This is a note to let you know that I've just added the patch titled
serial: sc16is7xx: add check for unsupported SPI modes during probe
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-sc16is7xx-add-check-for-unsupported-spi-modes.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c9782adceee73d616a03c3b8e3229d3f9bdbb3bb
Author: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
Date: Thu Dec 21 18:18:09 2023 -0500
serial: sc16is7xx: add check for unsupported SPI modes during probe
[ Upstream commit 6d710b769c1f5f0d55c9ad9bb49b7dce009ec103 ]
The original comment is confusing because it implies that variants other
than the SC16IS762 supports other SPI modes beside SPI_MODE_0.
Extract from datasheet:
The SC16IS762 differs from the SC16IS752 in that it supports SPI clock
speeds up to 15 Mbit/s instead of the 4 Mbit/s supported by the
SC16IS752... In all other aspects, the SC16IS762 is functionally and
electrically the same as the SC16IS752.
The same is also true of the SC16IS760 variant versus the SC16IS740 and
SC16IS750 variants.
For all variants, only SPI mode 0 is supported.
Change comment and abort probing if the specified SPI mode is not
SPI_MODE_0.
Fixes: 2c837a8a8f9f ("sc16is7xx: spi interface is added")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231221231823.2327894-3-hugo@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index ce0681ba7734..892e27cddb0f 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1413,7 +1413,10 @@ static int sc16is7xx_spi_probe(struct spi_device *spi)
/* Setup SPI bus */
spi->bits_per_word = 8;
- /* only supports mode 0 on SC16IS762 */
+ /* For all variants, only mode 0 is supported */
+ if ((spi->mode & SPI_MODE_X_MASK) != SPI_MODE_0)
+ return dev_err_probe(&spi->dev, -EINVAL, "Unsupported SPI mode\n");
+
spi->mode = spi->mode ? : SPI_MODE_0;
spi->max_speed_hz = spi->max_speed_hz ? : 4 * HZ_PER_MHZ;
ret = spi_setup(spi);
