Re: [RFC PATCH 1/2] dt-bindings: irqchip: Update bindings to drop the usage of gic as parent

[Lokesh Vutla <lokeshvutla@ti.com>]

Hi Marc,

On 02/10/19 6:27 PM, Marc Zyngier wrote:
> On Mon, 23 Sep 2019 09:54:04 +0530
> Lokesh Vutla <lokeshvutla@ti.com> wrote:
> 
>> Drop the firmware related dt-bindings and use the hardware specified
>> interrupt numbers within Interrupt Router. This ensures interrupt router
>> DT node need not assume any interrupt parent type.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>>  .../interrupt-controller/ti,sci-intr.txt      | 28 +++++++++----------
>>  1 file changed, 13 insertions(+), 15 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>> index 1a8718f8855d..de5de2a4b467 100644
>> --- a/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>> +++ b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>> @@ -44,15 +44,14 @@ Required Properties:
>>  			4: If intr supports level triggered interrupts.
>>  - 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 2.
>> -			First cell should contain the TISCI device ID of source
>> -			Second cell should contain the interrupt source offset
>> -			within the device.
>> +			interrupt source. The value should be 1.
>> +			First cell should contain interrupt router input number
>> +			as specified by hardware.
> 
> This is breaking compatibility with existing kernels. Why isn't that a
> problem?

Yes, I am not denying that backward compatibility is broken. But I feel this is
a good cleanup for representing INTR interrupts. With this child nodes will pass
the INTR specific number rather the device specific offset. Actually I tried
following as what GIC is representing.

As there are only two users upstreamed, I though it is better to clean it up
asap. Do you prefer maintaining the existing usage with a different compatible?


> 
>> +- power-domains:	phandle pointing to the corresponding PM domain node
>> +			and an ID representing the device.
> 
> Why is this power-domain thing part of this patch? Is it related?
> 
>>  - 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:	Array of TISCI subtype ids representing the host irqs
>> -			assigned to this interrupt router. Each subtype id
>> -			corresponds to a range of host irqs.
>> +- interrupt-ranges:	Ranges that convert the INTR output interrupt numbers to
>> +			parent's interrupt number.
> 
> This isn't a standard property, is it? If it isn't, it should be
> documented a bit more than just that.

Nope. Ill update it. So, the reason this is added is that this ranges converts
the output of INTR to parent interrupt number. This is to have consistent dt
convention in the following 2 scenarios:
- INTR -> GIC (GIC is parent of INTR)
- INTR -> INTR (INTR is parent of INTR)

Thanks and regards,
Lokesh

> 
>>  
>>  For more details on TISCI IRQ resource management refer:
>>  http://downloads.ti.com/tisci/esd/latest/2_tisci_msgs/rm/rm_irq.html
>> @@ -62,21 +61,20 @@ Example:
>>  The following example demonstrates both interrupt router node and the consumer
>>  node(main gpio) on the AM654 SoC:
>>  
>> -main_intr: interrupt-controller0 {
>> +main_gpio_intr: interrupt-controller0 {
>>  	compatible = "ti,sci-intr";
>>  	ti,intr-trigger-type = <1>;
>>  	interrupt-controller;
>>  	interrupt-parent = <&gic500>;
>> -	#interrupt-cells = <2>;
>> +	power-domains = <&k3_pds 131 TI_SCI_PD_SHARED>;
>> +	#interrupt-cells = <1>;
>>  	ti,sci = <&dmsc>;
>> -	ti,sci-dst-id = <56>;
>> -	ti,sci-rm-range-girq = <0x1>;
>> +	interrupt-ranges = <0 360 32>;
>>  };
>>  
>>  main_gpio0: gpio@600000 {
>>  	...
>> -	interrupt-parent = <&main_intr>;
>> -	interrupts = <57 256>, <57 257>, <57 258>,
>> -		     <57 259>, <57 260>, <57 261>;
>> +	interrupt-parent = <&main_gpio_intr>;
>> +	interrupts = <192>, <193>, <194>, <195>, <196>, <197>;
>>  	...
>>  };
> 
> Thanks,
> 
> 	M.
> 

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