Re: [PATCH v2 3/4] ASoC: dt-bindings: fsl-sai: allow only one dma-names

[Conor Dooley <conor@xxxxxxxxxx>]

On Thu, Feb 29, 2024 at 02:38:24PM -0500, Frank Li wrote:
> On Thu, Feb 29, 2024 at 06:57:29PM +0000, Conor Dooley wrote:
> > On Thu, Feb 29, 2024 at 06:55:58PM +0000, Conor Dooley wrote:
> > > On Tue, Feb 27, 2024 at 03:54:11PM -0500, Frank Li wrote:
> > > > Some sai only connect one direction. So allow only "rx" or "tx" for
> > > > dma-names.
> > > 
> > > Which sai? Can you restrict this per compatible please, so that someone
> > > cannot add 2 dmas for ones where only the tx is supported.
> > > 
> > > |  dmas:
> > > |    minItems: 1
> > > |    items:
> > > |      - description: DMA controller phandle and request line for RX
> > > |      - description: DMA controller phandle and request line for TX
> > > 
> > > The binding already allows only one, but it documents that the first dma
> > > is always the RX dma, and that doesn't change with this patch..
> > 
> > I said "doesn't change" - but I don't think you can change this
> > trivially, as something could rely on the first dma being the rx one.
> > You'd have to check that there is nothing using these using indices
> > rather than names before making any changes here.
> 
> Linux driver and dts with tx only work well. Only issue is dtb_check will
> report error. I want to eliminate these DTB_CHECK warning.

Linux is not the only user of these bindings, citing linux as your
evidence here is only sufficient if no other users exist. Do they?

> And it also reasonable, only rx or tx for a special SAI.
> 
> Can we remove 'description'? dmas should already descripted at common place
> and 'RX' and 'TX' are listed at 'dma-names'

Removing the description has the same problem. The existing binding has
set a fixed order that you now want to make flexible.

Thanks,
Conor.

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