[PATCH] spi: Add check for 8-bit transfer with 8 IO mode support

[PATCH] spi: Add check for 8-bit transfer with 8 IO mode support

[Cheng Ming Lin]

From: Cheng Ming Lin <chengminglin@mxic.com.tw>

The current SPI framework does not verify if the SPI device supports
8 IO mode when doing an 8-bit transfer. This patch adds a check to
ensure that if the transfer tx_nbits or rx_nbits is 8, the SPI mode must
support 8 IO. If not, an error is returned, preventing undefined behavior.

Fixes: d6a711a898672 ("spi: Fix OCTAL mode support")
Cc: stable@vger.kernel.org
Signed-off-by: Cheng Ming Lin <chengminglin@mxic.com.tw>
---
 drivers/spi/spi.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1bc0fdbb1bd7..0ffa3f9f2870 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -4138,10 +4138,13 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 				xfer->tx_nbits != SPI_NBITS_OCTAL)
 				return -EINVAL;
 			if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
-				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
+				!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL)))
 				return -EINVAL;
 			if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
-				!(spi->mode & SPI_TX_QUAD))
+				!(spi->mode & (SPI_TX_QUAD | SPI_TX_OCTAL)))
+				return -EINVAL;
+			if ((xfer->tx_nbits == SPI_NBITS_OCTAL) &&
+				!(spi->mode & SPI_TX_OCTAL))
 				return -EINVAL;
 		}
 		/* Check transfer rx_nbits */
@@ -4154,10 +4157,13 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 				xfer->rx_nbits != SPI_NBITS_OCTAL)
 				return -EINVAL;
 			if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
-				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
+				!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
 				return -EINVAL;
 			if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
-				!(spi->mode & SPI_RX_QUAD))
+				!(spi->mode & (SPI_RX_QUAD | SPI_RX_OCTAL)))
+				return -EINVAL;
+			if ((xfer->rx_nbits == SPI_NBITS_OCTAL) &&
+				!(spi->mode & SPI_RX_OCTAL))
 				return -EINVAL;
 		}
 
-- 
2.25.1

Re: [PATCH] spi: Add check for 8-bit transfer with 8 IO mode support

[Mark Brown]

On Mon, 14 Jul 2025 11:10:23 +0800, Cheng Ming Lin wrote:
> The current SPI framework does not verify if the SPI device supports
> 8 IO mode when doing an 8-bit transfer. This patch adds a check to
> ensure that if the transfer tx_nbits or rx_nbits is 8, the SPI mode must
> support 8 IO. If not, an error is returned, preventing undefined behavior.
> 
> 

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: Add check for 8-bit transfer with 8 IO mode support
      commit: 710505212e3272396394f8cf78e3ddfd05df3f22

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark