other? >=20 > In general I would recommend choosing whichever device you would > sensibly think of as a master. In the camera case I would choose the > camera controller node instead of the camera itself, and in the display= > case I would choose the display controller instead of the panel. The > binding author needs to choose what she things makes the most sense, bu= t > drivers can still use if it it turns out to be 'backwards' I would perhaps choose the same approach, but at the same time I think it's all but clear. The display controller doesn't control the panel any more than a DMA controller controls, say, the display controller. In fact, in earlier versions of OMAP DSS DT support I had a simpler port description, and in that I had the panel as the master (i.e. link from panel to dispc) because the panel driver uses the display controller's features to provide the panel device a data stream. And even with the current OMAP DSS DT version, which uses the v4l2 style ports/endpoints, the driver model is still the same, and only links towards upstream are used. So one reason I'm happy with the dual-linking is that I can easily follow the links from the downstream entities to upstream entities, and other people, who have different driver model, can easily do the opposite= =2E But I agree that single-linking is enough and this can be handled at runtime, even if it makes the code more complex. And perhaps requires extra data in the dts, to give the start points for the graph. Tomi --m9agE5FH5X00TA97e9K7BvgiWLaTKpLWn Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTHZFsAAoJEPo9qoy8lh71TxgP/2VBc8qqL7gzkimED+kI2e+J tDApeGiLcqQEq7MW+Jgq9ssDxPUUY/zoIDEM2xzg1xO9fXVi++TziIXEGrp0vE/r JAYUT/YQ+St07VakXFrnBPAmvpIfph+mE841yr0gOXVyY+EJKFWK8RUwCCLBL6WJ jBTuy7gHUQpTcm+Y+gI2rUh12buP8i9kSaqTmI2qIEtV08GmDvQJm5d6u9uGKHk1 kbzuV9IT3/3W2iBiiphIfjdeZ5n+qwxUbPNVy+fdzf8z9+mCl7cqwIQGV1fIdRK1 wapu+JGFoqc36PdtGUiTImJDfkoInPfuyj2IEhEKzTSV2sDM2XYn0g0HNwuKvIro E9CEQXeqm2G0TUbmtxNPWgHGXu7GOkHa5PhfzYyQIBBoX3hQrS12bRkrsb3gmMM6 tAMZQU/6Jkwjwl0qXXI8tH4p6nvxQbLIXxzkhpbv7Qh4Ue32C6AkD3I1zL043dCr N2qeWdNz7rVHRL0EFXnJQoem0n70R6SToCXreJiH4NWg9uiTcm1Ey0dc8Dc07cST ZV4Wxky+zDvnAIKXI7Aa26yHIdJXZPMIsr4carehvRfoLZVtoCoT4Fg7MnUDf2sz n91XgkSLqlPkzRcSiLf87DAzhuFEtGBE1tvYq924wGr6cPVGIt0ELPNKBofaMzra yQGD/2hoPCNBi/DVj9BW =leqH -----END PGP SIGNATURE----- --m9agE5FH5X00TA97e9K7BvgiWLaTKpLWn--