I have connection to ttyAML6 after running the ldto command below and I can control the device but no confirmation is present when sending commands and I cannot set the baud rate to match the 3d printer controller.
sudo ldto merge uarta uarta-clk81 uart-a
$ dmesg | grep tty [ 0.001163] printk: console [tty0] enabled [ 1.234161] c11084c0.serial: ttyAML6 at MMIO 0xc11084c0 (irq = 22, base_baud = 10416666) is a meson_uart [ 1.235375] c81004c0.serial: ttyAML0 at MMIO 0xc81004c0 (irq = 23, base_baud = 1500000) is a meson_uart [ 2.568371] printk: console [ttyAML0] enabled [ 5.048295] systemd: Created slice system-getty.slice. [ 5.084058] systemd: Created slice system-serial\x2dgetty.slice.
but speed reports as 0 and have not tested any printing yet.
$ stty < /dev/ttyAML6 speed 0 baud; line = 0; min = 0; time = 0; -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke