From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stewart Smith Subject: Re: [PATCH v2 2/2] leds/powernv: Add driver for PowerNV platform Date: Fri, 24 Apr 2015 14:18:30 +1000 Message-ID: References: <20150422234509.626d9dc7@ja.home> <55388254.4000606@linux.vnet.ibm.com> <20150423161342.55e9ac8f@ja.home> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:42957 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750891AbbDXESf (ORCPT ); Fri, 24 Apr 2015 00:18:35 -0400 Received: from /spool/local by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 23 Apr 2015 22:18:34 -0600 Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 3CEDB1FF0025 for ; Thu, 23 Apr 2015 22:09:43 -0600 (MDT) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t3O4IB5e33882280 for ; Thu, 23 Apr 2015 21:18:11 -0700 Received: from d03av03.boulder.ibm.com (localhost [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t3O4IVu9024775 for ; Thu, 23 Apr 2015 22:18:32 -0600 In-Reply-To: <20150423161342.55e9ac8f@ja.home> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Jacek Anaszewski , Vasant Hegde Cc: linux-leds@vger.kernel.org, cooloney@gmail.com, rpurdie@rpsys.net, linuxppc-dev@lists.ozlabs.org, khandual@linux.vnet.ibm.com Jacek Anaszewski writes: >> These device tree comes from out firmware ... which is immutable . > > How the firmware is related to kernel? These bindings are for kernel, > not for the firmware. > > DT bindings are compiled to *.dtb file which is concatenated with > zImage. During system boot device drivers are matched with DT bindings > through 'compatible' property. A driver should have single matching DT > node, i.e. no other driver can probe with the same DT node. > This implies that the node should contain only the properties required > for configuring the related device. For OPAL firmware on POWER, firmware hands kernel a flattened device tree of the machine it's booting on. It's not added to kernel as the kernels aren't board specific - they're generic. https://github.com/open-power/skiboot/ is the firmware that generates the device tree for booting under OPAL.