[Question] m25p80 driver versus spi clock rate

Steven A. Falco sfalco at harris.com
Wed Jun 24 12:14:58 EDT 2009

David Brownell wrote:
> On Wednesday 24 June 2009, Steven A. Falco wrote:
>> Your changes to bitbang_work look good.
> You tested?

Yes - I built a kernel with your patch, combined with the changes I
just posted to linuxppc-dev at ozlabs.org as:

"[PATCH v1] Make spi_ppc4xx.c tolerate 0 bits-per-word and 0 speed_hz"

I was successful in operating both the m25p16 at 16 MHz and the AVR
at 240 KHz, as verified by oscilloscope.  So my "ack" includes testing.

>> I'm not clear on why you first set do_setup = -1 but later 
>> use do_setup = 1.  Perhaps they should both be "1".  Other than that,
>> Acked-by: Steven A. Falco <sfalco at harris.com>
> The "-1" is for the init path, "1" for per-transfer overrides;
> this way it avoids some extra calls to set up the bits/speed.

Got it.  No further comments.  My "ack" stands.

I'll start looking at a revised version of the spi_ppc4xx.c driver,
integrating your comments.


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