spi: spi-fsl-spi: automatically adapt bits-per-word in cpu mode
authorRasmus Villemoes <rasmus.villemoes@prevas.dk>
Wed, 27 Mar 2019 14:30:52 +0000 (14:30 +0000)
committerMark Brown <broonie@kernel.org>
Tue, 2 Apr 2019 06:01:15 +0000 (13:01 +0700)
commitaf0e6242909c3c4297392ca3e94eff1b4db71a97
tree4ae786fa15f6de09bdef58c4566c737da62527ea
parenta798a7086c38d91d304132c194cff9f02197f5cd
spi: spi-fsl-spi: automatically adapt bits-per-word in cpu mode

Taking one interrupt for every byte is rather slow. Since the
controller is perfectly capable of transmitting 32 bits at a time,
change t->bits_per-word to 32 when the length is divisible by 4 and
large enough that the reduced number of interrupts easily compensates
for the one or two extra fsl_spi_setup_transfer() calls this causes.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-fsl-spi.c