Re: [RFC PATCH v2 02/31] Documentation: Add binding for kalray,kv3-1-core-intc

[Jules Maselbas]

Hi Krzysztof,

On Sun, Jan 22, 2023 at 12:44:46PM +0100, Krzysztof Kozlowski wrote:
> On 20/01/2023 15:09, Yann Sionneau wrote:
> > From: Jules Maselbas <jmaselbas@xxxxxxxxx>
> 
> Use subject prefixes matching the subsystem (which you can get for
> example with `git log --oneline -- DIRECTORY_OR_FILE` on the directory
> your patch is touching).
This will be fixed, sorry for the inconvenience.

> 
> > 
> > Add documentation for `kalray,kv3-1-core-intc` binding.
> > 
> > Co-developed-by: Jules Maselbas <jmaselbas@xxxxxxxxx>
> > Signed-off-by: Jules Maselbas <jmaselbas@xxxxxxxxx>
> > Signed-off-by: Yann Sionneau <ysionneau@xxxxxxxxx>
> > ---
> > 
> > Notes:
> >     V1 -> V2: new patch
> > 
> >  .../kalray,kv3-1-core-intc.yaml               | 46 +++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/kalray,kv3-1-core-intc.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/interrupt-controller/kalray,kv3-1-core-intc.yaml b/Documentation/devicetree/bindings/interrupt-controller/kalray,kv3-1-core-intc.yaml
> > new file mode 100644
> > index 000000000000..1e3d0593173a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/interrupt-controller/kalray,kv3-1-core-intc.yaml
> > @@ -0,0 +1,46 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/interrupt-controller/kalray,kv3-1-core-intc#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Kalray kv3-1 Core Interrupt Controller
> > +
> > +description: |
> > +  The Kalray Core Interrupt Controller is tightly integrated in each kv3 core
> > +  present in the Coolidge SoC.
> > +
> > +  It provides the following features:
> > +  - 32 independent interrupt sources
> > +  - 2-bit configurable priority level
> > +  - 2-bit configurable ownership level
> > +
> > +allOf:
> > +  - $ref: /schemas/interrupt-controller.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: kalray,kv3-1-core-intc
> 
> Blank line between each of these,
Ack

> > +  "#interrupt-cells":
> > +    const: 1
> > +    description:
> > +      The IRQ number.
> > +  reg:
> > +    maxItems: 0
> 
> ??? No way... What's this?
This (per CPU) interrupt controller is not memory mapped at all, it is
controlled and configured through system registers.

I do not have found existing .yaml bindings for such devices, only the
file snps,archs-intc.txt has something similar.

I do not know what is the best way to represent such devices in the
device-tree.  Any suggestions are welcome.

> 
> > +  "kalray,intc-nr-irqs":
> 
> Drop quotes.
> 
> > +    description: Number of irqs handled by the controller.
> 
> Why this is variable per board? Why do you need it ?
This property is not even used in our device-tree, this will be removed
from the documentation and from the driver as well.

> > +
> > +required:
> > +  - compatible
> > +  - "#interrupt-cells"
> > +  - interrupt-controller
> 
> missing additionalProperties: false
> 
> This binding looks poor, like you started from something odd. Please
> don't. Take the newest reviewed binding or better example-schema and use
> it to build yours. This would solve several trivial mistakes and style
> issues.
I am starting over from the example-schema.

> > +
> > +examples:
> > +  - |
> > +    intc: interrupt-controller {
> 
> What's the IO address space?
As said above, this is not a memory mapped device, but is accessed
through system registers.

Thanks,
-- Jules