Re: [PATCH v2 1/2] dt-bindings: spi: Update clocks property for ARM pl022

From: Kuldeep Singh <singh.kuldeep87k@gmail.com>
To: Rob Herring <robh@kernel.org>
Cc: Mark Brown <broonie@kernel.org>,
	linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org,
	devicetree@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Subject: Re: [PATCH v2 1/2] dt-bindings: spi: Update clocks property for ARM pl022
Date: Fri, 11 Mar 2022 08:25:02 +0530	[thread overview]
Message-ID: <20220311025502.GB54098@9a2d8922b8f1> (raw)
In-Reply-To: <Yip2MZdQNjMz/Cos@robh.at.kernel.org>

On Thu, Mar 10, 2022 at 04:05:37PM -0600, Rob Herring wrote:
> On Tue, Mar 08, 2022 at 12:51:24PM +0530, Kuldeep Singh wrote:
> > Add missing minItems property to clocks in ARM pl022 bindings.
> > 
> > This helps in resolving below warnings:
> > clocks: [[4]] is too short
> > clock-names: ['apb_pclk'] is too short
> 
> Again, the error is in the dts files, not the schema.

Rob, kindly note this series number is deprecated and I have sent v3
version some time back. Here's the link:

https://lore.kernel.org/linux-spi/20220309171847.5345-1-singh.kuldeep87k@gmail.com/T/#u

> 
> 
> There's 2 possible answers. First, both clock inputs use the same source 
> clock. That's an easy fix. List the clock twice. Second, one clock is 
> not described in DT or visible to s/w. It still has to be in the h/w and 
> could be described as a 'fixed-clock'. A DT should either be all in with 
> clocks or not use the clock binding IMO. Describing some clocks and not 
> others is not a good solution.
> 
> For example, let's look at bcm-cygnus as one of the single clock 
> examples. The first thing I notice is there is a apb_pclk already 
> defined. The pl330 uses it. The watchdog (also Primecell) lists the 
> source clock twice. So what should pl022 be? IDK, ask the Broadcom 
> folks. If they don't know, then list the source clock twice. That's 
> effectively no change from what we have now.

Yes, I took motivation from sp805 watchdog(primecell) while resolving DT
conflicts. I found LG and amd seattle platform with single clock in DT
for which I have sent patches. Link is below:

https://lore.kernel.org/linux-devicetree/CAL_Jsq+k+ridWTkdy4xwTC7VxUTU8tu+Q2BA9kbQVA222PWvZw@mail.gmail.com/

Moreover, I observed that clocks and clock-names are not required
properties for pl022. I am wondering reason behind the same when you
first made changes. Any specific reason not adding them which I am not
aware of or it just got missed?

- Kuldeep

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