Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752607AbbERONb (ORCPT ); Mon, 18 May 2015 10:13:31 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:33235 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751048AbbERON2 convert rfc822-to-8bit (ORCPT ); Mon, 18 May 2015 10:13:28 -0400 Subject: Re: [PATCH/RFC] kbuild: Create a rule for building device tree overlay objects Mime-Version: 1.0 (Mac OS X Mail 8.2 $2098$) Content-Type: text/plain; charset=utf-8 From: Pantelis Antoniou In-Reply-To: <5556A893.9060204@gmail.com> Date: Mon, 18 May 2015 17:13:21 +0300 Cc: Geert Uytterhoeven , linux-kbuild@vger.kernel.org, devicetree , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: <2FE8B176-8A95-457C-A9B9-D089FC525E6A@gmail.com> References: <1431431816-24612-1-git-send-email-geert+renesas@glider.be> <555693AA.1000105@gmail.com> <5556A893.9060204@gmail.com> To: frowand.list@gmail.com X-Mailer: Apple Mail (2.2098) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2908 Lines: 87 Hi Frank, > On May 16, 2015, at 05:16 , Frank Rowand wrote: > > On 5/15/2015 5:47 PM, Frank Rowand wrote: >> On 5/12/2015 7:33 AM, Pantelis Antoniou wrote: >>> Hi Geert, >>> >>>> On May 12, 2015, at 14:56 , Geert Uytterhoeven wrote: >>>> >>>> This allows to handle device tree overlays like plain device trees. >>>> >>>> Signed-off-by: Geert Uytterhoeven >>>> --- >>>> Questions: >>>> - Do we want dtso files under arch//boot/dts/, too? >>>> - Do we want to move the dts files outside the kernel repository >>>> first? >>>> >>> >>> Oh that’s a nice hornet’s nest you’ve kicked here. >>> >>> arch//boot/dts should not be the place, cause overlays are not related with boot per se. >>> As they are right now are board (family) specific. >> >> Aren't overlays meant to describe child boards (capes, shields, whatever) that may >> vary from system to system, but are not expected to be hot-plugged while the OS >> is up? Or is hot-plug a design goal? > > To reply to myself, there is a current discussion about whether to use overlays to > help with a powerpc pci desire to add and delete subtrees: > > http://www.spinics.net/lists/linux-pci/msg40740.html > > That sound like hot-plug to me… > Many people asked for overlays with hot-plugging probably busses like PCI and USB. Think about an FPGA on a PCI board that needs to be instantiated after insertion. Expect more activity on that particular front; probably this week. >> >> If no hot-plug, then to me an overlay is just as related to boot as the base dts. >> It is a mere implementation detail that overlays are "loaded" from userspace >> instead of by the booting kernel (I don't really know the details of using >> overlays, so please correct me if I am wrong about how the kernel becomes aware >> of an overlay). >> >>> >>> I think we should try to keep an external kernel repo with them for now until we >>> figure out where to put them. >>> >>>> scripts/Makefile.lib | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib >>>> index 79e86613712f2230..4b14eef1d4b2ce8f 100644 >>>> --- a/scripts/Makefile.lib >>>> +++ b/scripts/Makefile.lib >>>> @@ -292,6 +292,9 @@ cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \ >>>> $(obj)/%.dtb: $(src)/%.dts FORCE >>>> $(call if_changed_dep,dtc) >>>> >>>> +$(obj)/%.dtbo: $(src)/%.dtso FORCE >>>> + $(call if_changed_dep,dtc) >>>> + >>>> dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp) >>>> >>>> # Bzip2 >>>> -- >>>> 1.9.1 >>> >>> Regards >>> >>> — Pantelis Regards — Pantelis -- 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/