Using uart1 on mediatek mt8195 derived board

[Thomas Schaefer]

Hi Macpaul, Fabien,

I'm referring to patch series https://patchwork.ozlabs.org/project/uboot/patch/20230804110448.24589-1-macpaul.lin@mediatek.com/ where support for the mediatek mt8195 SOC is introduced into u-boot. We are developing a board based on the mt8195 as well but we want to use UART1 instead of UART0 for debug output messages.

Our board is booting and we see boot messages on a debug pin header connected to UART0 when using the settings from the demo board, but when trying to switch to UART1, no more messages appear on the console. What we have tried is the following:

- Adaptation of the dts and dtsi files with uart1 settings taken from linux device tree:

diff --git a/arch/arm/dts/mt8195.dtsi b/arch/arm/dts/mt8195.dtsi
index a7e4db5aa7..53eb437fad 100644
--- a/arch/arm/dts/mt8195.dtsi
+++ b/arch/arm/dts/mt8195.dtsi
@@ -245,6 +245,17 @@
                        status = "disabled";
                };

+               uart1: serial at 11001200 {
+                       compatible = "mediatek,mt8195-uart",
+                                    "mediatek,hsuart";
+                       reg = <0 0x11001200 0 0x1000>;
+                       interrupts = <GIC_SPI 91 IRQ_TYPE_LEVEL_LOW>;
+                       clock-frequency = <26000000>;
+                       clocks = <&clk26m>, <&clk26m>;
+                       clock-names = "baud", "bus";
+                       status = "disabled";
+               };
+
                pericfg_ao: syscon at 11003000 {
                        compatible = "mediatek,mt8195-pericfg_ao", "syscon";
                        reg = <0 0x11003000 0 0x1000>;

diff --git a/arch/arm/dts/mt8195-kontron-sbc-i1200.dts b/arch/arm/dts/mt8195-kontron-sbc-i1200.dts
index c6ea7e8f3d..4700a6d303 100644
--- a/arch/arm/dts/mt8195-kontron-sbc-i1200.dts
+++ b/arch/arm/dts/mt8195-kontron-sbc-i1200.dts
@@ -58,7 +58,7 @@
        };

        chosen {
-               stdout-path = &uart0;
+               stdout-path = &uart1;
        };

        reg_1p8v: regulator-1p8v {
@@ -121,7 +121,7 @@
        status = "okay";
 };

-&uart0 {
+&uart1 {
        status = "okay";
 };

We also tried to change the DEBUG_UART settings in the defconfig to match with UART1, but without success.

Are there any special means to make UART1 interface run?

Best regards,
Thomas

Thomas Schäfer
SW Design Engineer

T:
+49 681 95916 203


thomas.schaefer at kontron.com
www.kontron.com



            
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