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Subject[PATCH V3 01/16] PM / OPP: get/put regulators from OPP core
Date
This allows the OPP core to request/free the regulator resource,
attached to a device OPP. The regulator device is fetched using the name
provided by the driver, while calling: dev_pm_opp_set_regulator().

This will work for both OPP-v1 and v2 bindings.

This is a preliminary step for moving the OPP switching logic into the
OPP core.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp/core.c | 111 ++++++++++++++++++++++++++++++++++++++++++
drivers/base/power/opp/opp.h | 4 ++
include/linux/pm_opp.h | 9 ++++
3 files changed, 124 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index cf351d3dab1c..1e22b71abf1e 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -19,6 +19,7 @@
#include <linux/device.h>
#include <linux/of.h>
#include <linux/export.h>
+#include <linux/regulator/consumer.h>

#include "opp.h"

@@ -565,6 +566,9 @@ static void _remove_device_opp(struct device_opp *dev_opp)
if (dev_opp->prop_name)
return;

+ if (!IS_ERR_OR_NULL(dev_opp->regulator))
+ return;
+
list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,
node);

@@ -1085,6 +1089,113 @@ void dev_pm_opp_put_prop_name(struct device *dev)
}
EXPORT_SYMBOL_GPL(dev_pm_opp_put_prop_name);

+/**
+ * dev_pm_opp_set_regulator() - Set regulator name for the device
+ * @dev: Device for which regulator name is being set.
+ * @name: Name of the regulator.
+ *
+ * In order to support OPP switching, OPP layer needs to know the name of the
+ * device's regulator, as the core would be required to switch voltages as well.
+ *
+ * This must be called before any OPPs are initialized for the device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ */
+int dev_pm_opp_set_regulator(struct device *dev, const char *name)
+{
+ struct device_opp *dev_opp;
+ struct regulator *reg;
+ int ret;
+
+ mutex_lock(&dev_opp_list_lock);
+
+ dev_opp = _add_device_opp(dev);
+ if (!dev_opp) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ /* This should be called before OPPs are initialized */
+ if (WARN_ON(!list_empty(&dev_opp->opp_list))) {
+ ret = -EBUSY;
+ goto err;
+ }
+
+ /* Already have a regulator set */
+ if (WARN_ON(!IS_ERR_OR_NULL(dev_opp->regulator))) {
+ ret = -EBUSY;
+ goto err;
+ }
+ /* Allocate the regulator */
+ reg = regulator_get_optional(dev, name);
+ if (IS_ERR(reg)) {
+ ret = PTR_ERR(reg);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "%s: no regulator (%s) found: %d\n",
+ __func__, name, ret);
+ goto err;
+ }
+
+ dev_opp->regulator = reg;
+
+ mutex_unlock(&dev_opp_list_lock);
+ return 0;
+
+err:
+ _remove_device_opp(dev_opp);
+unlock:
+ mutex_unlock(&dev_opp_list_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulator);
+
+/**
+ * dev_pm_opp_put_regulator() - Releases resources blocked for regulator
+ * @dev: Device for which regulator was set.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ */
+void dev_pm_opp_put_regulator(struct device *dev)
+{
+ struct device_opp *dev_opp;
+
+ mutex_lock(&dev_opp_list_lock);
+
+ /* Check for existing list for 'dev' first */
+ dev_opp = _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ dev_err(dev, "Failed to find dev_opp: %ld\n", PTR_ERR(dev_opp));
+ goto unlock;
+ }
+
+ if (IS_ERR_OR_NULL(dev_opp->regulator)) {
+ dev_err(dev, "%s: Doesn't have regulator set\n", __func__);
+ goto unlock;
+ }
+
+ /* Make sure there are no concurrent readers while updating dev_opp */
+ WARN_ON(!list_empty(&dev_opp->opp_list));
+
+ regulator_put(dev_opp->regulator);
+ dev_opp->regulator = ERR_PTR(-EINVAL);
+
+ /* Try freeing device_opp if this was the last blocking resource */
+ _remove_device_opp(dev_opp);
+
+unlock:
+ mutex_unlock(&dev_opp_list_lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulator);
+
static bool _opp_is_supported(struct device *dev, struct device_opp *dev_opp,
struct device_node *np)
{
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 690638ef36ee..416293b7da23 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -22,6 +22,8 @@
#include <linux/rculist.h>
#include <linux/rcupdate.h>

+struct regulator;
+
/* Lock to allow exclusive modification to the device and opp lists */
extern struct mutex dev_opp_list_lock;

@@ -132,6 +134,7 @@ struct device_list_opp {
* @supported_hw: Array of version number to support.
* @supported_hw_count: Number of elements in supported_hw array.
* @prop_name: A name to postfix to many DT properties, while parsing them.
+ * @regulator: Supply regulator
* @dentry: debugfs dentry pointer of the real device directory (not links).
* @dentry_name: Name of the real dentry.
*
@@ -159,6 +162,7 @@ struct device_opp {
unsigned int *supported_hw;
unsigned int supported_hw_count;
const char *prop_name;
+ struct regulator *regulator;

#ifdef CONFIG_DEBUG_FS
struct dentry *dentry;
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 95403d2ccaf5..c70a18ac9c8a 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -60,6 +60,8 @@ int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
void dev_pm_opp_put_supported_hw(struct device *dev);
int dev_pm_opp_set_prop_name(struct device *dev, const char *name);
void dev_pm_opp_put_prop_name(struct device *dev);
+int dev_pm_opp_set_regulator(struct device *dev, const char *name);
+void dev_pm_opp_put_regulator(struct device *dev);
#else
static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
@@ -151,6 +153,13 @@ static inline int dev_pm_opp_set_prop_name(struct device *dev, const char *name)

static inline void dev_pm_opp_put_prop_name(struct device *dev) {}

+static inline int dev_pm_opp_set_regulator(struct device *dev, const char *name)
+{
+ return -EINVAL;
+}
+
+static inline void dev_pm_opp_put_regulator(struct device *dev) {}
+
#endif /* CONFIG_PM_OPP */

#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
--
2.7.1.370.gb2aa7f8
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