[PATCH] arm64: dts: ti: k3-am64-mcu: explicitly assign UART base clock rates

From: Matthias Schiffer
Date: Mon Apr 11 2022 - 08:11:33 EST


We found that (at least some versions of) the sci-fw do not assign the
expected base clock rate of 48 MHz for the UARTs in the MCU domain,
leading to incorrect baud rates when used from Linux. Use
assigned-clock-rates to fix this issue.

Fixes: 8abae9389bdb ("arm64: dts: ti: Add support for AM642 SoC")
Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
---

I'm not sure if this is the best fix. Should the clock-frequency
property simply be removed, so the frequency is queried from the clock
driver instead?

arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
index 2bb5c9ff172c..69b0f127eea5 100644
--- a/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am64-mcu.dtsi
@@ -15,6 +15,8 @@ mcu_uart0: serial@4a00000 {
power-domains = <&k3_pds 149 TI_SCI_PD_EXCLUSIVE>;
clocks = <&k3_clks 149 0>;
clock-names = "fclk";
+ assigned-clocks = <&k3_clks 149 0>;
+ assigned-clock-rates = <48000000>;
};

mcu_uart1: serial@4a10000 {
@@ -26,6 +28,8 @@ mcu_uart1: serial@4a10000 {
power-domains = <&k3_pds 160 TI_SCI_PD_EXCLUSIVE>;
clocks = <&k3_clks 160 0>;
clock-names = "fclk";
+ assigned-clocks = <&k3_clks 160 0>;
+ assigned-clock-rates = <48000000>;
};

mcu_i2c0: i2c@4900000 {
--
2.25.1