On 05/06/2023 15:34, Mike Looijmans wrote: > Add bindings for a fixed-rate clock that retrieves its rate from an > NVMEM provider. This allows to store clock settings in EEPROM or EFUSE > or similar device. > > Component shortages lead to boards being shipped with different clock > crystals, based on what was available at the time. The clock frequency > was written to EEPROM at production time. Systems can adapt to a wide > range of input frequencies using the clock framework, but this required > us to patch the devicetree at runtime or use some custom driver. This > provides a more generic solution. > > Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx> > > --- > > Changes in v3: > Modify fixed-clock instead of introducing nvmem-clock > > Changes in v2: > Changed "fixed-clock" into "nvmem-clock" in dts example > Add minItems:1 to nvmem-cell-names > > .../bindings/clock/fixed-clock.yaml | 25 ++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/clock/fixed-clock.yaml b/Documentation/devicetree/bindings/clock/fixed-clock.yaml > index b0a4fb8256e2..23e4df96d3b0 100644 > --- a/Documentation/devicetree/bindings/clock/fixed-clock.yaml > +++ b/Documentation/devicetree/bindings/clock/fixed-clock.yaml > @@ -12,7 +12,9 @@ maintainers: > > properties: > compatible: > - const: fixed-clock > + enum: > + - fixed-clock > + - fixed-clock-nvmem Do you even need new compatible? Isn't this the same clock from the hardware point of view? > > "#clock-cells": > const: 0 > @@ -33,6 +35,27 @@ required: > > additionalProperties: false > Put it under allOf. Entire block should be before additionalProperties (just like in example-schema). > +if: > + properties: > + compatible: > + contains: > + const: fixed-clock-nvmem > + > +then: > + properties: > + nvmem-cells: > + maxItems: 2 Anyway, I don't think you tested it. Provide a DTS user of this. I don't think it works and such user would point to mistakes. Properties should be defined in top-level properties:, not in allOf:if:then. In allOf:if:then you only narrow them. > + description: > + Reads clock-frequency and/or clock-accuracy from an NVMEM provider in > + binary native integer format. The size of the NVMEM cell can be 1, 2, 4 > + or 8 bytes. If the contents of the nvmem are all zeroes or all 0xff, the > + value reverts to the one given in the property. > + Best regards, Krzysztof
