Re: [PATCH v2 06/10] dt-bindings: irqchip: Introduce TISCI Interrupt router bindings

[Rob Herring <robh@kernel.org>]

On Thu, Oct 18, 2018 at 09:10:13PM +0530, Lokesh Vutla wrote:
> Add the DT binding documentation for Interrupt router driver.
> 
> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
> ---
> Changes since v1:
> - Drop dependency on GIC
> - Updated supported interrupt types.
> 
>  .../interrupt-controller/ti,sci-intr.txt      | 81 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
> new file mode 100644
> index 000000000000..276bb4f0ad12
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
> @@ -0,0 +1,81 @@
> +Texas Instruments K3 Interrupt Router
> +=====================================
> +
> +The Interrupt Router (INTR) module provides a mechanism to mux M
> +interrupt inputs to N interrupt outputs, where all M inputs are selectable
> +to be driven per N output. There is one register per output (MUXCNTL_N) that
> +controls the selection.
> +
> +
> +                                 Interrupt Router
> +                             +----------------------+
> +                             |  Inputs     Outputs  |
> +        +-------+            | +------+             |
> +        | GPIO  |----------->| | irq0 |             |       Host IRQ
> +        +-------+            | +------+             |      controller
> +                             |    .        +-----+  |      +-------+
> +        +-------+            |    .        |  0  |  |----->|  IRQ  |
> +        | INTA  |----------->|    .        +-----+  |      +-------+
> +        +-------+            |    .          .      |
> +                             | +------+      .      |
> +                             | | irqM |    +-----+  |
> +                             | +------+    |  N  |  |
> +                             |             +-----+  |
> +                             +----------------------+
> +
> +Configuration of these MUXCNTL_N registers is done by a system controller
> +(like the Device Memory and Security Controller on K3 AM654 SoC). System
> +controller will keep track of the used and unused registers within the Router.
> +Driver should request the system controller to get the range of GIC IRQs
> +assigned to the requesting hosts. It is the drivers responsibility to keep
> +track of Host IRQs.
> +
> +Communication between the host processor running an OS and the system
> +controller happens through a protocol called TI System Control Interface
> +(TISCI protocol). For more details refer:
> +Documentation/devicetree/bindings/arm/keystone/ti,sci.txt
> +
> +TISCI Interrupt Router Node:
> +----------------------------
> +- compatible:		Must be "ti,sci-intr".
> +- interrupt-controller:	Identifies the node as an interrupt controller
> +- #interrupt-cells:	Specifies the number of cells needed to encode an
> +			interrupt source. The value should be 3.
> +			First cell should contain the TISCI device ID of source
> +			Second cell should contain the interrupt source offset
> +			within the device
> +			Third cell specifies the trigger type as defined
> +			in interrupts.txt in this directory. Only level
> +			sensitive trigger types are supported.
> +- interrupt-parent:	phandle of irq parent for TISCI intr.

This is implied and could be in a parent node.

> +- ti,sci:		Phandle to TI-SCI compatible System controller node.
> +- ti,sci-dst-id:	TISCI device ID of the destination IRQ controller.
> +- ti,sci-rm-range-girq:	TISCI subtype id representing the host irqs assigned
> +			to this interrupt router.

These need a better explanation and there's still some questions on v1 
asked of me that I tried to answer.

> +
> +Example:
> +--------
> +The following example demonstrates both interrupt router node and the consumer
> +node(main gpio) on the AM654 SoC:
> +
> +main_intr: interrupt-controller@1 {
> +	compatible = "ti,sci-intr";
> +	interrupt-controller;
> +	interrupt-parent = <&gic>;
> +	#interrupt-cells = <3>;
> +	ti,sci = <&dmsc>;
> +	ti,sci-dst-id = <56>;
> +	ti,sci-rm-range-girq = <0x1>;
> +};
> +
> +main_gpio0:  main_gpio0@600000 {

gpio@...

> +	...
> +	interrupt-parent = <&main_intr>;
> +	interrupts = <57 256 IRQ_TYPE_EDGE_RISING>,
> +			<57 257 IRQ_TYPE_EDGE_RISING>,
> +			<57 258 IRQ_TYPE_EDGE_RISING>,
> +			<57 259 IRQ_TYPE_EDGE_RISING>,
> +			<57 260 IRQ_TYPE_EDGE_RISING>,
> +			<57 261 IRQ_TYPE_EDGE_RISING>;
> +	...
> +};
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 06966772cad4..710cf728b9d0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14686,6 +14686,7 @@ F:	Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>  F:	Documentation/devicetree/bindings/clock/ti,sci-clk.txt
>  F:	drivers/clk/keystone/sci-clk.c
>  F:	drivers/reset/reset-ti-sci.c
> +F:	Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>  
>  THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
>  M:	Hans Verkuil <hverkuil@xs4all.nl>
> -- 
> 2.19.1
>