From: Mark Kettenis <mark.kettenis@xs4all.nl>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: robh@kernel.org, krzysztof.kozlowski@linaro.org, arnd@arndb.de,
lee@kernel.org, linus.walleij@linaro.org, alyssa@rosenzweig.io,
asahi@lists.linux.dev, brgl@bgdev.pl, marcan@marcan.st,
linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
sven@svenpeter.dev, krzysztof.kozlowski+dt@linaro.org,
devicetree@vger.kernel.org
Subject: Re: [PATCH 1/6] dt-bindings: mfd: add binding for Apple Mac System Management Controller
Date: Tue, 6 Sep 2022 11:31:17 +0200 (CEST) [thread overview]
Message-ID: <d3cecee5edd24f67@bloch.sibelius.xs4all.nl> (raw)
In-Reply-To: <YxcNLU+KGEolrdfT@shell.armlinux.org.uk>
> Date: Tue, 6 Sep 2022 10:04:45 +0100
> From: "Russell King (Oracle)" <linux@armlinux.org.uk>
>
> On Fri, Sep 02, 2022 at 12:28:08PM -0500, Rob Herring wrote:
> > This one is actually pretty odd in that the child nodes don't have a
> > compatible string which breaks the automagical probing.
>
> I don't think that is necessarily true, and I don't think it's true in
> this case.
>
> The SMC core driver instructs the MFD core to create devices for the
> individual functional items:
>
> static const struct mfd_cell apple_smc_devs[] = {
> {
> .name = "macsmc-gpio",
> },
> {
> .name = "macsmc-hid",
> },
> {
> .name = "macsmc-power",
> },
> {
> .name = "macsmc-reboot",
> },
> {
> .name = "macsmc-rtc",
> },
> };
>
> Since MFD uses platform devices for these, they get all the normal
> functionality that these devices have, which include matching by
> device name ot the driver name, and udev events being appropriately
> triggered. As long as the platform drivers for these devices have the
> correct modalias lines, autoloading of the modules will work and the
> drivers will be correctly matched and probed.
>
> The Asahi kernel builds most of the platform support as modules,
> including these, so we know it works (if it didn't, then lots of
> module autoloading would be broken on non-DT platforms.)
>
> > > Again the separate nodes are there because the RTC and the reboot
> > > functionality are logically separate and handled by different MFD
> > > sub-drivers in Linux.
> >
> > It's really a question of whether the subset of functionality is going
> > to get reused on its own or has its own resources in DT. MFD bindings
> > are done both ways.
>
> I think the current position on what to do about these is that everyone
> is looking for someone else to make a decision, and no one wants to!
>
> Firstly, I don't think that the number of properties in a node should
> have a bearing on the design of the DT binding - what should have a
> bearing is the logical partitioning of functionality.
>
> Mark suggests that it would take six months for OpenBSD to transition to
> some other description - for example, if we merged the nodes.
Note that we're totally willing to do that if there is a good
technical reason for changes to the binding. We just have to find a
way to upgrade existing installations of OpenBSD 7.1 which is a bit of
a challenge as the SMC GPIOs are essential for wifi which on the
laptops is the only network connection available.
> Hector says that MacOS's firmware description has the nodes merged, but
> their description is a mess.
To elaborate on that a bit more, the use of sub-nodes provides a nice
separation between the SMC hardware interface (the main node) and the
functionality offered by the firmware running on the SMC (the sub-nodes).
Another argument for having sub-nodes is that the firmware actually
exposes *two* GPIO controllers. For now we only support the "master"
PMU GPIOs, but there also is a "slave" PMU GPIO controller that uses a
separate set of SMC "keys". We currently don't need any of the pins
on the "slave", so we don't expose it in the DT yet.
> The overall preference seems to be to keep the sub-nodes unless there
> is a strong technical reason not to.
>
> The feeling I am getting from the review is that there doesn't seem to
> be a strong technical reason to merge the nodes - there are desires and
> preferences, but nothing concrete.
