spi: introduce macros to set bits_per_word_mask
Introduce two macros to make setting up spi_master.bits_per_word_mask
easier, and avoid mistakes like writing BIT(n) instead of BIT(n - 1).
SPI_BPW_MASK is for a single supported value of bits_per_word_mask.
SPI_BPW_RANGE_MASK represents a contiguous set of bit lengths.
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 6ff26c8..1737256 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -308,6 +308,8 @@
/* bitmask of supported bits_per_word for transfers */
u32 bits_per_word_mask;
+#define SPI_BPW_MASK(bits) BIT((bits) - 1)
+#define SPI_BPW_RANGE_MASK(min, max) ((BIT(max) - 1) - (BIT(min) - 1))
/* other constraints relevant to this driver */
u16 flags;