Re: [PATCH] regulator: fan53555: add back tcs4526

From: Mark Brown <broonie@kernel.org>
To: Peter Geis <pgwipeout@gmail.com>
Cc: Rudi Heitbaum <rudi@heitbaum.com>,
	devicetree@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	Ezequiel Garcia <ezequiel@collabora.com>,
	chenjh@rock-chips.com
Subject: Re: [PATCH] regulator: fan53555: add back tcs4526
Date: Thu, 27 May 2021 14:03:32 +0100	[thread overview]
Message-ID: <YK+YpBm9M2GbFGec@sirena.org.uk> (raw)
In-Reply-To: <CAMdYzYq8c4=D6_LxG2jPfbtPkOp5tN8oRA0zKt_OM6HLbnfFTw@mail.gmail.com>

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On Thu, May 27, 2021 at 07:26:01AM -0400, Peter Geis wrote:
> On Thu, May 27, 2021 at 6:59 AM Rudi Heitbaum <rudi@heitbaum.com> wrote:

> > > Since you aren't adding any functional code, is there a particular
> > > reason you can't just add the chip id and simply use the tcs4525
> > > compatible?
> > > This will prevent you from needing to modify the dt-bindings as well.

..

> > I chose to follow the example of silergy,syr827 and silergy,syr828 for
> > tcs4526 (given I made the mistake in assuming that support for tcs4525
> > meant support for tcs4525.) This would maintain consistency of naming of
> > tcs4526 throughout the source. Is that ok?

> It's fine to have both compatibles (and avoids confusion in
> device-trees), just remember to update the dt-bindings as well.
> It's funny to see drivers with both schemes, so we really have to
> decide which path we want to go down.
> Considering the syr827/syr828 as convention, we should probably just
> go down that route for consistency within the driver.

It is generally safer for the DT to be explicit about exactly
what the hardware is and then double check that this matches the
actual hardware, this gives more room for handling things with
quirks if needed in future and makes the life of people writing
DTs for boards easier since they don't need to remap part
numbers from the schematic to the DT.

> > +&gpu {
> > +       mali-supply = <&vdd_gpu>;
> > +       assigned-clocks = <&cru ACLK_GPU>;
> > +       assigned-clock-rates = <200000000>;
> > +       status = "okay";
> > +       /delete-property/ operating-points-v2;

> Removal of the operating points kind of makes the gpu regulator moot,
> don't you think?

It's still better to say what the supply is even if it can't be
changed - that stops you getting warnings about substituting in a
dummy regulator and allows the consumer to read the current state
of the regulator in case that's useful.

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