Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932938Ab2JWP7Q (ORCPT ); Tue, 23 Oct 2012 11:59:16 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:57601 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751745Ab2JWP7P (ORCPT ); Tue, 23 Oct 2012 11:59:15 -0400 Message-ID: <5086BECA.9070502@ti.com> Date: Tue, 23 Oct 2012 10:59:06 -0500 From: Jon Hunter User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Benoit Cousson CC: Sebastien Guiriec , Tony Lindgren , , , Santosh Shilimkar , , Subject: Re: [PATCH v2 1/4] ARM: dts: omap5: Update GPIO with address space and interrupts References: <1350981432-6750-1-git-send-email-s-guiriec@ti.com> <1350981432-6750-2-git-send-email-s-guiriec@ti.com> <5086AE8E.60106@ti.com> <5086B316.6000001@ti.com> In-Reply-To: <5086B316.6000001@ti.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [192.157.144.139] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2543 Lines: 64 On 10/23/2012 10:09 AM, Benoit Cousson wrote: > On 10/23/2012 04:49 PM, Jon Hunter wrote: >> Hi Seb, >> >> On 10/23/2012 03:37 AM, Sebastien Guiriec wrote: >>> Add base address and interrupt line inside Device Tree data for >>> OMAP5 >>> >>> Signed-off-by: Sebastien Guiriec >>> --- >>> arch/arm/boot/dts/omap5.dtsi | 16 ++++++++++++++++ >>> 1 file changed, 16 insertions(+) >>> >>> diff --git a/arch/arm/boot/dts/omap5.dtsi b/arch/arm/boot/dts/omap5.dtsi >>> index 42c78be..9e39f9f 100644 >>> --- a/arch/arm/boot/dts/omap5.dtsi >>> +++ b/arch/arm/boot/dts/omap5.dtsi >>> @@ -104,6 +104,8 @@ >>> >>> gpio1: gpio@4ae10000 { >>> compatible = "ti,omap4-gpio"; >>> + reg = <0x4ae10000 0x200>; >>> + interrupts = <0 29 0x4>; >>> ti,hwmods = "gpio1"; >>> gpio-controller; >>> #gpio-cells = <2>; >> >> I am wondering if we should add the "interrupt-parent" property to add >> nodes in the device-tree source. I know that today the interrupt-parent >> is being defined globally, but when device-tree maps an interrupt for a >> device it searches for the interrupt-parent starting the current device >> node. >> >> So in other words, for gpio1 it will search the gpio1 binding for >> "interrupt-parent" and if not found move up a level and search again. It >> will keep doing this until it finds the "interrupt-parent". >> >> Therefore, I believe it will improve search time and hence, boot time if >> we have interrupt-parent defined in each node. > > Mmm, I'm not that sure. it will increase the size of the blob, so > increase the time to load it and then to parse it. Where in the current > case, it is just going up to the parent node using the already > un-flatten tree in memory and thus that should not take that much time. Yes it will definitely increase the size, so that could slow things down. > That being said, it might be interesting to benchmark that to see what > is the real impact. Right, I wonder what the key functions are we need to benchmark to get an overall feel for what is best? Right now I am seeing some people add the interrupt-parent for device nodes and others not. Ideally we should be consistent, but at the same time it is probably something that we can easily sort out later. So not a big deal either way. Cheers Jon -- 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/