>
> So at this point, I think it would make sense if I post a v2 with all
> the updates so far (sorry, given the long drawn out discussions on
> this, I've lost track of what changes have been made to the code, so
> I won't include a detailed change log.)
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
>
>
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next prev parent reply other threads:[~2022-09-06 9:32 UTC|newest]
Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 13:54 [PATCH 0/6] Add Apple Mac System Management Controller GPIOs Russell King (Oracle)
2022-09-01 13:54 ` [PATCH 1/6] dt-bindings: mfd: add binding for Apple Mac System Management Controller Russell King (Oracle)
2022-09-01 15:06 ` Krzysztof Kozlowski
2022-09-01 15:12 ` Russell King (Oracle)
2022-09-01 15:15 ` Krzysztof Kozlowski
2022-09-01 15:24 ` Russell King (Oracle)
2022-09-01 15:45 ` Krzysztof Kozlowski
2022-09-01 15:56 ` Russell King (Oracle)
2022-09-01 16:25 ` Krzysztof Kozlowski
2022-09-01 16:47 ` Russell King (Oracle)
2022-09-01 22:33 ` Rob Herring
2022-09-02 15:06 ` Mark Kettenis
2022-09-02 17:28 ` Rob Herring
2022-09-05 10:24 ` Russell King (Oracle)
2022-09-06 9:04 ` Russell King (Oracle)
2022-09-06 9:31 ` Mark Kettenis [this message]
2022-09-06 11:22 ` Linus Walleij
2022-09-06 11:36 ` Hector Martin
2022-09-06 11:57 ` Linus Walleij
2022-09-06 13:28 ` Hector Martin
2022-09-06 13:43 ` Russell King (Oracle)
2022-09-06 13:53 ` Hector Martin
2022-09-06 14:25 ` Mark Kettenis
2022-09-06 14:54 ` Russell King (Oracle)
2022-09-06 15:38 ` Mark Kettenis
2022-09-06 15:55 ` Rob Herring
2022-09-06 13:46 ` Linus Walleij
2022-09-06 15:34 ` Rob Herring
2022-09-06 16:10 ` Rob Herring
2022-09-06 17:00 ` Hector Martin
2022-09-06 17:35 ` Rob Herring
2022-09-06 17:40 ` Sven Peter
2022-09-06 18:38 ` Hector Martin
2022-09-07 9:39 ` Mark Kettenis
2022-09-01 22:26 ` Rob Herring
2022-09-02 14:49 ` Mark Kettenis
2022-09-02 17:04 ` Rob Herring
2022-09-01 19:14 ` Rob Herring
2022-09-01 13:54 ` [PATCH 2/6] dt-bindings: gpio: add binding for the GPIO block for Apple Mac SMC Russell King (Oracle)
2022-09-01 15:11 ` Krzysztof Kozlowski
2022-09-01 15:14 ` Russell King (Oracle)
2022-09-01 13:54 ` [PATCH 3/6] soc: apple: rtkit: Add apple_rtkit_poll Russell King
2022-09-01 17:00 ` Sven Peter
2022-09-01 17:25 ` Eric Curtin
2022-09-01 13:54 ` [PATCH 4/6] platform/apple: Add new Apple Mac SMC driver Russell King
2022-09-01 17:50 ` Sven Peter
2022-09-05 10:55 ` Russell King (Oracle)
2022-09-05 16:53 ` Hector Martin
2022-09-01 19:26 ` Andy Shevchenko
2022-09-02 6:45 ` Sven Peter
2022-09-05 14:45 ` Hector Martin
