[PATCH] spi: add bits_per_word_mask check in spi_setup

[Scott Jiang <scott.jiang.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

The spi_setup should fail if underlying controller or its driver
does not support requested bits_per_word. So if the master driver
set mask and let core do bits_per_word check then we should also
test this mask in spi_setup.

Signed-off-by: Scott Jiang <scott.jiang.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/spi.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 45cb6a9..dc8fde0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1326,6 +1326,15 @@ int spi_setup(struct spi_device *spi)
 	if (!spi->bits_per_word)
 		spi->bits_per_word = 8;
 
+	if (spi->master->bits_per_word_mask) {
+		/* Only 32 bits fit in the mask */
+		if (spi->bits_per_word > 32)
+			return -EINVAL;
+		if (!(spi->master->bits_per_word_mask &
+				BIT(spi->bits_per_word - 1)))
+			return -EINVAL;
+	}
+
 	if (spi->master->setup)
 		status = spi->master->setup(spi);
 
-- 
1.7.0.4