Re: [PATCH RFC v2 2/3] dt-bindings/interrupt-controller: pdc: descibe PDC device binding

[Lina Iyer]

On Fri, Feb 02 2018 at 16:28 +0000, Marc Zyngier wrote:
> On 02/02/18 14:21, Lina Iyer wrote:
> > From: Archana Sathyakumar <asathyak@xxxxxxxxxxxxxx>
> >
> > Add device binding documentation for the PDC Interrupt controller on
> > QCOM SoC's like the SDM845. The interrupt-controller can be used to
> > sense edge low interrupts and wakeup interrupts when the GIC is
> > non-operational.
> >
> > Cc: devicetree@xxxxxxxxxxxxxxx
> > Signed-off-by: Archana Sathyakumar <asathyak@xxxxxxxxxxxxxx>
> > Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> > ---
> >  .../bindings/interrupt-controller/qcom,pdc.txt     | 78 ++++++++++++++++++++++
> >  1 file changed, 78 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/qcom,pdc.txt
> >
> > diff --git a/Documentation/devicetree/bindings/interrupt-controller/qcom,pdc.txt b/Documentation/devicetree/bindings/interrupt-controller/qcom,pdc.txt
> > new file mode 100644
> > index 000000000000..7bf40cb6a4f8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/interrupt-controller/qcom,pdc.txt
> > @@ -0,0 +1,78 @@
> > +PDC interrupt controller
> > +
> > +Qualcomm Technologies Inc. SoCs based on the RPM Hardened architecture have a
> > +Power Domain Controller (PDC) that is on always-on domain. In addition to
> > +providing power control for the power domains, the hardware also has an
> > +interrupt controller that can be used to help detect edge low interrupts as
> > +well detect interrupts when the GIC is non-operational.
> > +
> > +GIC is parent interrupt controller at the highest level. Platform interrupt
> > +controller PDC is next in hierarchy, followed by others. Drivers requiring
> > +wakeup capabilities of their device interrupts routed through the PDC, must
> > +specify PDC as their interrupt controller and request the PDC port associated
> > +with the GIC interrupt. See example below.
> > +
> > +Properties:
> > +
> > +- compatible:
> > +	Usage: required
> > +	Value type: <string>
> > +	Definition: Should contain "qcom,<soc>-pdc"
> > +		    - "qcom,sdm845-pdc": For SDM845
> > +
> > +- reg:
> > +	Usage: required
> > +	Value type: <prop-encoded-array>
> > +	Definition: Specifies the base physical address for PDC hardware.
> > +
> > +- interrupt-cells:
> > +	Usage: required
> > +	Value type: <u32>
> > +	Definition: Specifies the number of cells needed to encode an interrupt
> > +		    source.
> > +		    The value must match that of the parent interrupt
> > +		    controller defined in the DT.
> > +		    The encoding of these cells are same as described in [1].
>
> There shouldn't be such a requirement. These are two independent pieces
> of HW, and the first parameter doesn't mean anything for the PDC.
Wouldn't that be confusing - that we have different definitions for
interrupts in the same DT? I agree that they are different interrupt
controllers, but it just feels odd.

I will change this to just take 2 cells.

> > +
> > +- interrupt-parent:
> > +	Usage: required
> > +	Value type: <phandle>
> > +	Definition: Specifies the interrupt parent necessary for hierarchical
> > +		    domain to operate.
> > +
> > +- interrupt-controller:
> > +	Usage: required
> > +	Value type: <bool>
> > +	Definition: Identifies the node as an interrupt controller.
> > +
> > +- qcom,pdc-range:
> > +	Usage: required
> > +	Value type: <u32 array>
> > +	Definition: Specifies the PDC pin offset and the number of PDC ports.
> > +		    The tuples indicates the valid mapping of valid PDC ports
> > +		    and their hwirq mapping.
> > +		    The first element of the tuple is the staring PDC port num.
> > +		    The second element is the hwirq number for the PDC port.
> > +		    The third element is the number of elements in sequence.
> > +
> > +Example:
> > +
> > +	pdc: interrupt-controller@b220000 {
> > +		compatible = "qcom,sdm845-pdc";
> > +		reg = <0xb220000 0x30000>;
> > +		qcom,pdc-ranges = <0 512 94>, <94 641 15>, <115 662 7>;
> > +		#interrupt-cells = <3>;
> > +		interrupt-parent = <&intc>;
> > +		interrupt-controller;
> > +	};
> > +
> > +The DT binding of a device that wants to use the GIC SPI 514 as a wakeup
> > +interrupt, would look like this -
> > +
> > +	wake-device {
> > +		[...]
> > +		interrupt-parent = <&pdc>;
> > +		interrupt = <0 2 0>;
>
> Again: 0 is not a valid trigger value.
Ok.

Thanks,
Lina