2022-09-05 15:00 ` Andy Shevchenko
2022-09-08 10:58 ` Lee Jones
2022-09-08 11:28 ` Hector Martin
2022-09-08 12:31 ` Lee Jones
2022-09-08 12:58 ` Hector Martin
2022-09-08 13:29 ` Linus Walleij
2022-09-08 13:36 ` Lee Jones
2022-09-08 13:58 ` Hector Martin
2022-09-09 7:50 ` Lee Jones
2022-09-12 10:03 ` Russell King (Oracle)
2022-09-12 10:55 ` Lee Jones
2022-10-28 15:36 ` Russell King (Oracle)
2022-10-31 8:46 ` Lee Jones
2022-10-31 9:03 ` Hector Martin
2022-10-31 9:44 ` Russell King (Oracle)
2022-10-31 17:24 ` Lee Jones
2022-10-31 19:47 ` Russell King (Oracle)
2022-11-01 9:59 ` Lee Jones
2022-10-29 6:40 ` Hector Martin
2022-10-31 8:48 ` Lee Jones
2022-10-31 8:58 ` Hector Martin
2022-10-31 9:29 ` Lee Jones
2022-10-31 9:44 ` Hector Martin
2022-10-31 17:23 ` Lee Jones
2022-10-31 19:34 ` Russell King (Oracle)
2022-11-02 13:12 ` Lee Jones
2022-11-02 15:54 ` Russell King (Oracle)
2022-09-01 13:54 ` [PATCH 5/6] gpio: Add new gpio-macsmc driver for Apple Macs Russell King
2022-09-01 18:55 ` Andy Shevchenko
2022-09-01 21:51 ` Martin Povišer
2022-09-02 6:31 ` Andy Shevchenko
[not found] ` <3B649A66-8116-432D-B88A-B5CE493EF930@cutebit.org>
[not found] ` <CAHp75VeB3_sZ2vsSxMSsLeJSkyemDh9iOPHXJCN1mhodA13LNQ@mail.gmail.com>
2022-09-02 11:12 ` Martin Povišer
2022-09-02 13:33 ` Andy Shevchenko
2022-09-02 13:36 ` Andy Shevchenko
2022-09-02 13:37 ` Martin Povišer
2022-09-02 14:41 ` Andy Shevchenko
2022-09-02 14:45 ` Russell King (Oracle)
2022-09-02 10:05 ` Russell King (Oracle)
2022-09-02 10:37 ` Andy Shevchenko
2022-09-02 11:32 ` Russell King (Oracle)
2022-09-02 13:39 ` Andy Shevchenko
2022-09-02 14:46 ` Russell King (Oracle)
2022-09-02 14:53 ` Andy Shevchenko
2022-09-02 15:34 ` Russell King (Oracle)
2022-09-02 15:43 ` Andy Shevchenko
2022-09-05 10:20 ` Russell King (Oracle)
2022-09-05 10:32 ` Andy Shevchenko
2022-09-05 13:10 ` Russell King (Oracle)
2022-09-05 13:16 ` Andy Shevchenko
2022-09-05 14:01 ` Russell King (Oracle)
2022-09-05 14:02 ` Russell King (Oracle)
2022-09-05 14:42 ` Andy Shevchenko
2022-09-05 14:53 ` Russell King (Oracle)
2022-09-05 14:50 ` Andy Shevchenko
2022-09-05 15:52 ` Hector Martin
2022-09-05 15:56 ` Russell King (Oracle)
2022-09-05 15:32 ` Russell King (Oracle)
2022-09-05 15:44 ` Martin Povišer
2022-09-05 15:58 ` Hector Martin
2022-09-05 16:13 ` Russell King (Oracle)
2022-09-05 19:10 ` Linus Walleij
2022-09-06 6:51 ` Hector Martin
2022-09-05 15:47 ` Hector Martin
2022-09-05 15:39 ` Hector Martin
2022-09-05 15:16 ` Hector Martin
2022-09-05 15:04 ` Hector Martin
2022-09-02 9:42 ` Linus Walleij
2022-09-01 13:54 ` [PATCH 6/6] gpio: macsmc: Add IRQ support Russell King
