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From: Rob Herring <robh+dt@kernel.org>
To: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	"devicetree-spec@vger.kernel.org"
	<devicetree-spec@vger.kernel.org>
Subject: Re: [RFC/PATCH v4 1/4] Document nexus nodes/specifier remapping
Date: Mon, 18 Sep 2017 12:44:38 -0500	[thread overview]
Message-ID: <CAL_Jsq+qRm=iAhQz6Ro3SAU45JEK8KNWpRBcXuRt47r8ncYYwQ@mail.gmail.com> (raw)
In-Reply-To: <20170811154236.12891-2-stephen.boyd@linaro.org>

On Fri, Aug 11, 2017 at 10:42 AM, Stephen Boyd <stephen.boyd@linaro.org> wrote:
> Document the generic nexus node properties. This can be used by
> any specifier that conforms to #<specifier>-cells where they
> want to support remapping phandle lists through nexus nodes. This
> is similar to interrupt remapping, but slightly different because
> we don't consider unit addresses when doing mappings. This is
> mostly a copy/paste of the interrupt specification, with the unit
> address parts removed and generalized to any specifier. There's
> also the addition of a pass through mechanism to make things more
> compact if desired in the mapping table.

Sorry for the slow response.

I'm still wondering how/if we can merge interrupts as part of this
(both the spec and parsing implementation). Could we simply require
that #address-cells is 0 or do we even need this distinction? If the
usecase is connectors, then we should typically be able to set
#address-cells to 0. Perhaps you could have a custom PCI connector
with additional signals and the slot/connector node would have the PCI
address. In this case, we would have #address-cells, but having them
and ignoring the address cells via the mask would still work.

Also, I don't see any issue if we allow the -map-pass-thru property
for interrupts.

>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
>
> I still need to write the blurb about what this is all about, but
> I wanted to send this out now to get early feedback. Some starting
> points:
>
>  1) Replace child/parent with incoming/outgoing everywhere?

Parent/child is more common, so I think that's fine.

>
>  2) Make a pretty picture to describe remapping phandle+specifiers
>     similar to the interrupt hierarchy diagram?

Pictures are always nice, but I don't think required.

>
>  3) Come up with some better name than <specifier>? Kernel-doc uses <list>
>     but I'm not sure that's any better.

specifier seems fine to me.

Rob

  reply	other threads:[~2017-09-18 17:44 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-11 15:42 [PATCH v4 0/4] OF phandle nexus support + GPIO nexus Stephen Boyd
2017-08-11 15:42 ` [RFC/PATCH v4 1/4] Document nexus nodes/specifier remapping Stephen Boyd
2017-09-18 17:44   ` Rob Herring [this message]
2017-08-11 15:42 ` [PATCH v4 2/4] of: Support parsing phandle argument lists through a nexus node Stephen Boyd
2017-08-11 15:42 ` [PATCH v4 3/4] of: unittest: Add phandle remapping test Stephen Boyd
     [not found] ` <20170811154236.12891-1-stephen.boyd-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-08-11 15:42   ` [PATCH v4 4/4] gpio: Support gpio nexus dt bindings Stephen Boyd
2017-08-15 20:36   ` [PATCH v4 0/4] OF phandle nexus support + GPIO nexus Rob Herring

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