From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: Re: [PATCH V2 03/19] irqchip: crossbar: Skip some irqs from getting mapped to crossbar Date: Fri, 13 Jun 2014 09:35:20 -0400 Message-ID: <539AFE18.3020706@ti.com> References: <1402574007-13987-1-git-send-email-r.sricharan@ti.com> <1402574007-13987-4-git-send-email-r.sricharan@ti.com> <20140612125134.GS8664@titan.lakedaemon.net> <20140612135715.GE17845@atomide.com> <20140612140508.GC8664@titan.lakedaemon.net> <539AA08A.7010001@ti.com> <20140613131005.GF8664@titan.lakedaemon.net> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140613131005.GF8664-u4khhh1J0LxI1Ri9qeTfzeTW4wlIGRCZ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Cooper , Sricharan R Cc: Tony Lindgren , linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, nm-l0cyMroinI0@public.gmane.org, rnayak-l0cyMroinI0@public.gmane.org, linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org List-Id: devicetree@vger.kernel.org On Friday 13 June 2014 09:10 AM, Jason Cooper wrote: > On Fri, Jun 13, 2014 at 12:26:10PM +0530, Sricharan R wrote: >> On Thursday 12 June 2014 07:35 PM, Jason Cooper wrote: > ... >>> Do you have other changes outside of irqchip depending on this series? >>> If so, I can set up a topic branch for you guys to base off of. >>> Otherwise, I'll just apply them to irqchip/core when they're ready. >>> >> There are dts changes which are dependent upon this series. >> >> http://www.spinics.net/lists/linux-omap/msg108116.html > > In general, dts changes shouldn't depend on code changes or vice-versa. > If they do, that's an indicator that we're breaking compatibility with > older dtbs. > Thats true. The case with cross-bar though is the feature wasn't completly supported so far before this series. Perhaps the the initial bindings should have been marked unstable. > Looking at the dra7.dtsi changes, we're redefining the interrupt > property, which can't be good. :( > > Perhaps a better solution would be to add a property, say 'ti,cross-irq' > that is the exact same format as 'interrupts', but is used by the > crossbar driver? > We have gone over those earlier and it was agreed to re-use interrupt properties and for special cases, define a cross-bar property to describe it. > I'm not convinced of this yet, I suspect we may not actually have a > dependency between the dtsi changes and the code changes. We would have > the ugly "if you have the crossbar node, 'interrupts' means X, if not it > means Y" in the binding docs. But the absence of the node prevents the > crossbar driver from re-interpreting the interrupts property. > In ideal cross-bar hardware you don't need the assumption "if you have the crossbar node, 'interrupts' means X, if not it means Y" It is purely because the cross-bar irq router hardware has few nasty bugs which needs those special handling. And thats the reason, the property was added. > Have you tried booting all the different scenarios? eg: > > old dtb, new driver > new dtb, old driver > old dtb, old driver > new dtb, new driver > Old driver wasn't complete as mentioned and hence the above combinations becomes bit irrelevant. Regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html