[PATCH v3 4/4] regulator: map consumer regulator based on device tree

From: Rajendra Nayak
Date: Thu Oct 27 2011 - 03:59:55 EST

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@xxxxxx>
Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
---
drivers/regulator/core.c | 79 ++++++++++++++++++++++++++++++++------
include/linux/regulator/driver.h | 2 +
2 files changed, 69 insertions(+), 12 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 6edaaf0..36fc0b0 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -25,9 +25,11 @@
#include <linux/mutex.h>
#include <linux/suspend.h>
#include <linux/delay.h>
+#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>

#define CREATE_TRACE_POINTS
#include <trace/events/regulator.h>
@@ -131,6 +133,33 @@ 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)
@@ -1147,6 +1176,30 @@ 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)
@@ -1167,6 +1220,10 @@ 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 &&
@@ -2579,6 +2636,7 @@ 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;

if (regulator_desc == NULL)
return ERR_PTR(-EINVAL);
@@ -2654,21 +2712,18 @@ 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;
}
diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 461eb90..87a121c 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -153,6 +153,7 @@ enum regulator_type {
* this type.
*
* @name: Identifying name for the regulator.
+ * @supply_name: Identifying the regulator supply
* @id: Numerical identifier for the regulator.
* @n_voltages: Number of selectors available for ops.list_voltage().
* @ops: Regulator operations table.
@@ -162,6 +163,7 @@ enum regulator_type {
*/
struct regulator_desc {
const char *name;
+ const char *supply_name;
int id;
unsigned n_voltages;
struct regulator_ops *ops;
--
1.7.1

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