Messages in this thread | | | Date | Fri, 3 Nov 2023 09:29:12 -0400 | From | Ben Wolsieffer <> | Subject | Re: [PATCH v2 3/5] dt-bindings: spi: add stm32f7-spi compatible |
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Hi Conor,
On Fri, Nov 03, 2023 at 12:50:53PM +0000, Conor Dooley wrote: > On Thu, Nov 02, 2023 at 03:37:20PM -0400, Ben Wolsieffer wrote: > A wider range of supported word sizes and some additional buffers, > implies that the F4 could be used as a fallback compatible. Does the > register map change incompatibly in the process of widening the FIFOs or > something like that?
Yes, the F4 has a single bit to select 8 or 16 bit word size, while the F7 uses four bits to select an arbitrary word size from 4 to 16 bits. This series supports the packing mode, to allow sending two <=8 bit words with a single write to the FIFO, but even if we didn't want to support this feature, the F7 would require setting the FRXTH bit (not present in the F4) when using <=8 bit word sizes.
> > Cheers, > Conor.
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