[PATCH 2/5] USB: Add Cypress c67x00 low level interface code

David Brownell david-b at pacbell.net
Sun Nov 25 06:39:23 EST 2007

On Friday 23 November 2007, Grant Likely wrote:
> +/* These functions could also be implemented with SPI of HSS.
> + * This is currently not supported */

Give that this "HPI" interface seems to use a parallel bus
with irq-safe synchronous accesses, and SPI is a serial bus
where synchronous accesses can't be done in IRQ context ...
that comment doesn't seem accurate.

Surely a more correct statement would be that while the chip
can also be accessed using SPI, that would require updating
the driver structure to stop assuming register accesses can
always be done from IRQ context?

If that's not the case, then those spinlocks are overkill,
and they should become mutexes.  :)

- Dave

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