Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753771Ab2ELInO (ORCPT ); Sat, 12 May 2012 04:43:14 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:48407 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751475Ab2ELInI convert rfc822-to-8bit (ORCPT ); Sat, 12 May 2012 04:43:08 -0400 MIME-Version: 1.0 In-Reply-To: References: <1335935266-25289-1-git-send-email-thomas.abraham@linaro.org> <1335935266-25289-4-git-send-email-thomas.abraham@linaro.org> Date: Sat, 12 May 2012 14:13:07 +0530 Message-ID: Subject: Re: [PATCH 3/7] mmc: dw_mmc: add device tree support From: Thomas Abraham To: Olof Johansson Cc: linux-mmc@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, cjb@laptop.org, grant.likely@secretlab.ca, rob.herring@calxeda.com, linux-samsung-soc@vger.kernel.org, kgene.kim@samsung.com, patches@linaro.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2242 Lines: 62 On 12 May 2012 12:37, Olof Johansson wrote: > Hi, > > On Thu, May 10, 2012 at 3:15 AM, Thomas Abraham > wrote: >> Hi Olof, >> >> On 2 May 2012 23:37, Olof Johansson wrote: >>> Hi, >> >> [...] >> >>>> +# Slots: The slot specific information are contained within child-nodes with >>>> + ?each child-node representing a supported slot. There should be atleast one >>>> + ?child node representing a card slot. The name of the slot child node should >>>> + ?be 'slot{n}' where n is the unique number of the slot connnected to the >>>> + ?controller. The following are optional properties which can be included in >>>> + ?the slot child node. >>> >>> Since we're talking slots / cards on a bus, I think the addressing >>> model would be useful here. So in the main controller node: >>> ? ?#address-cells = <1>; >>> ? ?#size-cells = <0>; >>> >>> And then each slot would need a reg property and possibly unit address: >>> >>> ? slot { >>> ? ? ? ?reg = <0>; >>> ? ? ? ?... >>> ? }; >>> >>> (unit addresses on the slots are only needed if they can't be >>> disambiguated by name, so not needed if you only have one slot). >>> >> >> Is the addressing model as described above needed in this case? The >> address for a slot is not used by the controller driver code and is >> just a virtual number. It would be sufficient to represent the nodes >> representing the slots with a unique name. > > The driver has the concept of slot IDs (slot->id struct member), and > the hardware definitely enumerates them. > > So, I think it makes sense to give a chance to enumerate the slots in > the device tree. Otherwise, how do you know which one is which on > hardware? It also opens up the flexibility to have the same name for > both slots if it makes sense to describe a board that way. Thanks Olof. Yes, I missed the usage of the id number in the driver. I will add the slot addressing as you have suggested and repost. Thanks, Thomas. > > > -Olof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/