diff mbox series

[1/2] dt-bindings: nvmem: add STM32 TAMP NVRAM

Message ID 20260107194541.1843999-1-dario.binacchi@amarulasolutions.com
State New
Headers
Series [1/2] dt-bindings: nvmem: add STM32 TAMP NVRAM |

Commit Message

Dario Binacchi Jan. 7, 2026, 7:45 p.m. UTC 
Add devicetree bindings for TAMP backup registers. These 32-bit
registers are retained in all low-power modes and in VBAT mode. As a
result, they can also be used to store sensitive data because their
content is protected by a tamper detection circuit.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

 .../bindings/nvmem/st,stm32-tamp-nvram.yaml   | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml

Comments

'Abel Vesa' via Amarula Linux Jan. 8, 2026, 4:13 p.m. UTC | #1 
On Wed, 07 Jan 2026 20:45:32 +0100, Dario Binacchi wrote:
> Add devicetree bindings for TAMP backup registers. These 32-bit
> registers are retained in all low-power modes and in VBAT mode. As a
> result, they can also be used to store sensitive data because their
> content is protected by a tamper detection circuit.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
>  .../bindings/nvmem/st,stm32-tamp-nvram.yaml   | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
> 


My bot found new DTB warnings on the .dts files added or changed in this
series.

Some warnings may be from an existing SoC .dtsi. Or perhaps the warnings
are fixed by another series. Ultimately, it is up to the platform
maintainer whether these warnings are acceptable or not. No need to reply
unless the platform maintainer has comments.

If you already ran DT checks and didn't see these error(s), then
make sure dt-schema is up to date:

  pip3 install dtschema --upgrade


This patch series was applied (using b4) to base:
 Base: f0b9d8eb98dfee8d00419aa07543bdc2c1a44fb1 (use --merge-base to override)

If this is not the correct base, please add 'base-commit' tag
(or use b4 which does this automatically)

New warnings running 'make CHECK_DTBS=y for arch/arm64/boot/dts/st/' for 20260107194541.1843999-1-dario.binacchi@amarulasolutions.com:

arch/arm64/boot/dts/st/stm32mp257f-dk.dtb: tamp@46010000 (st,stm32-tamp): '#address-cells', '#size-cells', 'nvram@46010100', 'ranges' do not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/arm/stm32/st,stm32-syscon.yaml
arch/arm64/boot/dts/st/stm32mp257f-ev1.dtb: tamp@46010000 (st,stm32-tamp): '#address-cells', '#size-cells', 'nvram@46010100', 'ranges' do not match any of the regexes: '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/arm/stm32/st,stm32-syscon.yaml





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'Abel Vesa' via Amarula Linux Jan. 15, 2026, 2:54 p.m. UTC | #2 
On Wed, Jan 07, 2026 at 08:45:32PM +0100, Dario Binacchi wrote:
> Add devicetree bindings for TAMP backup registers. These 32-bit
> registers are retained in all low-power modes and in VBAT mode. As a
> result, they can also be used to store sensitive data because their
> content is protected by a tamper detection circuit.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
>  .../bindings/nvmem/st,stm32-tamp-nvram.yaml   | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml b/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
> new file mode 100644
> index 000000000000..e03469fbe436
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
> @@ -0,0 +1,55 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/nvmem/st,stm32-tamp-nvram.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STMicroelectronics STM32 TAMP's NVRAM
> +
> +description: |

Don't need '|' if no formatting.

> +  The TAMP peripheral integrates, amongst others, Non Volatile RAM

What others? Are you saying this binding is incomplete?

> +  (NVRAM) with 32/128 32-bit backup registers which can be used by
> +  software to store information or communicate with a boot loader.

Wrap lines at 80 char.

> +
> +maintainers:
> +  - Dario Binacchi <dario.binacchi@amarulasolutions.com>
> +
> +allOf:
> +  - $ref: nvmem.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - st,stm32mp15-tamp-nvram
> +      - st,stm32mp25-tamp-nvram
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    nvram: nvram@46010100 {
> +        compatible = "st,stm32mp25-tamp-nvram";
> +        reg = <0x46010100 0x200>;
> +
> +        nvmem-layout {
> +            compatible = "fixed-layout";
> +            #address-cells = <1>;
> +            #size-cells = <1>;
> +
> +            fwu_info: tamp-bkp@c0 {
> +                reg = <0xc0 0x4>;
> +            };
> +
> +            boot_mode: tamp-bkp@180 {
> +                reg = <0x180 0x4>;
> +            };
> +        };
> +    };
> +...
> -- 
> 2.43.0
> 
> base-commit: f0b9d8eb98dfee8d00419aa07543bdc2c1a44fb1
> branch: stm32-tamp-nvram

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diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml b/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
new file mode 100644
index 000000000000..e03469fbe436
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/st,stm32-tamp-nvram.yaml
@@ -0,0 +1,55 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/st,stm32-tamp-nvram.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 TAMP's NVRAM
+
+description: |
+  The TAMP peripheral integrates, amongst others, Non Volatile RAM
+  (NVRAM) with 32/128 32-bit backup registers which can be used by
+  software to store information or communicate with a boot loader.
+
+maintainers:
+  - Dario Binacchi <dario.binacchi@amarulasolutions.com>
+
+allOf:
+  - $ref: nvmem.yaml#
+
+properties:
+  compatible:
+    enum:
+      - st,stm32mp15-tamp-nvram
+      - st,stm32mp25-tamp-nvram
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    nvram: nvram@46010100 {
+        compatible = "st,stm32mp25-tamp-nvram";
+        reg = <0x46010100 0x200>;
+
+        nvmem-layout {
+            compatible = "fixed-layout";
+            #address-cells = <1>;
+            #size-cells = <1>;
+
+            fwu_info: tamp-bkp@c0 {
+                reg = <0xc0 0x4>;
+            };
+
+            boot_mode: tamp-bkp@180 {
+                reg = <0x180 0x4>;
+            };
+        };
+    };
+...