regulator: Extend of_get_regulator_init_data to support non-DT consumers

Extend the of_get_regulator_init_data function so that it can
parse an additional property from regulator device tree nodes
which is needed to support non-device tree consumers.

The new property is named qcom,consumer-supplies.  Its value
is a list of strings of the form:

qcom,consumer-supplies = "supply_name1", "device_name1",
                         "supply_name2", "device_name2", ...

Change-Id: Ia689d04e6de568e6889b807eed15df3116de01d2
Signed-off-by: David Collins <collinsd@codeaurora.org>

Documentation/devicetree/bindings/regulator/regulator.txt

@@ -10,6 +10,11 @@ Optional properties:
 - regulator-always-on: boolean, regulator should never be disabled
 - regulator-boot-on: bootloader/firmware enabled regulator
 - <name>-supply: phandle to the parent supply/regulator node
+- qcom,consumer-supplies: flattened list of supply and dev_name pairs
+	This property is used to support regulator consumers that have no device
+	tree node.  An empty string, "", can be used to specify a null device
+	name.  A null device name is used to allow calls such as:
+	regulator_get(NULL, "pll_vdd").
 
 Example:
 
@@ -18,6 +23,7 @@ Example:
 		regulator-max-microvolt = <2500000>;
 		regulator-always-on;
 		vin-supply = <&vin>;
+		qcom,consumer-supplies = "pll_vdd", "", "lcd_vcc", "foo.1";
 	};
 
 Regulator Consumers:

drivers/regulator/of_regulator.c

@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/string.h>
 #include <linux/regulator/machine.h>
 
 static void of_get_regulation_constraints(struct device_node *np,
@@ -61,6 +62,71 @@ static void of_get_regulation_constraints(struct device_node *np,
 		constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;
 }
 
+static const char *consumer_supply_prop_name = "qcom,consumer-supplies";
+#define MAX_DEV_NAME_LEN 256
+/*
+ * Fill in regulator init_data based on qcom legacy requirements.
+ */
+static int of_get_qcom_regulator_init_data(struct device *dev,
+					struct regulator_init_data **init_data)
+{
+	struct device_node *node = dev->of_node;
+	struct regulator_consumer_supply *consumer_supplies;
+	int i, rc, num_consumer_supplies, array_len;
+
+	array_len = of_property_count_strings(node, consumer_supply_prop_name);
+	if (array_len > 0) {
+		/* Array length must be divisible by 2. */
+		if (array_len & 1) {
+			dev_err(dev, "error: %s device node property value "
+				"contains an odd number of elements: %d\n",
+				consumer_supply_prop_name, array_len);
+			return -EINVAL;
+		}
+		num_consumer_supplies = array_len / 2;
+
+		consumer_supplies = devm_kzalloc(dev,
+			sizeof(struct regulator_consumer_supply)
+			* num_consumer_supplies, GFP_KERNEL);
+		if (consumer_supplies == NULL) {
+			dev_err(dev, "devm_kzalloc failed\n");
+			return -ENOMEM;
+		}
+
+		for (i = 0; i < num_consumer_supplies; i++) {
+			rc = of_property_read_string_index(node,
+				consumer_supply_prop_name, i * 2,
+				&consumer_supplies[i].supply);
+			if (rc) {
+				dev_err(dev, "of_property_read_string_index "
+					"failed, rc=%d\n", rc);
+				devm_kfree(dev, consumer_supplies);
+				return rc;
+			}
+
+			rc = of_property_read_string_index(node,
+				consumer_supply_prop_name, (i * 2) + 1,
+				&consumer_supplies[i].dev_name);
+			if (rc) {
+				dev_err(dev, "of_property_read_string_index "
+					"failed, rc=%d\n", rc);
+				devm_kfree(dev, consumer_supplies);
+				return rc;
+			}
+
+			/* Treat dev_name = "" as a wildcard. */
+			if (strnlen(consumer_supplies[i].dev_name,
+					MAX_DEV_NAME_LEN) == 0)
+				consumer_supplies[i].dev_name = NULL;
+		}
+
+		(*init_data)->consumer_supplies = consumer_supplies;
+		(*init_data)->num_consumer_supplies = num_consumer_supplies;
+	}
+
+	return 0;
+}
+
 /**
  * of_get_regulator_init_data - extract regulator_init_data structure info
  * @dev: device requesting for regulator_init_data
@@ -73,6 +139,7 @@ struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
 						struct device_node *node)
 {
 	struct regulator_init_data *init_data;
+	int rc;
 
 	if (!node)
 		return NULL;
@@ -82,6 +149,12 @@ struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
 		return NULL; /* Out of memory? */
 
 	of_get_regulation_constraints(node, &init_data);
+	rc = of_get_qcom_regulator_init_data(dev, &init_data);
+	if (rc) {
+		devm_kfree(dev, init_data);
+		return NULL;
+	}
+
 	return init_data;
 }
 EXPORT_SYMBOL_GPL(of_get_regulator_init_data);