[PATCH v2 04/10] dt-bindings: soc: fsl: qe: Add support of IRQ in QE GPIO

[Paul Louvel <paul.louvel@bootlin.com>]

Some QE GPIO pins have an associated interrupt line in the QE PIC to
signal state changes on the pin.  Add the corresponding
interrupt-controller / nexus properties to the QE GPIO binding.

Because the GPIO controller does not perform any interrupt handling
itself, a nexus node (interrupt-map) is used to map each GPIO line
supporting IRQ to the parent QE PIC interrupt domain.

As the QE PIC can be configured to generate an interrupt on either a
high-to-low transition or any change in signal state, three
interrupt-map entries are needed per GPIO pin that can yield an
interrupt (falling, both, and the "none" case which defaults to both in
QE PIC).  This overhead is necessary because the interrupt-map-pass-thru
property is not part of the DT specification.

The interrupt-map property is optional: it is not required for GPIO
banks that have no interrupt capable GPIO line (e.g. port D on MPC8323),
or when interrupt functionality is not used.

Update the example to show a scenario where each bank supports a
different numbers of IRQs, or no IRQs at all.

Signed-off-by: Paul Louvel <paul.louvel@bootlin.com>
---
 .../bindings/gpio/fsl,mpc8323-qe-pario-bank.yaml   | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/fsl,mpc8323-qe-pario-bank.yaml b/Documentation/devicetree/bindings/gpio/fsl,mpc8323-qe-pario-bank.yaml
index 1af99339ff40..1d2ab44fcd3c 100644
--- a/Documentation/devicetree/bindings/gpio/fsl,mpc8323-qe-pario-bank.yaml
+++ b/Documentation/devicetree/bindings/gpio/fsl,mpc8323-qe-pario-bank.yaml
@@ -27,6 +27,17 @@ properties:
   "#gpio-cells":
     const: 2
 
+  "#address-cells":
+    const: 0
+
+  "#interrupt-cells":
+    const: 2
+
+  interrupt-map:
+    description: |
+      Specifies the mapping of GPIO lines to the parent interrupt controller, as the
+      GPIO controller does not do interrupt handling itself.
+
 required:
   - compatible
   - reg
@@ -37,9 +48,37 @@ additionalProperties: false
 
 examples:
   - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
     gpio-controller@1400 {
         compatible = "fsl,mpc8360-qe-pario-bank", "fsl,mpc8323-qe-pario-bank";
         reg = <0x1400 0x18>;
         gpio-controller;
         #gpio-cells = <2>;
     };
+
+    gpio-controller@1418 {
+        compatible = "fsl,mpc8323-qe-pario-bank";
+        reg = <0x1418 0x18>;
+        gpio-controller;
+        #gpio-cells = <2>;
+        #address-cells = <0>;
+        #interrupt-cells = <2>;
+        interrupt-map = <
+          7 IRQ_TYPE_EDGE_FALLING  &pic 4 IRQ_TYPE_EDGE_FALLING
+          7 IRQ_TYPE_EDGE_BOTH     &pic 4 IRQ_TYPE_EDGE_BOTH
+          7 0                      &pic 4 IRQ_TYPE_NONE
+
+          9 IRQ_TYPE_EDGE_FALLING  &pic 5 IRQ_TYPE_EDGE_FALLING
+          9 IRQ_TYPE_EDGE_BOTH     &pic 5 IRQ_TYPE_EDGE_BOTH
+          9 0                      &pic 5 IRQ_TYPE_NONE
+
+          25 IRQ_TYPE_EDGE_FALLING &pic 6 IRQ_TYPE_EDGE_FALLING
+          25 IRQ_TYPE_EDGE_BOTH    &pic 6 IRQ_TYPE_EDGE_BOTH
+          25 0                     &pic 6 IRQ_TYPE_NONE
+
+          27 IRQ_TYPE_EDGE_FALLING &pic 7 IRQ_TYPE_EDGE_FALLING
+          27 IRQ_TYPE_EDGE_BOTH    &pic 7 IRQ_TYPE_EDGE_BOTH
+          27 0                     &pic 7 IRQ_TYPE_NONE
+        >;
+    };

-- 
2.55.0