[PATCH v2 1/1] arm64: dts: ti: k3-am62-wakeup: Configure ti-sysc for wkup_uart0

[Tony Lindgren]

* Kevin Hilman <khilman at kernel.org> [231205 18:14]:
> I'm a little confused why these power-domain and clocks stay here and
> are not moved under the wkup_uart0 node... 

The resources are also needed by the interconnect target module. It's the
wrapper IP for the child device(s). In this case there's one chip 8250 IP
instance. In some other devices there can be multiple child IP devices
wired to one target module.

> > -		clock-names = "fclk";
> > -		status = "disabled";
> > +		clock-names = "fck";
> > +		#address-cells = <1>;
> > +		#size-cells = <1>;
> > +		ranges = <0 0 0x2b300000 0x100000>;
> > +
> > +		wkup_uart0: serial at 2b300000 {
> > +			compatible = "ti,am64-uart", "ti,am654-uart";
> > +			reg = <0 0x100>;
> > +			interrupts = <GIC_SPI 186 IRQ_TYPE_LEVEL_HIGH>;
> > +			status = "disabled";
> 
> ...here.
> 
> The SCI device ID 114 is specifically for wkup_uart0[1], so it seems to
> me those should be in the wkup_uart0 node.

Those resources are also needed for the parent target module for revision
detection, quirks, reset, idle register configuration, and to probe the
child devices.

Here the 8250 IP can be set to status = "reserved" when used by the
firmware, and 8250 not touched by Linux. However, the parent interconnect
target module still needs to be configured for idle registers and wake-up
path register bit so the wake-up from deeper suspend states works.

Regards,

Tony