spi/dw_spi: conditional transfer mode changes
commit052dc7c45d8f685fb3720a08331ba3e91e87937e
authorGeorge Shore <george@georgeshore.com>
Thu, 21 Jan 2010 11:40:52 +0000 (21 11:40 +0000)
committerGrant Likely <grant.likely@secretlab.ca>
Thu, 21 Jan 2010 14:25:32 +0000 (21 07:25 -0700)
treeb874258f108a2ac2d8dbec12a137562d4ea4b402
parentf4aec798ae5a837a1f062e295f9a5f1b00962589
spi/dw_spi: conditional transfer mode changes

This allows the switching between transfer modes between 'transmit only',
'receive only' and 'transmit and receive' modes. Due to the design of the SPI
block, changing transfer modes requires that the block be disabled; in doing
so the chipselect line is inherently deasserted and (usually) the attached
device discards its state. Consequentially, switching modes requires that a
platform-specific chipselect function has been defined so that the chipselect
is not dropped during the change.

Signed-off-by: George Shore <george@georgeshore.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
drivers/spi/dw_spi.c