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Subject[PATCH V2 3/3] PM / OPP: Parse 'opp-<prop>-<name>' bindings
Date
OPP bindings (for few properties) allow a platform to choose a
value/range among a set of available options. The options are present as
opp-<prop>-<name>, where the platform needs to supply the <name> string.

The OPP properties which allow such an option are: opp-microvolt and
opp-microamp.

Add support to the OPP-core to parse these bindings, by introducing
dev_pm_opp_{set|put}_prop_name() APIs.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/base/power/opp/core.c | 159 ++++++++++++++++++++++++++++++++++++++----
drivers/base/power/opp/opp.h | 2 +
include/linux/pm_opp.h | 9 +++
3 files changed, 155 insertions(+), 15 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 5449bae74a44..18152e032b19 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -562,6 +562,9 @@ static void _remove_device_opp(struct device_opp *dev_opp)
if (dev_opp->supported_hw)
return;

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

@@ -794,35 +797,48 @@ static int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
}

/* TODO: Support multiple regulators */
-static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev)
+static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
+ struct device_opp *dev_opp)
{
u32 microvolt[3] = {0};
u32 val;
int count, ret;
+ struct property *prop = NULL;
+ char name[NAME_MAX];
+
+ /* Search for "opp-microvolt-<name>" */
+ if (dev_opp->prop_name) {
+ sprintf(name, "opp-microvolt-%s", dev_opp->prop_name);
+ prop = of_find_property(opp->np, name, NULL);
+ }
+
+ if (!prop) {
+ /* Search for "opp-microvolt" */
+ name[13] = '\0';
+ prop = of_find_property(opp->np, name, NULL);

- /* Missing property isn't a problem, but an invalid entry is */
- if (!of_find_property(opp->np, "opp-microvolt", NULL))
- return 0;
+ /* Missing property isn't a problem, but an invalid entry is */
+ if (!prop)
+ return 0;
+ }

- count = of_property_count_u32_elems(opp->np, "opp-microvolt");
+ count = of_property_count_u32_elems(opp->np, name);
if (count < 0) {
- dev_err(dev, "%s: Invalid opp-microvolt property (%d)\n",
- __func__, count);
+ dev_err(dev, "%s: Invalid %s property (%d)\n",
+ __func__, name, count);
return count;
}

/* There can be one or three elements here */
if (count != 1 && count != 3) {
- dev_err(dev, "%s: Invalid number of elements in opp-microvolt property (%d)\n",
- __func__, count);
+ dev_err(dev, "%s: Invalid number of elements in %s property (%d)\n",
+ __func__, name, count);
return -EINVAL;
}

- ret = of_property_read_u32_array(opp->np, "opp-microvolt", microvolt,
- count);
+ ret = of_property_read_u32_array(opp->np, name, microvolt, count);
if (ret) {
- dev_err(dev, "%s: error parsing opp-microvolt: %d\n", __func__,
- ret);
+ dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
return -EINVAL;
}

@@ -830,7 +846,20 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev)
opp->u_volt_min = microvolt[1];
opp->u_volt_max = microvolt[2];

- if (!of_property_read_u32(opp->np, "opp-microamp", &val))
+ /* Search for "opp-microamp-<name>" */
+ prop = NULL;
+ if (dev_opp->prop_name) {
+ sprintf(name, "opp-microamp-%s", dev_opp->prop_name);
+ prop = of_find_property(opp->np, name, NULL);
+ }
+
+ if (!prop) {
+ /* Search for "opp-microamp" */
+ name[12] = '\0';
+ prop = of_find_property(opp->np, name, NULL);
+ }
+
+ if (prop && !of_property_read_u32(opp->np, name, &val))
opp->u_amp = val;

return 0;
@@ -942,6 +971,106 @@ void dev_pm_opp_put_supported_hw(struct device *dev)
}
EXPORT_SYMBOL_GPL(dev_pm_opp_put_supported_hw);

+/**
+ * dev_pm_opp_set_prop_name() - Set prop-extn name
+ * @dev: Device for which the regulator has to be set.
+ * @name: name to postfix to properties.
+ *
+ * This is required only for the V2 bindings, and it enables a platform to
+ * specify the extn to be used for certain property names. The properties to
+ * which the extension will apply are opp-microvolt and opp-microamp. OPP core
+ * should postfix the property name with -<name> while looking for them.
+ *
+ * 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_prop_name(struct device *dev, const char *name)
+{
+ struct device_opp *dev_opp;
+ int ret = 0;
+
+ /* Hold our list modification lock here */
+ mutex_lock(&dev_opp_list_lock);
+
+ dev_opp = _add_device_opp(dev);
+ if (!dev_opp) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ /* Do we already have a prop-name associated with dev_opp? */
+ if (dev_opp->prop_name) {
+ dev_err(dev, "%s: Already have prop-name %s\n", __func__,
+ dev_opp->prop_name);
+ ret = -EBUSY;
+ goto err;
+ }
+
+ dev_opp->prop_name = kstrdup(name, GFP_KERNEL);
+ if (!dev_opp->prop_name) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ 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_prop_name);
+
+/**
+ * dev_pm_opp_put_prop_name() - Releases resources blocked for prop-name
+ * @dev: Device for which the regulator has to be set.
+ *
+ * This is required only for the V2 bindings, and is called for a matching
+ * dev_pm_opp_set_prop_name(). Until this is called, the device_opp structure
+ * will not be freed.
+ *
+ * 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_prop_name(struct device *dev)
+{
+ struct device_opp *dev_opp;
+
+ /* Hold our list modification lock here */
+ 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 (!dev_opp->prop_name) {
+ dev_err(dev, "%s: Doesn't have a prop-name\n", __func__);
+ goto unlock;
+ }
+
+ kfree(dev_opp->prop_name);
+ dev_opp->prop_name = NULL;
+
+ /* 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_prop_name);
+
static bool _opp_is_supported(struct device *dev, struct device_opp *dev_opp,
struct device_node *np)
{
@@ -1036,7 +1165,7 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
if (!of_property_read_u32(np, "clock-latency-ns", &val))
new_opp->clock_latency_ns = val;

- ret = opp_parse_supplies(new_opp, dev);
+ ret = opp_parse_supplies(new_opp, dev, dev_opp);
if (ret)
goto free_opp;

diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 70f4564a6ab9..690638ef36ee 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -131,6 +131,7 @@ struct device_list_opp {
* @suspend_opp: Pointer to OPP to be used during device suspend.
* @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.
* @dentry: debugfs dentry pointer of the real device directory (not links).
* @dentry_name: Name of the real dentry.
*
@@ -157,6 +158,7 @@ struct device_opp {

unsigned int *supported_hw;
unsigned int supported_hw_count;
+ const char *prop_name;

#ifdef CONFIG_DEBUG_FS
struct dentry *dentry;
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 3a85110242f0..95403d2ccaf5 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -58,6 +58,8 @@ struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev);
int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
unsigned int count);
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);
#else
static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
@@ -142,6 +144,13 @@ static inline int dev_pm_opp_set_supported_hw(struct device *dev,

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

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

#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
--
2.6.2.198.g614a2ac


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