regulator: map consumer regulator based on device tree

Device nodes in DT can associate themselves with one or more
regulators/supply by providing a list of phandles (to regulator nodes)
and corresponding supply names.

For Example:
	devicenode: node@0x0 {
		...
		...
		vmmc-supply = <&regulator1>;
		vpll-supply = <&regulator2>;
	};

The driver would then do a regulator_get(dev, "vmmc"); to get
regulator1 and do a regulator_get(dev, "vpll"); to get
regulator2.

of_get_regulator() extracts the regulator node for a given
device, based on the supply name.

Use it to look up the regulator for a given consumer from device tree, during
a regulator_get(). If not found fallback and lookup through
the regulator_map_list instead.

Also, since the regulator dt nodes can use the same binding to
associate with a parent regulator/supply, allow the drivers to
specify a supply_name, which can then be used to lookup dt
to find the parent phandle.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 67 insertions, 12 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 8b01eb06ba64..9867ebc00bed 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -25,6 +25,8 @@
 #include <linux/mutex.h>
 #include <linux/suspend.h>
 #include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/regulator/of_regulator.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
@@ -132,6 +134,33 @@ static struct regulator *get_device_regulator(struct device *dev)
         return NULL;
 }
 
+/**
+ * of_get_regulator - get a regulator device node based on supply name
+ * @dev: Device pointer for the consumer (of regulator) device
+ * @supply: regulator supply name
+ *
+ * Extract the regulator device node corresponding to the supply name.
+ * retruns the device node corresponding to the regulator if found, else
+ * returns NULL.
+ */
+static struct device_node *of_get_regulator(struct device *dev, const char *supply)
+{
+        struct device_node *regnode = NULL;
+        char prop_name[32]; /* 32 is max size of property name */
+
+        dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);
+
+        snprintf(prop_name, 32, "%s-supply", supply);
+        regnode = of_parse_phandle(dev->of_node, prop_name, 0);
+
+        if (!regnode) {
+                dev_warn(dev, "%s property in node %s references invalid phandle",
+                                prop_name, dev->of_node->full_name);
+                return NULL;
+        }
+        return regnode;
+}
+
 /* Platform voltage constraint check */
 static int regulator_check_voltage(struct regulator_dev *rdev,
                                    int *min_uV, int *max_uV)
@@ -1148,6 +1177,30 @@ static int _regulator_get_enable_time(struct regulator_dev *rdev)
         return rdev->desc->ops->enable_time(rdev);
 }
 
+static struct regulator_dev *regulator_dev_lookup(struct device *dev,
+                                                         const char *supply)
+{
+        struct regulator_dev *r;
+        struct device_node *node;
+
+        /* first do a dt based lookup */
+        if (dev && dev->of_node) {
+                node = of_get_regulator(dev, supply);
+                if (node)
+                        list_for_each_entry(r, &regulator_list, list)
+                                if (r->dev.parent &&
+                                        node == r->dev.of_node)
+                                        return r;
+        }
+
+        /* if not found, try doing it non-dt way */
+        list_for_each_entry(r, &regulator_list, list)
+                if (strcmp(rdev_get_name(r), supply) == 0)
+                        return r;
+
+        return NULL;
+}
+
 /* Internal regulator request function */
 static struct regulator *_regulator_get(struct device *dev, const char *id,
                                         int exclusive)
@@ -1168,6 +1221,10 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
 
         mutex_lock(&regulator_list_mutex);
 
+        rdev = regulator_dev_lookup(dev, id);
+        if (rdev)
+                goto found;
+
         list_for_each_entry(map, &regulator_map_list, list) {
                 /* If the mapping has a device set up it must match */
                 if (map->dev_name &&
@@ -2642,6 +2699,7 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
         static atomic_t regulator_no = ATOMIC_INIT(0);
         struct regulator_dev *rdev;
         int ret, i;
+        const char *supply = NULL;
 
         if (regulator_desc == NULL)
                 return ERR_PTR(-EINVAL);
@@ -2718,21 +2776,18 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
         if (ret < 0)
                 goto scrub;
 
-        if (init_data->supply_regulator) {
+        if (init_data->supply_regulator)
+                supply = init_data->supply_regulator;
+        else if (regulator_desc->supply_name)
+                supply = regulator_desc->supply_name;
+
+        if (supply) {
                 struct regulator_dev *r;
-                int found = 0;
 
-                list_for_each_entry(r, &regulator_list, list) {
-                        if (strcmp(rdev_get_name(r),
-                                   init_data->supply_regulator) == 0) {
-                                found = 1;
-                                break;
-                        }
-                }
+                r = regulator_dev_lookup(dev, supply);
 
-                if (!found) {
-                        dev_err(dev, "Failed to find supply %s\n",
-                                init_data->supply_regulator);
+                if (!r) {
+                        dev_err(dev, "Failed to find supply %s\n", supply);
                         ret = -ENODEV;
                         goto scrub;
                 }