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

[Heiko Stuebner <heiko@sntech.de>]

Hey Quentin,

Am Freitag, 27. September 2024, 11:50:46 CEST schrieb Quentin Schulz:
> 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@cherry.de>
> >>> Tested-by: Quentin Schulz <quentin.schulz@cherry.de>
> >>
> >> Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
> >>
> >> 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.

"new version of the device" being the key here ;-) .

You also would not expect a new board dts or a new board variant to be
added to stable-kernels.


Heiko



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