From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Cooper Subject: Re: [PATCH v2 2/5] irqchip: Add DT binding doc for dumb demuxer chips Date: Wed, 14 Jan 2015 13:56:19 -0500 Message-ID: <20150114185619.GB24989@titan.lakedaemon.net> References: <1421174781-4340-1-git-send-email-boris.brezillon@free-electrons.com> <1421174781-4340-3-git-send-email-boris.brezillon@free-electrons.com> <20150113190050.GZ24989@titan.lakedaemon.net> <20150113215207.185d92b4@bbrezillon> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20150113215207.185d92b4@bbrezillon> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Boris Brezillon Cc: Thomas Gleixner , Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , "Rafael J. Wysocki" , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org Hey Boris, On Tue, Jan 13, 2015 at 09:52:07PM +0100, Boris Brezillon wrote: > On Tue, 13 Jan 2015 14:00:50 -0500 Jason Cooper wrote: > > On Tue, Jan 13, 2015 at 07:46:18PM +0100, Boris Brezillon wrote: > > > Add documentation for the dumb demuxer. > > >=20 > > > Signed-off-by: Boris Brezillon > > > --- > > > .../bindings/interrupt-controller/dumb-demux.txt | 34 ++++++++= ++++++++++++++ > > > 1 file changed, 34 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/interrupt-c= ontroller/dumb-demux.txt > > >=20 > > > diff --git a/Documentation/devicetree/bindings/interrupt-controll= er/dumb-demux.txt b/Documentation/devicetree/bindings/interrupt-control= ler/dumb-demux.txt > > > new file mode 100644 > > > index 0000000..1c777ef > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/interrupt-controller/dumb= -demux.txt > > > @@ -0,0 +1,34 @@ > > > +* Generic Dumb Interrupt Demultiplexer > > > + > > > +This Dumb demultiplixer simply forward all incoming interrupts t= o its > > > +enabled/unmasked children. > >=20 > > Please forgive the potentially na=EFve question, but what hardware = is this > > describing? >=20 > That's not a real hardware per se, but on some hardware (like at91 So= Cs) > some IRQ line are shared by several peripherals, and this dumb > demultiplex is here to represent such shared irq lines which cannot b= e > easily demultiplexed (because they do not provide a 'cause' > register). >=20 > You can see it as a virtual irqchip provided to address broken hardwa= re > designs. Hmm. Well, given tglx's recent reply, I suppose I'll *not* go down the rabbit hole of "the DT is for describing hardware." :-P However, it would probably be a lot more palatable to the DT maintainer= s if we at least change the compatible to prepend "linux,". This way, if someone does come up with a better solution down the road, it will be much easier to deprecate the binding. I would also be amenable to "virt,", or "hack,", or even "work-around-piss-poor-hw,". Basically, anything that would indicate t= o consumers of the DT that this is not a true reflection of the hardware, and that it may be superseded by a better solution later. It would also be helpful to explain the situation more fully in the binding document. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html