From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752689AbaFDLTD (ORCPT ); Wed, 4 Jun 2014 07:19:03 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:52982 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752538AbaFDLTA (ORCPT ); Wed, 4 Jun 2014 07:19:00 -0400 Date: Wed, 4 Jun 2014 12:17:55 +0100 From: Mark Brown To: Marcel Ziswiler Cc: Stephen Warren , thierry.reding@gmail.com, linux@arm.linux.org.uk, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, stefan@agner.ch Message-ID: <20140604111755.GG2520@sirena.org.uk> References: <39a8704a4c8170d6b0620a1e5e44042eae6d8810.1401665237.git.marcel@ziswiler.com> <538CA24B.1010602@wwwdotorg.org> <538CA635.4050502@ziswiler.com> <20140602221627.GP31751@sirena.org.uk> <538D64FD.2010909@ziswiler.com> <20140603094537.GQ31751@sirena.org.uk> <538EBACB.70100@ziswiler.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Fnm8lRGFTVS/3GuM" Content-Disposition: inline In-Reply-To: <538EBACB.70100@ziswiler.com> X-Cookie: Your lucky color has faded. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 109.148.252.180 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH 2/3] arm: tegra: enable igb, stmpe, i2c chardev, spidev, lm95245, pwm leds 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 --Fnm8lRGFTVS/3GuM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jun 04, 2014 at 08:20:59AM +0200, Marcel Ziswiler wrote: > On 06/03/2014 11:45 AM, Mark Brown wrote: > >When you say "generic user space access" you are describing a specific > >detail of how this device happens to be controlled with your software. > No, not at all. In fact I did not even specify neither the exact type of > device apart from it being a SPI device nor any property of the software > apart from the generic user space access thereof implemented in the Linux You're saying you're controlling it from userspace. This is a particular detail of what you are doing in your system. You happen to want to control the devices you are hanging off the system with userspace drivers but that's just what you're doing right now. > kernel. I really don't see any difference to i2c chardev which is already > enabled in multi_v7_defconfig. That does not require explicit registration as the device driver for the device in order to be used. > >This is not a description of your hardware, it is a description of how > >it is controlled with your current software. > Sorry, but I really don't know what you are referring to. It's a pure > hardware description of some pins being the SPI bus namely MISO/MOSI and the > clock plus an accompanying chip-select pin. No, that's in the controller node - the chip selects are described there. The child node references a chip select number that the master has and describes what's connected to that chip select. > I fear for some reason or another you have some affinity against spidev > which strikes me odd. Admittedly it is not perfect but it is the only > generic SPI user space access currently implemented in the Linux kernel and > so far did its job perfectly for many of our customers. It's a perfectly fine way of controlling things from userspace if that's a sensible way of controlling devices but that does not mean you should describe it in the device tree in that fashion. --Fnm8lRGFTVS/3GuM Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJTjwBfAAoJELSic+t+oim9g0kP/21/0pU2F2LXOmH3xpr0/hkV emJkq4yant0EYn3b2iG3DJS6LKVu4rXKnV/TyHeAHjJnxROGA1284YlZdiTxasxd Fucib/fvMQVFnEIiyMmwhb/RLQbd7Ieui8ViTP0o7hmA43ZKZ/G0yIMWXAVE3Uck Te7w5qrgZXsEg6/s+w/j79SqGCeBwlY/8A2dQzdsgn76FPbDrHuqrVEz/SOKwPoz 7OcPsWYSaesjLq2uU0Amt/hDp13WgEZvO2F6CQXaQMlbxP2eVao0ayA8ElS+G4g4 4ZDyw6wLwooXIuJiTh07la7PP9JmmZw8ymTdRI/tgG8Y4Qoyfk1GMAosFmIhBWFw o/71CJSil4OkuOJO7bvHBF2ei7l9ZksB+J1ZaIXju/oUelM4I3bT7HRysmmmNvCE aleTkdpKFJVxwfvYeeHkE8BYb9BAcMmdjkA1Lspq4PAiXsqODzwdIFkakVwc/SRS QH0eIpiaVggSuIH3F/eYE55jaBPSlJtMGrR5JyKIJpA1CYc3JILWir6BW3SWNzJ5 0dvYpWEeaP5SulTNiRk+EpZQ2LB0tpImF7aE1xVMLjFm06X89amqzgnCFuV7MAT8 KPogyqmoJmW2Nxcl+Jo3vcQzk8bMQhOqxeEh6dKOewL6bsDxMjJabDvYWqWD5X5B 2JUWUObJXL1Hz3UB75oi =6UGA -----END PGP SIGNATURE----- --Fnm8lRGFTVS/3GuM--