of/irq: create interrupts-extended property

The standard interrupts property in device tree can only handle
interrupts coming from a single interrupt parent. If a device is wired
to multiple interrupt controllers, then it needs to be attached to a
node with an interrupt-map property to demux the interrupt specifiers
which is confusing. It would be a lot easier if there was a form of the
interrupts property that allows for a separate interrupt phandle for
each interrupt specifier.

This patch does exactly that by creating a new interrupts-extended
property which reuses the phandle+arguments pattern used by GPIOs and
other core bindings.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kumar Gala <galak@codeaurora.org>
[grant.likely: removed versatile platform hunks into separate patch]
Cc: Rob Herring <rob.herring@calxeda.com>

Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

@@ -4,16 +4,33 @@ Specifying interrupt information for devices
 1) Interrupt client nodes
 -------------------------
 
-Nodes that describe devices which generate interrupts must contain an
-"interrupts" property. This property must contain a list of interrupt
-specifiers, one per output interrupt. The format of the interrupt specifier is
-determined by the interrupt controller to which the interrupts are routed; see
-section 2 below for details.
+Nodes that describe devices which generate interrupts must contain an either an
+"interrupts" property or an "interrupts-extended" property. These properties
+contain a list of interrupt specifiers, one per output interrupt. The format of
+the interrupt specifier is determined by the interrupt controller to which the
+interrupts are routed; see section 2 below for details.
+
+  Example:
+	interrupt-parent = <&intc1>;
+	interrupts = <5 0>, <6 0>;
 
 The "interrupt-parent" property is used to specify the controller to which
 interrupts are routed and contains a single phandle referring to the interrupt
 controller node. This property is inherited, so it may be specified in an
-interrupt client node or in any of its parent nodes.
+interrupt client node or in any of its parent nodes. Interrupts listed in the
+"interrupts" property are always in reference to the node's interrupt parent.
+
+The "interrupts-extended" property is a special form for use when a node needs
+to reference multiple interrupt parents. Each entry in this property contains
+both the parent phandle and the interrupt specifier. "interrupts-extended"
+should only be used when a device has multiple interrupt parents.
+
+  Example:
+	interrupts-extended = <&intc1 5 1>, <&intc2 1 0>;
+
+A device node may contain either "interrupts" or "interrupts-extended", but not
+both. If both properties are present, then the operating system should log an
+error and use only the data in "interrupts".
 
 2) Interrupt controller nodes
 -----------------------------

arch/arm/boot/dts/testcases/tests-interrupts.dtsi

@@ -27,6 +27,12 @@
 						<4 &test_intc2 15 16>;
 			};
 
+			test_intmap1: intmap1 {
+				#interrupt-cells = <2>;
+				#address-cells = <0>;
+				interrupt-map = <1 2 &test_intc0 15>;
+			};
+
 			interrupts0 {
 				interrupt-parent = <&test_intc0>;
 				interrupts = <1>, <2>, <3>, <4>;
@@ -36,6 +42,16 @@
 				interrupt-parent = <&test_intmap0>;
 				interrupts = <1>, <2>, <3>, <4>;
 			};
+
+			interrupts-extended0 {
+				interrupts-extended = <&test_intc0 1>,
+						      <&test_intc1 2 3 4>,
+						      <&test_intc2 5 6>,
+						      <&test_intmap0 1>,
+						      <&test_intmap0 2>,
+						      <&test_intmap0 3>,
+						      <&test_intmap1 1 2>;
+			};
 		};
 	};
 };

drivers/of/irq.c

@@ -292,17 +292,23 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
 	if (of_irq_workarounds & OF_IMAP_OLDWORLD_MAC)
 		return of_irq_parse_oldworld(device, index, out_irq);
 
+	/* Get the reg property (if any) */
+	addr = of_get_property(device, "reg", NULL);
+
 	/* Get the interrupts property */
 	intspec = of_get_property(device, "interrupts", &intlen);
-	if (intspec == NULL)
-		return -EINVAL;
+	if (intspec == NULL) {
+		/* Try the new-style interrupts-extended */
+		res = of_parse_phandle_with_args(device, "interrupts-extended",
+						"#interrupt-cells", index, out_irq);
+		if (res)
+			return -EINVAL;
+		return of_irq_parse_raw(addr, out_irq);
+	}
 	intlen /= sizeof(*intspec);
 
 	pr_debug(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 
-	/* Get the reg property (if any) */
-	addr = of_get_property(device, "reg", NULL);
-
 	/* Look for the interrupt parent. */
 	p = of_irq_find_parent(device);
 	if (p == NULL)

drivers/of/selftest.c

@@ -231,6 +231,75 @@ static void __init of_selftest_parse_interrupts(void)
 	of_node_put(np);
 }
 
+static void __init of_selftest_parse_interrupts_extended(void)
+{
+	struct device_node *np;
+	struct of_phandle_args args;
+	int i, rc;
+
+	np = of_find_node_by_path("/testcase-data/interrupts/interrupts-extended0");
+	if (!np) {
+		pr_err("missing testcase data\n");
+		return;
+	}
+
+	for (i = 0; i < 7; i++) {
+		bool passed = true;
+		rc = of_irq_parse_one(np, i, &args);
+
+		/* Test the values from tests-phandle.dtsi */
+		switch (i) {
+		case 0:
+			passed &= !rc;
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 1);
+			break;
+		case 1:
+			passed &= !rc;
+			passed &= (args.args_count == 3);
+			passed &= (args.args[0] == 2);
+			passed &= (args.args[1] == 3);
+			passed &= (args.args[2] == 4);
+			break;
+		case 2:
+			passed &= !rc;
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == 5);
+			passed &= (args.args[1] == 6);
+			break;
+		case 3:
+			passed &= !rc;
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 9);
+			break;
+		case 4:
+			passed &= !rc;
+			passed &= (args.args_count == 3);
+			passed &= (args.args[0] == 10);
+			passed &= (args.args[1] == 11);
+			passed &= (args.args[2] == 12);
+			break;
+		case 5:
+			passed &= !rc;
+			passed &= (args.args_count == 2);
+			passed &= (args.args[0] == 13);
+			passed &= (args.args[1] == 14);
+			break;
+		case 6:
+			passed &= !rc;
+			passed &= (args.args_count == 1);
+			passed &= (args.args[0] == 15);
+			break;
+		default:
+			passed = false;
+		}
+
+		selftest(passed, "index %i - data error on node %s rc=%i\n",
+			 i, args.np->full_name, rc);
+	}
+	of_node_put(np);
+}
+
 static int __init of_selftest(void)
 {
 	struct device_node *np;
@@ -246,6 +315,7 @@ static int __init of_selftest(void)
 	of_selftest_parse_phandle_with_args();
 	of_selftest_property_match_string();
 	of_selftest_parse_interrupts();
+	of_selftest_parse_interrupts_extended();
 	pr_info("end of selftest - %i passed, %i failed\n",
 		selftest_results.passed, selftest_results.failed);
 	return 0;