spi: add ability to validate xfer->bits_per_word in SPI core
Allow SPI masters to define the set of bits_per_word values they support.
If they do this, then the SPI core will reject transfers that attempt to
use an unsupported bits_per_word value. This eliminates the need for each
SPI driver to implement this checking in most cases.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index f996c600..0cabf15 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1377,6 +1377,14 @@
xfer->bits_per_word = spi->bits_per_word;
if (!xfer->speed_hz)
xfer->speed_hz = spi->max_speed_hz;
+ if (master->bits_per_word_mask) {
+ /* Only 32 bits fit in the mask */
+ if (xfer->bits_per_word > 32)
+ return -EINVAL;
+ if (!(master->bits_per_word_mask &
+ BIT(xfer->bits_per_word - 1)))
+ return -EINVAL;
+ }
}
message->spi = spi;