Merge branch 'opp/empty' into opp/linux-next

2 files changed, 58 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
index 9847dfeeffcb..08b3da4736cf 100644
--- a/Documentation/devicetree/bindings/opp/opp.txt
+++ b/Documentation/devicetree/bindings/opp/opp.txt
@@ -65,7 +65,9 @@ Required properties:
 
 - OPP nodes: One or more OPP nodes describing voltage-current-frequency
   combinations. Their name isn't significant but their phandle can be used to
-  reference an OPP.
+  reference an OPP. These are mandatory except for the case where the OPP table
+  is present only to indicate dependency between devices using the opp-shared
+  property.
 
 Optional properties:
 - opp-shared: Indicates that device nodes using this OPP Table Node's phandle
@@ -568,3 +570,53 @@ Example 6: opp-microvolt-<name>, opp-microamp-<name>:
 		};
 	};
 };
+
+Example 7: Single cluster Quad-core ARM cortex A53, OPP points from firmware,
+distinct clock controls but two sets of clock/voltage/current lines.
+
+/ {
+	cpus {
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x100>;
+			next-level-cache = <&A53_L2>;
+			clocks = <&dvfs_controller 0>;
+			operating-points-v2 = <&cpu_opp0_table>;
+		};
+		cpu@1 {
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x101>;
+			next-level-cache = <&A53_L2>;
+			clocks = <&dvfs_controller 1>;
+			operating-points-v2 = <&cpu_opp0_table>;
+		};
+		cpu@2 {
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x102>;
+			next-level-cache = <&A53_L2>;
+			clocks = <&dvfs_controller 2>;
+			operating-points-v2 = <&cpu_opp1_table>;
+		};
+		cpu@3 {
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x103>;
+			next-level-cache = <&A53_L2>;
+			clocks = <&dvfs_controller 3>;
+			operating-points-v2 = <&cpu_opp1_table>;
+		};
+
+	};
+
+	cpu_opp0_table: opp0_table {
+		compatible = "operating-points-v2";
+		opp-shared;
+	};
+
+	cpu_opp1_table: opp1_table {
+		compatible = "operating-points-v2";
+		opp-shared;
+	};
+};
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 6b7f0066942d..d41088578aab 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -170,7 +170,8 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
 	/* Traversing the first OPP node is all we need */
 	np = of_get_next_available_child(opp_np, NULL);
 	if (!np) {
-		dev_err(dev, "Empty OPP table\n");
+		dev_warn(dev, "Empty OPP table\n");
+
 		return;
 	}
 
@@ -378,7 +379,9 @@ int dev_pm_opp_of_find_icc_paths(struct device *dev,
 	struct icc_path **paths;
 
 	ret = _bandwidth_supported(dev, opp_table);
-	if (ret <= 0)
+	if (ret == -EINVAL)
+		return 0; /* Empty OPP table is a valid corner-case, let's not fail */
+	else if (ret <= 0)
 		return ret;
 
 	ret = 0;