On Fri, Oct 28, 2022 at 12:50:18AM +0200, Marek Vasut wrote: > Add trivial bindings for driver which permits exposing syscon backed > register to userspace. This is useful e.g. to expose U-Boot boot > counter on various platforms where the boot counter is stored in > random volatile register, like STM32MP15xx TAMP_BKPxR register. Generic bindings always start trivial until they get appended one property at a time... What happens when you have more than 1 field and/or more than 1 register? > Signed-off-by: Marek Vasut <marex@xxxxxxx> > --- > Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> > Cc: Rafał Miłecki <rafal@xxxxxxxxxx> > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> > Cc: devicetree@xxxxxxxxxxxxxxx > Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx > To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > --- > .../bindings/nvmem/nvmem-syscon.yaml | 39 +++++++++++++++++++ > 1 file changed, 39 insertions(+) > create mode 100644 Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml > > diff --git a/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml b/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml > new file mode 100644 > index 0000000000000..3035a0b2cd24a > --- /dev/null > +++ b/Documentation/devicetree/bindings/nvmem/nvmem-syscon.yaml > @@ -0,0 +1,39 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/nvmem/nvmem-syscon.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Generic syscon backed nvmem > + > +maintainers: > + - Marek Vasut <marex@xxxxxxx> > + > +allOf: > + - $ref: "nvmem.yaml#" > + > +properties: > + compatible: > + enum: > + - nvmem-syscon > + > + reg: > + maxItems: 1 > + > +required: > + - compatible > + - reg > + > +additionalProperties: false > + > +examples: > + - | > + tamp@5c00a000 { > + compatible = "st,stm32-tamp", "syscon", "simple-mfd"; This is very common, but personally I think "syscon" and "simple-mfd" should be mutually exclusive. "simple-mfd" is saying the children have no dependency on the parent, yet the child nodes need a regmap from the parent. Sounds like a dependency. > + reg = <0x5c00a000 0x400>; > + > + nvmem-syscon { > + compatible = "nvmem-syscon"; > + reg = <0x14c 0x4>; How does one identify this is the bootloader's boot count? How does the bootloader know it can write to this? > + }; > + }; > -- > 2.35.1 > >
