regulator: of: add support for allowed modes configuration

Add support for configuring the machine constraints
valid_modes_mask element based on a list of allowed modes
specified via a device tree property.
Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/of_regulator.c

@@ -32,7 +32,7 @@ static void of_get_regulation_constraints(struct device_node *np,
 	struct regulator_state *suspend_state;
 	struct device_node *suspend_np;
 	unsigned int mode;
-	int ret, i;
+	int ret, i, len;
 	u32 pval;
 
 	constraints->name = of_get_property(np, "regulator-name", NULL);
@@ -136,6 +136,33 @@ static void of_get_regulation_constraints(struct device_node *np,
 		}
 	}
 
+	len = of_property_count_elems_of_size(np, "regulator-allowed-modes",
+						sizeof(u32));
+	if (len > 0) {
+		if (desc && desc->of_map_mode) {
+			for (i = 0; i < len; i++) {
+				ret = of_property_read_u32_index(np,
+					"regulator-allowed-modes", i, &pval);
+				if (ret) {
+					pr_err("%s: couldn't read allowed modes index %d, ret=%d\n",
+						np->name, i, ret);
+					break;
+				}
+				mode = desc->of_map_mode(pval);
+				if (mode == REGULATOR_MODE_INVALID)
+					pr_err("%s: invalid regulator-allowed-modes element %u\n",
+						np->name, pval);
+				else
+					constraints->valid_modes_mask |= mode;
+			}
+			if (constraints->valid_modes_mask)
+				constraints->valid_ops_mask
+					|= REGULATOR_CHANGE_MODE;
+		} else {
+			pr_warn("%s: mode mapping not defined\n", np->name);
+		}
+	}
+
 	if (!of_property_read_u32(np, "regulator-system-load", &pval))
 		constraints->system_load = pval;