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Subject: Re: [PATCH 2/3] drm/etnaviv: Don't ignore errors on getting clocks
From:   Lucas Stach <l.stach@pengutronix.de>
To:     Fabio Estevam <festevam@gmail.com>, Lubomir Rintel <lkundrak@v3.sk>
Cc:     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>,
        Russell King <linux+etnaviv@armlinux.org.uk>
Date:   Thu, 14 May 2020 10:18:02 +0200
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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...

Regards,
Lucas