diff mbox series

[5.10,435/575] ARM: dts: stm32: Reduce DHCOR SPI NOR frequency to 50 MHz

Message ID 20211115165358.816966209@linuxfoundation.org (mailing list archive)
State New, archived
Headers show
Series None | expand

Commit Message

Greg KH Nov. 15, 2021, 5:02 p.m. UTC 
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 mbox series

Patch

diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi
index a9eb82b2f1704..5af32140e128b 100644
--- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi
+++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi
@@ -198,7 +198,7 @@ 
 		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>;
 	};