2022-09-01 18:03 ` Andy Shevchenko
2022-09-05 11:54 ` Russell King (Oracle)
[not found] ` <CAHp75VeDGCp8J6wnmCqGpV++vs2Zur9Mfp71Dk8dVXcuHFnCrQ@mail.gmail.com>
2022-09-05 13:21 ` Andy Shevchenko
2022-09-02 13:21 ` Linus Walleij
2022-09-05 12:47 ` Russell King (Oracle)
2022-09-05 13:19 ` Fwd: " Andy Shevchenko
2022-09-05 21:43 ` Russell King (Oracle)
2022-09-05 13:27 ` Linus Walleij
2022-09-06 7:00 ` Hector Martin
2022-09-06 7:47 ` Russell King (Oracle)
2022-09-06 8:00 ` Hector Martin
2022-09-01 15:12 ` [PATCH 0/6] Add Apple Mac System Management Controller GPIOs Krzysztof Kozlowski
2022-10-27 15:35 ` Russell King (Oracle)
2022-11-08 16:32 ` [PATCH v3 0/7] " Russell King (Oracle)
2022-11-08 16:33 ` [PATCH v3 1/7] mfd: Add core Apple Mac SMC driver Russell King
2022-11-14 9:52 ` Lee Jones
2022-11-14 10:35 ` Andy Shevchenko
2022-11-08 16:33 ` [PATCH v3 2/7] lib/vsprintf: Add support for generic FOURCCs by extending %p4cc Russell King
2022-11-14 15:34 ` Petr Mladek
2022-11-14 15:46 ` Andy Shevchenko
2022-11-14 16:18 ` Petr Mladek
2022-11-14 16:15 ` Russell King (Oracle)
2022-11-14 16:46 ` Russell King (Oracle)
2022-11-22 12:43 ` Petr Mladek
2022-11-22 14:49 ` Petr Mladek
2022-11-08 16:33 ` [PATCH v3 3/7] dt-bindings: mfd: add binding for Apple Mac System Management Controller Russell King (Oracle)
2022-11-08 20:42 ` Linus Walleij
2022-11-08 20:55 ` Krzysztof Kozlowski
2022-11-08 22:22 ` Russell King (Oracle)
2022-11-09 8:35 ` Krzysztof Kozlowski
2022-11-09 22:17 ` Rob Herring
2022-11-10 11:35 ` Hector Martin
2022-11-10 11:48 ` Russell King (Oracle)
2022-11-10 14:00 ` Krzysztof Kozlowski
2022-11-10 14:14 ` Russell King (Oracle)
2022-11-10 14:21 ` Krzysztof Kozlowski
2022-11-10 14:23 ` Russell King (Oracle)
2022-11-10 14:36 ` Krzysztof Kozlowski
2022-11-10 14:43 ` Russell King (Oracle)
2022-11-14 10:05 ` Lee Jones
2022-11-08 22:30 ` Rob Herring
2022-11-08 16:33 ` [PATCH v3 4/7] platform/apple: Add new Apple Mac SMC driver Russell King
2022-11-08 16:33 ` [PATCH v3 5/7] arm64: dts: apple: Add SMC node to t8103 devicetrees Russell King
2022-11-08 16:33 ` [PATCH v3 6/7] dt-bindings: gpio: add binding for the GPIO block for Apple Mac SMC Russell King (Oracle)
2022-11-08 20:56 ` Krzysztof Kozlowski
2022-11-08 22:09 ` Russell King (Oracle)
2022-11-09 7:31 ` Hector Martin
2022-11-09 8:36 ` Krzysztof Kozlowski
2022-11-09 9:12 ` Russell King (Oracle)
2022-11-09 9:19 ` Krzysztof Kozlowski
2022-11-08 22:30 ` Rob Herring
2022-11-08 16:33 ` [PATCH v3 7/7] gpio: Add new gpio-macsmc driver for Apple Macs Russell King
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