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From: Lucas Stach <l.stach@pengutronix.de>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Fabio Estevam <festevam@gmail.com>,
	Lubomir Rintel <lkundrak@v3.sk>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	DRI mailing list <dri-devel@lists.freedesktop.org>,
	The etnaviv authors <etnaviv@lists.freedesktop.org>,
	Christian Gmeiner <christian.gmeiner@gmail.com>
Subject: Re: [PATCH 2/3] drm/etnaviv: Don't ignore errors on getting clocks
Date: Thu, 14 May 2020 10:40:58 +0200	[thread overview]
Message-ID: <ab384507b90474b0030d8ce64fdcfe868b52c3cb.camel@pengutronix.de> (raw)
In-Reply-To: <20200514082755.GN1551@shell.armlinux.org.uk>

Am Donnerstag, den 14.05.2020, 09:27 +0100 schrieb Russell King - ARM Linux admin:
> On Thu, May 14, 2020 at 10:18:02AM +0200, Lucas Stach wrote:
> > Am Mittwoch, den 13.05.2020, 23:41 -0300 schrieb Fabio Estevam:
> > > On Wed, May 13, 2020 at 2:09 PM Fabio Estevam <festevam@gmail.com> wrote:
> > > 
> > > > The binding doc Documentation/devicetree/bindings/gpu/vivante,gc.yaml
> > > > says that only the 'reg' clock could be optional, the others are
> > > > required.
> > > 
> > > arch/arm/boot/dts/dove.dtsi only uses the 'core' clock.
> > > arch/arm/boot/dts/stm32mp157.dtsi uses 'bus' and 'core'
> > > 
> > > Maybe the binding needs to be updated and it seems that using
> > > devm_clk_get_optional() like you propose is safe.
> > 
> > The binding is correct as-is. We want to require those clocks to be
> > present, but the dove DT was added before the binding was finalized, so
> > the driver still treats the clocks as optional to not break
> > compatibility with old DTs. Maybe this warrants a comment in the
> > code...
> 
> The binding doc in mainline says:
> 
>   clocks:
>     items:
>       - description: AXI/master interface clock
>       - description: GPU core clock
>       - description: Shader clock (only required if GPU has feature PIPE_3D)
>       - description: AHB/slave interface clock (only required if GPU can gate slave interface independently)
>     minItems: 1
>     maxItems: 4
> 
>   clock-names:
>     items:
>       enum: [ bus, core, shader, reg ]
>     minItems: 1
>     maxItems: 4
> 
> which looks correct to me - and means that Dove is compliant with that.

The YAML binding actually did loose something in translation here,
which I didn't notice. Previously all those clocks were listed under
"Required properties", with the exceptions listed in parenthesis. So
the Dove GPU, which is a combined 2D/3D core should have axi, core and
shader clocks specified.

Regards,
Lucas


  reply	other threads:[~2020-05-14  8:41 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <[PATCH 0/3] drm/etnaviv: Clock fixes>
2020-05-13 15:00 ` Lubomir Rintel
2020-05-13 15:00   ` [PATCH 1/3] drm/etnaviv: Fix error path on failure to enable bus clk Lubomir Rintel
2020-05-13 15:00   ` [PATCH 2/3] drm/etnaviv: Don't ignore errors on getting clocks Lubomir Rintel
2020-05-13 16:07     ` Fabio Estevam
2020-05-13 17:09     ` Fabio Estevam
2020-05-14  2:41       ` Fabio Estevam
2020-05-14  8:18         ` Lucas Stach
2020-05-14  8:27           ` Russell King - ARM Linux admin
2020-05-14  8:40             ` Lucas Stach [this message]
2020-05-14  8:53               ` Russell King - ARM Linux admin
2020-05-20 13:38                 ` Lubomir Rintel
2020-05-20 14:04                   ` Lucas Stach
2020-05-20 15:00                     ` Russell King - ARM Linux admin
2020-05-23 10:22                     ` Lubomir Rintel
2020-05-13 15:00   ` [PATCH 3/3] drm/etnaviv: Simplify clock enable/disable Lubomir Rintel

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