From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH v2 1/4] ARM: dts: omap5: Update GPIO with address space and interrupts Date: Tue, 23 Oct 2012 10:59:06 -0500 Message-ID: <5086BECA.9070502@ti.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5086B316.6000001@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Benoit Cousson Cc: Sebastien Guiriec , Tony Lindgren , devicetree-discuss@lists.ozlabs.org, linux-omap@vger.kernel.org, Santosh Shilimkar , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org 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