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From: Saravana Kannan <saravanak@google.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	linux-tegra <linux-tegra@vger.kernel.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Jon Hunter <jonathanh@nvidia.com>,
	Android Kernel Team <kernel-team@android.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] of: property: Add fw_devlink support for "gpio" and "gpios" binding
Date: Tue, 19 Jan 2021 09:53:53 -0800	[thread overview]
Message-ID: <CAGETcx-Vp0BpYbpPjwsmOv0q5ba1mJvfsPEZ9Oi2Rmx67udu7A@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdZqSm-xfo8a8aFUe-Mbaw9tM+OmCAF3KWjOVDfC=oWj+Q@mail.gmail.com>

On Tue, Jan 19, 2021 at 2:20 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Tue, Jan 19, 2021 at 9:50 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> > > Can we pull this into driver-core-next please? It fixes issues on some
> > > boards with fw_devlink=on.
> >
> > On r8a77951-salvator-xs.dts, it introduces one more failure:
> >
> >     OF: /soc/i2c@e66d8000/gpio@20/pcie-sata-switch-hog: could not get
> > #gpio-cells for /cpus/cpu@102

Geert,

One good thing is that it's noticing this being weird and ignoring it
in your particular board. I *think* it interprets the "7" as a phandle
and that's cpu@102 and realizes it's not a gpio-controller. For at
least in your case, it's a safe failure.

> >
> > Seems like it doesn't parse gpios properties in GPIO hogs correctly.
>
> Could it be that the code assumes no self-referencing phandles?
> (Just guessing...)
>

Linus,

Ok I tried to understand what gpio-hogs means. It's not fully clear to
me. But it looks like if a gpio-controller has a gpio-hog, then it
doesn't have/need gpio-cells? Is that right?

So if a gpio-controller has a gpio-hog, can it ever be referred to by
another consumer in DT using blah-gpios = ...? If so, I don't see any
obvious code that's handling the missing gpio-cells in this case.

Long story short, please help me understand gpio-hog in the context of
finding dependencies in DT.

Thanks,
Saravana

  parent reply	other threads:[~2021-01-19 19:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-15 21:01 [PATCH v1] of: property: Add fw_devlink support for "gpio" and "gpios" binding Saravana Kannan
2021-01-18 15:32 ` Linus Walleij
2021-01-18 22:11   ` Saravana Kannan
2021-01-19  8:50     ` Geert Uytterhoeven
2021-01-19 10:20       ` Linus Walleij
2021-01-19 17:52         ` Thierry Reding
2021-01-19 17:53         ` Saravana Kannan [this message]
2021-01-19 18:10           ` Geert Uytterhoeven
2021-01-19 18:18             ` Saravana Kannan
2021-01-19 18:32               ` Geert Uytterhoeven
2021-01-19 18:47                 ` Saravana Kannan

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