[Linux-stm32] [PATCH 2/2] arm64: dts: st: add TAMP-NVRAM support for STM32MP25

[Dario Binacchi]

Hello Patrice,

On Fri, Jan 9, 2026 at 11:40 AM Patrice CHOTARD
<patrice.chotard at foss.st.com> wrote:
>
>
>
> On 1/7/26 20:45, Dario Binacchi wrote:
> > Add the TAMP node along with its NVRAM child node and define the
> > fixed-layout for fwu_info and boot_mode registers.
> >
> > The TAMP (Tamper and backup registers) block is a system controller that
> > provides access to backup registers as NVMEM storage that persists across
> > reboots.
> >
> > Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
> >
> > ---
> >
> >  arch/arm64/boot/dts/st/stm32mp251.dtsi | 26 ++++++++++++++++++++++++++
> >  1 file changed, 26 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/st/stm32mp251.dtsi b/arch/arm64/boot/dts/st/stm32mp251.dtsi
> > index a8e6e0f77b83..c7839e732f31 100644
> > --- a/arch/arm64/boot/dts/st/stm32mp251.dtsi
> > +++ b/arch/arm64/boot/dts/st/stm32mp251.dtsi
> > @@ -2084,6 +2084,32 @@ rtc: rtc at 46000000 {
> >                       status = "disabled";
> >               };
> >
> > +             tamp: tamp at 46010000 {
> > +                     compatible = "st,stm32-tamp", "syscon", "simple-mfd";
> > +                     #address-cells = <1>;
> > +                     #size-cells = <1>;
> > +                     reg = <0x46010000 0x400>;
> > +                     ranges;
> > +
> > +                     nvram: nvram at 46010100 {
> > +                             compatible = "st,stm32mp25-tamp-nvram";
> > +                             reg = <0x46010100 0x200>;
> > +                             nvmem-layout {
> > +                                     compatible = "fixed-layout";
> > +                                     #address-cells = <1>;
> > +                                     #size-cells = <1>;
> > +
> > +                                     fwu_info: tamp-bkp at c0 {
> > +                                             reg = <0xc0 0x4>;
> > +                                     };
> > +
> > +                                     boot_mode: tamp-bkp at 180 {
> > +                                             reg = <0x180 0x4>;
> > +                                     };
> > +                             };
> > +                     };
> > +             };
> > +
> >               pinctrl_z: pinctrl at 46200000 {
> >                       #address-cells = <1>;
> >                       #size-cells = <1>;
> Hi Dario
>
> At STMicroelectronics we intend to upstream tamp-vram driver for STM32MP series.
> If you don't see any objection, we prefer to manage it in our side.

Ok, no problems.

Thanks and regards,
Dario
>
> Thanks
> Patrice



-- 

Dario Binacchi

Senior Embedded Linux Developer

dario.binacchi at amarulasolutions.com

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