From: Marek Vasut marex@denx.de
[ 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@denx.de Cc: Alexandre Torgue alexandre.torgue@foss.st.com Cc: Patrice Chotard patrice.chotard@foss.st.com Cc: Patrick Delaunay patrick.delaunay@foss.st.com Cc: linux-stm32@st-md-mailman.stormreply.com To: linux-arm-kernel@lists.infradead.org Signed-off-by: Alexandre Torgue alexandre.torgue@foss.st.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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>; };