Re: [PATCH v2 18/23] dt-bindings: thermal: armada: add reference to new bindings

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Rob Herring <robh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>, Andrew Lunn <andrew@lunn.ch>,
	Jason Cooper <jason@lakedaemon.net>,
	Nadav Haklai <nadavh@marvell.com>,
	devicetree@vger.kernel.org,
	Antoine Tenart <antoine.tenart@bootlin.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Gregory CLEMENT <gregory.clement@bootlin.com>,
	"open list:THERMAL" <linux-pm@vger.kernel.org>,
	Will Deacon <will.deacon@arm.com>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	Eduardo Valentin <edubezval@gmail.com>,
	David Sniatkiwicz <davidsn@marvell.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Zhang Rui <rui.zhang@intel.com>,
	"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
	<linux-arm-kernel@lists.infradead.org>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH v2 18/23] dt-bindings: thermal: armada: add reference to new bindings
Date: Mon, 16 Jul 2018 16:32:26 +0200	[thread overview]
Message-ID: <20180716163226.6f532579@xps13> (raw)
In-Reply-To: <CAL_JsqLG6vDmyH3X7aHUUMRC+BN3orC5T8iHYUHHZVsQ6rM0Tg@mail.gmail.com>

Hi Rob,

> > > > > > for AP806 and CP110 compatibles. Add a reference to these files from the
> > > > > > original documentation.
> > > > > >
> > > > > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > > > > > ---
> > > > > >  Documentation/devicetree/bindings/thermal/armada-thermal.txt | 5 +++++
> > > > > >  1 file changed, 5 insertions(+)
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/thermal/armada-thermal.txt b/Documentation/devicetree/bindings/thermal/armada-thermal.txt
> > > > > > index e0d013a2e66d..f3b441100890 100644
> > > > > > --- a/Documentation/devicetree/bindings/thermal/armada-thermal.txt
> > > > > > +++ b/Documentation/devicetree/bindings/thermal/armada-thermal.txt
> > > > > > @@ -10,6 +10,11 @@ Required properties:
> > > > > >      * marvell,armada-ap806-thermal
> > > > > >      * marvell,armada-cp110-thermal  
> > > > >
> > > > > Really you should not be using the same compatible for both. Now you
> > > > > have 2 drivers matching to same compatibles.
> > > > >
> > > > > Can't you make this a child of the syscon without breaking the binding?  
> > > >
> > > > We are talking about only 1 driver here, so I'm not sure how I should
> > > > understand your last sentence. Do you want me to add a second
> > > > compatible (for the same piece of hardware) for thermal node declared
> > > > as a child of the syscon?  
> > >
> > > I don't know what I'm suggesting. Your changes look like they break
> > > compatibility to me.  
> >
> > There is code in the driver to handle the legacy non-syscon-ish thermal
> > node ("armada_thermal_probe_legacy()"). An old DT with a new kernel
> > would work fine.  
> 
> Okay, that's good.
> 
> > > What happens if you use this new binding without any kernel change?  
> >
> > I suppose you mean "during the merge window"? In this case the driver
> > of the thermal IP will not probe (and spawn an error in the dmesg) with
> > ap806/cp110 IPs. As the support is pretty new for them, this is maybe
> > not a huge issue. Also, before the DT changes adding thermal zones,
> > just retrieving the temperature might be pretty useless. However, it
> > is always possible to merge the driver changes in 4.19 and the DT
> > changes in 4.20.  
> 
> Not the merge window, but distros (SUSE at least) want to be able to
> boot with current DTs and their distro (old) kernel. Maybe for this
> platform you don't care.

Indeed, I think we don't care that much for this platform.

Let me resend the series with the 'interrupt' reference removed as I
think it was the last thing to address.

Thanks,
Miquèl

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