Re: [PATCH v2] arm64: dts: rockchip: add attiny_rst_gate to Ringneck

[Quentin Schulz]

Hi Heiko,

On 9/27/24 11:39 AM, Heiko Stuebner wrote:
> Am Donnerstag, 26. September 2024, 15:24:03 CEST schrieb Quentin Schulz:
> > Hi Jakob,
> >
> > On 9/26/24 3:20 PM, Jakob Unterwurzacher wrote:
> > > Ringneck v1.4 can contain (placement option) an on-board ATtiny
> > > microcontroller instead of an STM32. In normal operation, this
> > > is transparent to the software, as both microcontrollers emulate
> > > the same ICs (amc6821 and isl1208).
> > >
> > > For flashing the ATtiny, the SWITCH_REG1 regulator of the board's PMIC is
> > > used to enable the ATtiny UPDI debug interface. If the STM32 is placed, or if
> > > we are running on an older Ringneck revision, SWITCH_REG1 is not connected
> > > and has no effect.
> > >
> > > Add attiny-updi-gate-regulator so userspace can control it via sysfs
> > > (needs CONFIG_REGULATOR_USERSPACE_CONSUMER):
> > >
> > >     echo enabled > /sys/devices/platform/attiny-updi-gate-regulator/state
> > >
> > > Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzacher@xxxxxxxxx>
> > > Tested-by: Quentin Schulz <quentin.schulz@xxxxxxxxx>
> >
> > Reviewed-by: Quentin Schulz <quentin.schulz@xxxxxxxxx>
> >
> > This is a candidate for backporting to stable branches as well I assume,
> > @Heiko?
>
> That is more on the darker side of gray here.
>
> Looking at the stable-kernel-rules [0] the criteria is
>    "It must either fix a real bug that bothers people or just add a device ID"
>
> This change instead is adding a new feature to allow said flashing from a
> running system.

This does mean that the new version of the device won't work as well 
with an older kernel though.

I thought the rules for DT backporting were a bit more permissive than 
for drivers. Maybe because most of the DT patches I posted were actual 
fixes :)

Up to you!

Cheers,
Quentin