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

[Rob Herring <robh@kernel.org>]

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.


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.

The other issue with allowing a single clock is then any new user can 
just repeat this mistake.

Rob