This is a note to let you know that I've just added the patch titled serial: sc16is7xx: set safe default SPI clock frequency 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-set-safe-default-spi-clock-frequency.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. >From 3ef79cd1412236d884ab0c46b4d1921380807b48 Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Date: Thu, 21 Dec 2023 18:18:10 -0500 Subject: serial: sc16is7xx: set safe default SPI clock frequency From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> commit 3ef79cd1412236d884ab0c46b4d1921380807b48 upstream. 15 MHz is supported only by 76x variants. If the SPI clock frequency is not specified, use a safe default clock value of 4 MHz that is supported by all variants. Also use HZ_PER_MHZ macro to improve readability. Fixes: 2c837a8a8f9f ("sc16is7xx: spi interface is added") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231221231823.2327894-4-hugo@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/sc16is7xx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -24,6 +24,7 @@ #include <linux/tty_flip.h> #include <linux/spi/spi.h> #include <linux/uaccess.h> +#include <linux/units.h> #include <uapi/linux/sched/types.h> #define SC16IS7XX_NAME "sc16is7xx" @@ -1417,7 +1418,7 @@ static int sc16is7xx_spi_probe(struct sp 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 ? : 15000000; + spi->max_speed_hz = spi->max_speed_hz ? : 4 * HZ_PER_MHZ; ret = spi_setup(spi); if (ret) return ret; Patches currently in stable-queue which might be from hvilleneuve@xxxxxxxxxxxx are queue-5.4/serial-sc16is7xx-add-check-for-unsupported-spi-modes-during-probe.patch queue-5.4/serial-sc16is7xx-set-safe-default-spi-clock-frequency.patch