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

On Fri, May 12, 2017 at 4:41 PM, Heiner Kallweit [off-list ref] wrote:

Am 12.05.2017 um 21:38 schrieb Rob Herring:

quoted

On Sun, May 07, 2017 at 06:34:09PM +0200, Heiner Kallweit wrote:

quoted

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 <redacted>
---
 .../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?

bindings/interrupt-controller

quoted

quoted

 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.

quoted

quoted

+- 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.

I would say an interrupt controller is anything that controls
routing/delivery of interrupts from source to cpu. This certainly
meets that criteria.

You could even use interrupt-map property to statically assign the
sources to parent interrupts.

Rob
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