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Subject: Re: [PATCH v4 00/10] clk: Add kunit tests for fixed rate and parent data
From: Stephen Boyd <sboyd@kernel.org>
Cc: David Gow <davidgow@google.com>, Michael Turquette <mturquette@baylibre.com>, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, patches@lists.linux.dev, kunit-dev@googlegroups.com, linux-kselftest@vger.kernel.org, devicetree@vger.kernel.org, Brendan Higgins <brendan.higgins@linux.dev>, Rae Moar <rmoar@google.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Rafael J . Wysocki <rafael@kernel.org>, Saravana Kannan <saravanak@google.com>, Daniel Latypov <dlatypov@google.com>, Christian Marangi <ansuelsmth@gmail.com>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, Maxime Ripard <maxime@cerno.tech>
To: Rob Herring <robh@kernel.org>
Date: Thu, 16 May 2024 17:33:31 -0700
User-Agent: alot/0.10

Quoting Rob Herring (2024-05-15 15:08:47)
> On Wed, May 15, 2024 at 4:15=E2=80=AFPM Stephen Boyd <sboyd@kernel.org> w=
rote:
> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > index 389d4ea6bfc1..acecefcfdba7 100644
> > --- a/drivers/of/platform.c
> > +++ b/drivers/of/platform.c
> > @@ -421,6 +421,7 @@ int of_platform_bus_probe(struct device_node *root,
> >         if (of_match_node(matches, root)) {
> >                 rc =3D of_platform_bus_create(root, matches, NULL, pare=
nt, false);
> >         } else for_each_child_of_node(root, child) {
> > +               of_node_set_flag(root, OF_POPULATED_BUS);
>=20
> No, the same spot as of_platform_populate has it. I guess this would
> be the same, but no reason to do this in the for_each_child_of_node
> loop...

Ok. I'm not intending to send this patch.

>=20
> >                 if (!of_match_node(matches, child))
> >                         continue;
> >                 rc =3D of_platform_bus_create(child, matches, NULL, par=
ent, false);
> >
> >
> > This doesn't work though. I see that prom_init() is called, which
> > constructs a DTB and flattens it to be unflattened by
> > unflatten_device_tree(). The powerpc machine type used by qemu is
> > PLATFORM_PSERIES_LPAR. It looks like it never calls
> > of_platform_bus_probe() from the pseries platform code.
>=20
> Huh. Maybe pseries doesn't have any platform devices?

Looks like it.

>=20
> Ideally, we'd still do it in of_platform_default_populate_init(), but
> if you look at the history, you'll see that broke some PPC boards
> (damn initcall ordering).
>=20
> > What about skipping the OF_POPULATED_BUS check, or skipping the check
> > when the parent is the root node? This is the if condition that's
> > giving the headache.
>=20
> I don't think we should just remove it, but a root node check seems fine.
>=20

Alright. I've added a check to see if the root node is the parent to
allow it. That works well enough, so I'll send that in v5.