[PATCH 2/5] pintrl: meson: document GPIO IRQ DT binding

[hkallweit1@gmail.com (Heiner Kallweit)]

Am 12.05.2017 um 21:38 schrieb Rob Herring:
> On Sun, May 07, 2017 at 06:34:09PM +0200, Heiner Kallweit wrote:
>> Document the DT binding for GPIO IRQ support on Amlogic Meson SoC's.
>>
>> This documentation is intentionally not placed under
>> interrupt-controllers as GPIO IRQ support on these SoC's acts more
>> like an interrupt multiplexer.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
>>  .../bindings/gpio/amlogic,meson-gpio-interrupt.txt | 30 ++++++++++++++++++++++
> 
> Seems more like an irqchip?
> 
It is an irq_chip. Would you therefore prefer a different name or another location
for this binding documentation?

>>  1 file changed, 30 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/gpio/amlogic,meson-gpio-interrupt.txt
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/amlogic,meson-gpio-interrupt.txt b/Documentation/devicetree/bindings/gpio/amlogic,meson-gpio-interrupt.txt
>> new file mode 100644
>> index 00000000..35a052b8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/gpio/amlogic,meson-gpio-interrupt.txt
>> @@ -0,0 +1,30 @@
>> +Amlogic meson GPIO interrupt controller
>> +
>> +Meson SoCs contains an interrupt controller which is able watch the SoC pads
>> +and generate an interrupt on edges or level. The controller is essentially a
>> +256 pads to 8 GIC interrupt multiplexer, with a filter block to select edge
>> +or level and polarity. We don't expose all 256 mux inputs because the
>> +documentation shows that upper part is not mapped to any pad. The actual number
>> +of interrupt exposed depends on the SoC.
>> +
>> +Required properties:
>> +
>> +- compatible : should be "amlogic,meson-gpio-interrupt", "syscon".
> 
> Why syscon?
> 
Has been removed already in v2 of the patch.

>> +- reg : Specifies base physical address and size of the registers.
>> +- interrupts : list of GIC interrupts which can be used with the
>> +	       GPIO IRQ multiplexer
> 
> What about interrupt-controller property?
> 
This HW is somewhat special, it's more or less a multiplexer between
100+ GPIO's and 8 GIC IRQ's. And we have two GPIO domains, both having
a "gpio-controller".
It doesn't seem that the "interrupt-controller" property is right here.
I'd tend to say it should be added to the "gpio-controller" nodes.

>> +
>> +Example:
>> +
>> +gpio_irq at 9880 {
> 
> interrupt-controller at ...
> 
This relates to previous comment, as it isn't really an interrupt
controller I'm not sure we should use this name.

>> +	compatible = "amlogic,meson-gpio-interrupt", "syscon";
>> +	reg = <0x0 0x09880 0x0 0x10>;
>> +	interrupts = <GIC_SPI 64 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 65 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 66 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 67 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 68 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 69 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 70 IRQ_TYPE_NONE>,
>> +		     <GIC_SPI 71 IRQ_TYPE_NONE>;
>> +	};
>> -- 
>> 2.12.2
>>
>>
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>