From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932597AbcGDPXZ (ORCPT ); Mon, 4 Jul 2016 11:23:25 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:41570 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752844AbcGDPXW (ORCPT ); Mon, 4 Jul 2016 11:23:22 -0400 Date: Mon, 4 Jul 2016 17:22:26 +0200 From: Mark Brown To: frowand.list@gmail.com Cc: robh+dt@kernel.org, david@gibson.dropbear.id.au, pantelis.antoniou@konsulko.com, stephen.boyd@linaro.org, grant.likely@secretlab.ca, mark.rutland@arm.com, mporter@konsulko.com, koen@dominion.thruhere.net, linux@roeck-us.net, marex@denx.de, wsa@the-dreams.de, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, panto@antoniou-consulting.com Message-ID: <20160704152226.GJ6247@sirena.org.uk> References: <1467503750-31703-1-git-send-email-frowand.list@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5N2+S1LJ+nNsdJJZ" Content-Disposition: inline In-Reply-To: <1467503750-31703-1-git-send-email-frowand.list@gmail.com> X-Cookie: You are always busy. User-Agent: Mutt/1.6.0 (2016-04-01) X-SA-Exim-Connect-IP: 137.158.22.87 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [RFC PATCH 0/1] Portable Device Tree Connector -- conceptual X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --5N2+S1LJ+nNsdJJZ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Jul 02, 2016 at 04:55:49PM -0700, frowand.list@gmail.com wrote: > This is an extremely simple example to illustrate the concepts. It is not > meant to represent the complexity of a real board. >=20 > To start with, assume that the device that will eventually be on a daught= er > board is first soldered onto the mother board. The mother board contains > two devices connected via bus spi_1. One device is described in the .dts > file, the other is described in an included .dtsi file. > Then the device tree files will look like: Can I suggest not using SPI as an example here? It's particularly messy since addresses are essentially just a random signal that can be totally separate to the controller hardware which might be adding more complexity early on in building up your model than is really desirable. It will need to be dealt with but perhaps not right now. I2C might be easier. The initial issue with SPI is that you really need to do something like bring out individual slots on the bus rather than the bus as a whole since you're going to need a remapping layer to map chip selects on the module to chip selects on the host board. --5N2+S1LJ+nNsdJJZ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXen8xAAoJECTWi3JdVIfQaucH/0A83ZrZkJ1ue7mFQAJnOjnP 6EZo3skp4dDpCyM562aF5ktNsR7NmneqCuJYvd9dcjuTuMtc0gOU8CpzPZyIPTwa YMibm+UpnzBoGzz9lL6qKvICD1EuboLPJGbumR99B65avEaMHNUep36BIyztXIQI IhFrjZ/KT7WcmwZgFRsGz3plqFEFecrEFQG0mdM9uuB3uVgyShzB83HFyWcfIWKW xvqBFTNrpxtyRrOrVS05MdHVHmBP80kJLC+xNn3ea48LnwVLI1VhpWZRY/43esbF FeGwLL48XPnIeZw8TDJIdkR4E9l0iclgEINDmFP+XSHNLACz/oPb5Rx/JEb3Y+4= =1Jid -----END PGP SIGNATURE----- --5N2+S1LJ+nNsdJJZ--