Messages in this thread | | | Subject | Re: [PATCH 4/4] dt-bindings: spi: Convert cadence-quadspi.txt to cadence-quadspi.yaml | From | Vignesh Raghavendra <> | Date | Thu, 1 Apr 2021 13:57:49 +0530 |
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On 3/29/21 11:52 PM, Pratyush Yadav wrote: >>> + cdns,fifo-depth: >>> + description: >>> + Size of the data FIFO in words. >>> + $ref: "/schemas/types.yaml#/definitions/uint32" >>> + enum: [ 128, 256 ] >>> + default: 128 >>> + >>> + cdns,fifo-width: >>> + $ref: /schemas/types.yaml#/definitions/uint32 >>> + description: >>> + Bus width of the data FIFO in bytes. >>> + default: 4 >> I assume there's some constraints on this? > IIUC this is a matter of how the peripheral is implemented and there are > no clear constraints. Different implementations can use different bus > widths for the SRAM bus but I don't see any mention of minimum or > maximum values. FWIW, all users in the kernel use a 4 byte bus. >
IMO a safe constraint would be to set a range of 1 to 4 (8/16/24/32 bit wide) given this represents SRAM bus width. Binding can always be updated if there exists an implementation with higher SRAM bus width/fifo-width (although that's highly unlikely given there are no such examples today).
But leaving it open ended with range of 0 to UINT_MAX sounds incorrect to me.
>> With that, >> >> Reviewed-by: Rob Herring <robh@kernel.org> > Thanks. >
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