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

From: Marc Zyngier
Date: Fri Feb 02 2018 - 11:28:22 EST


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.

> +
> +- 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.

> + };
> +
> +[1]. Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
>

Thanks,

M.
--
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