This is a note to let you know that I've just added the patch titled ARM: dts: stm32: Reduce DHCOR SPI NOR frequency to 50 MHz to the 5.14-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: arm-dts-stm32-reduce-dhcor-spi-nor-frequency-to-50-m.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 49c05105c40357926cba50b71bbc1cf583213a15 Author: Marek Vasut <marex@xxxxxxx> Date: Mon Aug 9 14:13:24 2021 +0200 ARM: dts: stm32: Reduce DHCOR SPI NOR frequency to 50 MHz [ Upstream commit 2012579b31293d0a8cf2024e9dab66810bf1a15e ] The SPI NOR is a bit further away from the SoC on DHCOR than on DHCOM, which causes additional signal delay. At 108 MHz, this delay triggers a sporadic issue where the first bit of RX data is not received by the QSPI controller. There are two options of addressing this problem, either by using the DLYB block to compensate the extra delay, or by reducing the QSPI bus clock frequency. The former requires calibration and that is overly complex, so opt for the second option. Fixes: 76045bc457104 ("ARM: dts: stm32: Add QSPI NOR on AV96") Signed-off-by: Marek Vasut <marex@xxxxxxx> Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> Cc: Patrice Chotard <patrice.chotard@xxxxxxxxxxx> Cc: Patrick Delaunay <patrick.delaunay@xxxxxxxxxxx> Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi index 2b0ac605549d7..44ecc47085871 100644 --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi @@ -202,7 +202,7 @@ compatible = "jedec,spi-nor"; reg = <0>; spi-rx-bus-width = <4>; - spi-max-frequency = <108000000>; + spi-max-frequency = <50000000>; #address-cells = <1>; #size-cells = <1>; };