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

[Kuldeep Singh <singh.kuldeep87k@gmail.com>]

On Fri, Mar 11, 2022 at 08:25:02AM +0530, Kuldeep Singh wrote:
> 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.

I just noticed not all platforms possessing single clock are raising
'dtbs_check' warning. For example, bcm-cygnus and lpc32xx passes check
even though their DT clock entry has just "apb_pclk".

Any reason why they pass successfully through checks?

> 
> 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