Re: [PATCH v1 0/3] serial: Support driver-selected TTY wakeup defaults

[Stefano Radaelli]

On Fri, Nov 06, 2026 at 03:00:40PM +0100, Johan Hovold wrote:
> On Tue, Nov 03, 2026 at 04:51:24PM +0100, Stefano Radaelli wrote:
> > The initial goal was to enable TTY wakeup by default on NXP LPUART ports
> > marked with wakeup-source, without requiring a userspace write. Instead
> > of keeping this entirely within fsl_lpuart, this series introduces a
> > common serial core mechanism that other UART drivers can also adopt.
> > 
> > The new tty_wakeup_default field in struct uart_port lets a driver request
> > wakeup to be enabled when its TTY device is registered. Each driver
> > decides whether to use it. This series adds wakeup-source to the LPUART
> > binding and makes fsl_lpuart the first user, setting the field from that
> > property. Other drivers retain their existing behavior, userspace can
> > still change power/wakeup, and serdev wakeup policy is unchanged.
> 
> This is a policy decision that should be left for userspace, not
> individual drivers. As documented in
> Documentation/driver-api/pm/devices.rst:
> 
> 	The initial value in the :file:`power/wakeup` file is "disabled"
> 	for the majority of devices; the major exceptions are power
> 	buttons, keyboards, and Ethernet adapters whose WoL
> 	(wake-on-LAN) feature has been set up with ethtool.
> 
> So no, this doesn't look like something we want. You should continue
> enabling wakeup from userspace on systems that need it instead.
> 
> Note that the "wakeup-source" devicetree attribute also describes
> capability, not policy:
> 
> 	Documentation/devicetree/bindings/power/wakeup-source.txt
> 
Hi Johan,

Understood, thanks for clarifying.
I incorrectly treated wakeup-source as a request to enable wakeup by default,
rather than as a capability description.
I will drop this series and keep wakeup enablement in userspace.

Thank you,
Best Regards,
Stefano