On 01/04/2022 15:50, AngeloGioacchino Del Regno wrote: > The syscon driver now enables the .fast_io regmap configuration when > the 'fast-io' property is found in a syscon node. > > Keeping in mind that, in regmap, fast_io is checked only if we are > not using hardware spinlocks, allow the fast-io property only if > there is no hwlocks reference (and vice-versa). I have doubts you need a property for this. "fast" is subjective in terms of hardware, so this looks more like a software property, not hardware. I think most of MMIOs inside a SoC are considered fast. Usually also the syscon/regmap consumer knows which regmap it gets, so knows that it is fast or not. > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/mfd/syscon.yaml | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.yaml b/Documentation/devicetree/bindings/mfd/syscon.yaml > index 13baa452cc9d..85a2e83b5861 100644 > --- a/Documentation/devicetree/bindings/mfd/syscon.yaml > +++ b/Documentation/devicetree/bindings/mfd/syscon.yaml > @@ -83,11 +83,26 @@ properties: > $ref: /schemas/types.yaml#/definitions/uint32 > enum: [1, 2, 4, 8] > > + fast-io: > + description: > + Indicates that this bus has a very fast IO, for which > + acquiring a mutex would be significant overhead. > + When present, regmap will use a spinlock instead. Regmap is current implementation behind this, but it's not related to hardware, so how about removing it from the description? Something like: "..., for which different locking methods should be used to reduce overhead (e.g. spinlock instead of mutex)." > + type: boolean > + > hwlocks: > maxItems: 1 > description: > Reference to a phandle of a hardware spinlock provider node. > > +if: > + required: > + - hwlocks > +then: > + not: > + required: > + - fast-io > + > required: > - compatible > - reg Best regards, Krzysztof
