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 5.15-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-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1009c50874745b42332d27be040c4279b1e2c71b
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>;
};
