Re: [PATCH] atmel_spi: support zero length transfer

[Ned Forrester <nforrester-/d+BM93fTQY@public.gmane.org>]

Atsushi Nemoto wrote:

> If the driver could not handle zero length transfer, then the driver
> should reject it (just like unsupported transfer mode).  Then the
> behavior will be 'assert chip select and wait some time' or 'rejected
> by the driver'.

This would be OK.  It would not be hard to fix pxa2xx_spi, for example,
to reject zero-length transfers in DMA mode, as long as it is acceptable
to reject the message in mid-message.  If it were necessary to scan a
whole message for zero-length transfers and refuse to queue an offending
message, then that adds burden to all messages.

-- 
Ned Forrester                                       nforrester-/d+BM93fTQY@public.gmane.org
Oceanographic Systems Lab                                  508-289-2226
Applied Ocean Physics and Engineering Dept.
Woods Hole Oceanographic Institution          Woods Hole, MA 02543, USA
http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212
http://www.whoi.edu/hpb/Site.do?id=1532
http://www.whoi.edu/page.do?pid=10079


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