Re: [PATCH v4 7/8] ARM: dts: Declare UART1 on zx297520v3 boards

Arnd Bergmann
2026-04-17T09:00:11Z

On Thu, Apr 16, 2026, at 22:19, Stefan Dösinger wrote:
>
> The reason why I add the serial1=uart1 alias is to keep console=ttyAMA1
> stable regardless of the other enabled UARTs. UART0, as the name
> implies, has a lower MMIO address, but uart1 is the one that usually has
> the boot output and console.

I'm not sure I'm following here. You generally want to either make
sure the alias matches whatever number is printed on the product
if there are multiple numbered ports, or you just use 'serial0'
as the only alias if there is only one port.

> + aliases {
> + serial1 = &uart1;
> + };

Either way, the alias should go into the board specific file, not
the general SoC file, as a board might be using a different
set of UARTs.

> +
> + /* The UART clock defaults to 26 mhz. It will be replaced when the zx29 clock
> + * framework is added.
> + */
> + uartclk: uartclk: clock-26000000 {
> + #clock-cells = <0>;
> + compatible = "fixed-clock";
> + clock-frequency = <26000000>;
> + };
> +
> + uart1: serial@1408000 {
> + compatible = "arm,pl011", "arm,primecell";
> + arm,primecell-periphid = <0x001feffe>;
> + reg = <0x01408000 0x1000>;
> + interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;
> + clocks = <&uartclk>;
> + clock-names = "apb_pclk";
> + };

Since you know the addresses of the other uart instances, I would
suggest you add all of them at the same time.

Arnd