From: Conor Dooley <conor@kernel.org>
To: Tudor Ambarus <tudor.ambarus@linaro.org>
Cc: Conor Dooley <conor.dooley@microchip.com>,
Jassi Brar <jassisinghbrar@gmail.com>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-samsung-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, andre.draszik@linaro.org,
peter.griffin@linaro.org, kernel-team@android.com,
willmcvicker@google.com, daniel.lezcano@linaro.org,
vincent.guittot@linaro.org, ulf.hansson@linaro.org,
arnd@arndb.de
Subject: Re: [PATCH 1/2] dt-bindings: mailbox: add support for referencing controllers solely by node
Date: Fri, 20 Dec 2024 19:41:57 +0000 [thread overview]
Message-ID: <20241220-carving-diagram-a27c04aafb10@spud> (raw)
In-Reply-To: <463d5955-a056-40e1-a46e-f89ac0dadccf@linaro.org>
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On Fri, Dec 20, 2024 at 07:51:32AM +0000, Tudor Ambarus wrote:
>
>
> On 12/19/24 6:58 PM, Conor Dooley wrote:
> > On Thu, Dec 19, 2024 at 03:42:11PM +0000, Tudor Ambarus wrote:
> >> Hi, Conor,
> >>
> >> On 12/19/24 2:11 PM, Conor Dooley wrote:
> >>>> There are mailbox clients that can discover the mailbox channel ID at
> >>>> run-time. For such cases passing the channel identifier via DT is
> >>>> redundant. Add support for referencing controllers solely by node.
> >>> I don't really get your implementation, why not just allow #mbox-cells = 0?
> >>> That's what's done for things like fixed frequency clocks that only have
> >>> a single output.
> >>
> >> Ah, indeed!
> >>
> >> instead of:
> >> of_parse_phandle(dev->of_node, "mbox", 0);
> >> I can do a:
> >> of_parse_phandle_with_args(dev->of_node, "mboxes",
> >> "#mbox-cells", 0, &of_args)
> >> where #mbox-cells = 0;
> >>
> >> Or ... can I pass NULL for cells_name and make the #mbox-cells property
> >> optional and still keeping its requirement of being at least 1?
> >
> > I think the mbox-cells = 0 approach is preferred, that property is what
> > marks it as a mailbox controller after all. Perhaps Rob or Krzysztof can
> > comment?
>
> I think using mbox-cells = 0 is better indeed. In my proposal I
> considered the list to always have a single phandle, thus a reference to
> a single mailbox controller, whereas it may be possible that clients to
> reference multiple mailbox controllers. If so, #mbox-cells needs to be
> defined in all the controllers, for consistency reasons, similar to what
> happens with fixed clocks, as you already mentioned.
Oh right, I had totally forgotten about that, that's a solid argument
for the mbox-cells = 0 approach for sure.
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next prev parent reply other threads:[~2024-12-20 19:43 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-19 13:07 [PATCH 0/2] mailbox: add support for clients to request channels by arguments Tudor Ambarus
2024-12-19 13:07 ` [PATCH 1/2] dt-bindings: mailbox: add support for referencing controllers solely by node Tudor Ambarus
2024-12-19 14:11 ` Conor Dooley
2024-12-19 15:42 ` Tudor Ambarus
2024-12-19 18:58 ` Conor Dooley
2024-12-20 7:51 ` Tudor Ambarus
2024-12-20 19:41 ` Conor Dooley [this message]
2024-12-19 13:07 ` [PATCH 2/2] mailbox: add support for clients to request channels by arguments Tudor Ambarus
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