Messages in this thread | | | Date | Fri, 22 Feb 2008 09:28:11 -0500 | From | Ned Forrester <> | Subject | Re: [spi-devel-general] [PATCH] atmel_spi: support zero length transfer |
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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@whoi.edu 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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