Re: [PATCH v2 2/4] dt-bindings: usb: mtk-xhci: Make all clocks required

From: "Nícolas F. R. A. Prado" <nfraprado@collabora.com>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	kernel@collabora.com,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-usb@vger.kernel.org
Subject: Re: [PATCH v2 2/4] dt-bindings: usb: mtk-xhci: Make all clocks required
Date: Wed, 29 Jun 2022 14:55:46 -0400	[thread overview]
Message-ID: <20220629185546.z6rn7xp3ejpmaupi@notapiano> (raw)
In-Reply-To: <93c6b7201533325cf7758637dd194a372f3c00c6.camel@mediatek.com>

On Tue, Jun 28, 2022 at 08:57:45AM +0800, Chunfeng Yun wrote:
> Hi Nícolas,
> 
> On Thu, 2022-06-23 at 15:37 -0400, Nícolas F. R. A. Prado wrote:
> > All of the clocks listed in the binding are always wired to the XHCI
> > controller hardware blocks on all SoCs. The reason some clocks were
> > made
> > optional in the binding was to account for the fact that depending on
> > the SoC, some of the clocks might be fixed (ie not controlled by
> > software).
> > 
> > Given that the devicetree should represent the hardware, make all
> > clocks
> > required in the binding. Subsequent patches will make the DTS changes
> > to
> > specify fixed-clocks for the clocks that aren't controllable.
> > 
> > Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
> > 
> > ---
> > 
> > Changes in v2:
> > - Undid clock list changes that allowed middle clocks to be missing
> > from
> >   v1 and made all clocks required instead
> > - Rewrote commit message and title
> > 
> >  Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml | 4 +
> > ---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-
> > xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-
> > xhci.yaml
> > index 63cbc2b62d18..1444d18ef9bc 100644
> > --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> > +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> > @@ -67,7 +67,6 @@ properties:
> >      maxItems: 1
> >  
> >    clocks:
> > -    minItems: 1
> >      items:
> >        - description: Controller clock used by normal mode
> >        - description: Reference clock used by low power mode etc
> > @@ -76,9 +75,8 @@ properties:
> >        - description: controller clock
> >  
> >    clock-names:
> > -    minItems: 1
> >      items:
> > -      - const: sys_ck  # required, the following ones are optional
> > +      - const: sys_ck
> >        - const: ref_ck
> >        - const: mcu_ck
> >        - const: dma_ck
> 
> This patch causes more check warning, I prefer to leave dt-bindings
> unchanged, but just fix mt8195's dts warning instead, thanks a lot

Hi Chunfeng,

the warnings reported by Rob's bot only happen if patches 3 and 4 aren't applied
to adapt the devicetrees. They are ABI breaking changes, but I understood this
as the desired solution from the discussion we had with Krzysztof on v1 [1].

I was expecting some feedback from Krzysztof or Matthias if this was an issue,
but it looks like Greg already merged the patch. I'll wait a bit for some
feedback and if this really was a misunderstanding I can send a revert patch.

Thanks,
Nícolas

[1] https://lore.kernel.org/all/20220622132219.36rvznhip2egujec@notapiano/

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