Re: [PATCH 3/3] arm64: boot: dts: ti: k3-am62l3-evm: enable WKUP UART wakeup from LPM

Nishanth Menon
2026-01-06T11:57:19Z

On 16:10-20260105, Kendall Willis wrote:
> On 1/5/26 07:55, Nishanth Menon wrote:
> > On 20:51-20251230, Kendall Willis wrote:
> > > Change the status of the wkup_uart0_interconnect node to enabled. The
> > > target-module node sets the UART SYSC and SYSS registers to allow wakeup
> > > from WKUP UART in DeepSleep low power mode.
> > >
> > > Signed-off-by: Kendall Willis <k-willis@ti.com>
> > > ---
> > > arch/arm64/boot/dts/ti/k3-am62l3-evm.dts | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/arch/arm64/boot/dts/ti/k3-am62l3-evm.dts b/arch/arm64/boot/dts/ti/k3-am62l3-evm.dts
> > > index cae04cce337366b50928d39b0c888550b14e43d3..02b1a1c76b2ee05d49cd69d199a6aacdb1973fa0 100644
> > > --- a/arch/arm64/boot/dts/ti/k3-am62l3-evm.dts
> > > +++ b/arch/arm64/boot/dts/ti/k3-am62l3-evm.dts
> > > @@ -359,3 +359,7 @@ &usb1 {
> > > pinctrl-names = "default";
> > > pinctrl-0 = <&usb1_default_pins>;
> > > };
> > > +
> > > +&wkup_uart0_interconnect {
> > > + status = "okay";
> > > +};
> >
> > don't we need to set status okay and provide pinmux for wkup_uart?
> >
>
> No, only the interconnect target node needs to be enabled because it manages
> the SYSC register. The SYSC register configures the WKUP_UART to be able to
> wakeup the SoC from system suspend. This allows the WKUP_UART to be wakeup
> capable even if it is reserved by firmware.
>

If wkup_uart is controlled by firmware, it should be managed by
firmware. $subject claims that wkup_uart is being enabled, but it is
not.

--
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D