Re: [PATCH] dt-bindings: mfd: Explain lack of child dependency in simple-mfd

From: Lee Jones
Date: Fri Jun 21 2024 - 07:10:13 EST


On Thu, 20 Jun 2024, Krzysztof Kozlowski wrote:

> On 20/06/2024 19:17, Lee Jones wrote:
> > On Sun, 16 Jun 2024, Krzysztof Kozlowski wrote:
> >
> >> Common mistake of usage of 'simple-mfd' compatible is a dependency of
> >> children on resources acquired and managed by the parent, e.g. clocks.
> >> Extend the simple-mfd documentation to cover this case.
> >>
> >> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> >> ---
> >> Documentation/devicetree/bindings/mfd/mfd.txt | 13 +++++++------
> >> 1 file changed, 7 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/mfd/mfd.txt b/Documentation/devicetree/bindings/mfd/mfd.txt
> >> index 336c0495c8a3..98b4340b65f3 100644
> >> --- a/Documentation/devicetree/bindings/mfd/mfd.txt
> >> +++ b/Documentation/devicetree/bindings/mfd/mfd.txt
> >> @@ -18,12 +18,13 @@ A typical MFD can be:
> >> Optional properties:
> >>
> >> - compatible : "simple-mfd" - this signifies that the operating system should
> >> - consider all subnodes of the MFD device as separate devices akin to how
> >> - "simple-bus" indicates when to see subnodes as children for a simple
> >> - memory-mapped bus. For more complex devices, when the nexus driver has to
> >> - probe registers to figure out what child devices exist etc, this should not
> >> - be used. In the latter case the child devices will be determined by the
> >> - operating system.
> >> + consider all subnodes of the MFD device as separate and independent devices
> >> + akin to how "simple-bus" indicates when to see subnodes as children for a
> >> + simple memory-mapped bus. "Independent devices" means that children do not
> >
> > I'm not against the change, but I think it can be phased better.
> >
> > Quoting the new part and going on to explain what you mean by it doesn't
> > flow very well. Are you able to massage it so it reads a little more
> > nicely please?
>
> Does this feels better?
>
> compatible : "simple-mfd" - this signifies that the operating system
> should consider all subnodes of the MFD device as separate and
> independent devices, so not needing any resources to be provided by the
> parent device. Similarly to how "simple-bus" indicates when to see
> subnodes as children for a simple memory-mapped bus.
>
> For more complex devices, when the nexus driver has to probe registers
> to figure out what child devices exist etc, this should not be used. In
> the latter case the child devices will be determined by the operating
> system.

Flows a lot better, yes.

Submit it and please include the original author this time.

--
Lee Jones [李琼斯]