Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751564AbdFGWT5 (ORCPT ); Wed, 7 Jun 2017 18:19:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:57064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751422AbdFGWTz (ORCPT ); Wed, 7 Jun 2017 18:19:55 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C477239AC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=robh+dt@kernel.org MIME-Version: 1.0 In-Reply-To: <1496823091.28265.3.camel@hp800z> References: <1496667567-13266-1-git-send-email-stefani.seibold.ext@huawei.com> <1496688186.12947.10.camel@hp800z> <1496776664.3821.3.camel@seibold.net> <1496823091.28265.3.camel@hp800z> From: Rob Herring Date: Wed, 7 Jun 2017 17:19:33 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] external references for device tree overlays To: Pantelis Antoniou Cc: Stefani Seibold , Stefani Seibold , Frank Rowand , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Holm Rauchfuss Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2200 Lines: 79 On Wed, Jun 7, 2017 at 3:11 AM, Pantelis Antoniou wrote: > Hi Stefani, > > On Tue, 2017-06-06 at 21:17 +0200, Stefani Seibold wrote: >> Hi Pantelis, >> >> thanks for the suggestion. This feature is not very well documented. I >> tried this on my rasp1 running 4.12.0-rc3 and it doesn't work. My >> source is: >> >> // rapsi example >> /dts-v1/; >> /plugin/; >> >> / { >> compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709"; >> >> fragment@0 { >> target-path = "/soc/i2s@7e203000"; >> __overlay__ { >> #address-cells = <0x00000001>; >> #size-cells = <0x00000001>; >> test = "test"; >> timer = <&{/soc/timer@7e0030000}>; >> }; >> }; >> }; >> >> >> The resulting overlay is (decompiled with fdtdump): >> >> /dts-v1/; >> // magic: 0xd00dfeed >> // totalsize: 0x19a (410) >> // off_dt_struct: 0x38 >> // off_dt_strings: 0x148 >> // off_mem_rsvmap: 0x28 >> // version: 17 >> // last_comp_version: 16 >> // boot_cpuid_phys: 0x0 >> // size_dt_strings: 0x52 >> // size_dt_struct: 0x110 >> >> / { >> compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709"; >> fragment@0 { >> target-path = "/soc/i2s@7e203000"; >> __overlay__ { >> #address-cells = <0x00000001>; >> #size-cells = <0x00000001>; >> test = "test"; >> timer = <0xdeadbeef>; >> }; >> }; >> __fixups__ { >> /soc/timer@7e0030000 = "/fragment@0/__overlay__:timer:0"; >> }; >> }; >> >> But this will not apply: >> >> OF: resolver: overlay phandle fixup failed: -22 >> create_overlay: Failed to resolve tree >> >> > > Yes, it will not work as it is; my point is that you don't need the > magic __*__ node. > > You will need to modify the overlay application code to live insert a > phandle (if it doesn't exist) when it encounters a /path fixup. phandles only exist if something in the base tree refers to that node. Adding them when they don't exist should definitely be something we support for overlays. But don't call that a broken DT. That would be a separate issue. Rob