Hi everyone,
I’m working with the Verdin AM625 module on the Dahlia carrier board and trying to enable UART4 for a custom application. I’m using the default device tree “k3-am625-verdin-wifi-dahlia.dts”
for the Dahlia board, but can’t seem to get this UART interface properly exposed to Linux as a general purpose serial UART.
It is by default a Linux debug console, but I have not set it to be acting as a console anywhere in our image configuration. In the Toradex documentation, this port is reserved for the M4 MCU, so how can i enable it as a normal UART.
Below are the snippets of my current device tree configuration for UART4:
- Pinmux Configuration:
/* Verdin UART_4 - Reserved to Cortex-M4 */
pinctrl_mcu_uart0: mcu-uart0-default-pins {
pinctrl-single,pins = <
AM62X_MCU_IOPAD(0x0014, PIN_INPUT_PULLUP, 0) /* (B5) MCU_UART0_RXD */ /* SODIMM 151 */
AM62X_MCU_IOPAD(0x0018, PIN_OUTPUT, 0) /* (A5) MCU_UART0_TXD */ /* SODIMM 153 */
>;
};
- UART Node Configuration:
&mcu_uart0 {
status = "okay";
};
- Relevant Alias (if needed):
/ {
aliases {
can0 = &main_mcan0;
can1 = &mcu_mcan0;
ethernet0 = &cpsw_port1;
ethernet1 = &cpsw_port2;
i2c0 = &main_i2c0;
i2c1 = &main_i2c1;
i2c2 = &main_i2c2;
i2c3 = &mcu_i2c0;
i2c4 = &main_i2c3;
mmc0 = &sdhci0;
mmc1 = &sdhci1;
mmc2 = &sdhci2;
rtc0 = &rtc_i2c;
rtc1 = &wkup_rtc0;
serial0 = &main_uart1;
serial1 = &wkup_uart0;
serial2 = &main_uart0;
serial3 = &mcu_uart0;
serial4 = &main_uart5;
usb0 = &usb0;
usb1 = &usb1;
};
};
After applying these changes, I’ve recompiled and deployed the device tree, I can see UART4 as /dev/ttyS3 but when i connect to it i access the Linux console terminal.
What must i do to disable this UART as a debug console and enable it as a standard UART serial port. I believe this behavior has to do with the onboard M4 MCU, but I found no documentation on how to disable Linux/MCU from using UART4 as a debug serial. There as some instructions on how to do it for other "non TI based modules such as the Verdin iMX8, but nothing for the Verdin AM625.
Are there any additional changes I need to make to expose UART4 properly?
Do I need to modify the u-boot configuration or make any adjustments in the kernel?
I’d appreciate any guidance or suggestions from the community. If you need further details about my setup or configurations, feel free to ask.
Thanks in advance for your help!
