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Commit a88bd2a5 authored by Viresh Kumar's avatar Viresh Kumar
Browse files

PM / OPP: Implement of_dev_pm_opp_find_required_opp() 



A device's DT node or its OPP nodes can contain a phandle to other
device's OPP node, in the "required-opps" property.

This patch implements a routine to find that required OPP from the node
that contains the "required-opps" property.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent fa9b274f

drivers/opp/core.c

+1 −3
Original line number Diff line number Diff line
@@ -33,8 +33,6 @@ LIST_HEAD(opp_tables); 
/* Lock to allow exclusive modification to the device and opp lists */

DEFINE_MUTEX(opp_table_lock);



static void dev_pm_opp_get(struct dev_pm_opp *opp);



static struct opp_device *_find_opp_dev(const struct device *dev,

					struct opp_table *opp_table)

{
@@ -901,7 +899,7 @@ static void _opp_kref_release(struct kref *kref) 
	dev_pm_opp_put_opp_table(opp_table);

}



static void dev_pm_opp_get(struct dev_pm_opp *opp)

void dev_pm_opp_get(struct dev_pm_opp *opp)

{

	kref_get(&opp->kref);

}

drivers/opp/of.c

+54 −0
Original line number Diff line number Diff line
@@ -673,3 +673,57 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, 
	return ret;

}

EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);



/**

 * of_dev_pm_opp_find_required_opp() - Search for required OPP.

 * @dev: The device whose OPP node is referenced by the 'np' DT node.

 * @np: Node that contains the "required-opps" property.

 *

 * Returns the OPP of the device 'dev', whose phandle is present in the "np"

 * node. Although the "required-opps" property supports having multiple

 * phandles, this helper routine only parses the very first phandle in the list.

 *

 * Return: Matching opp, else returns ERR_PTR in case of error and should be

 * handled using IS_ERR.

 *

 * The callers are required to call dev_pm_opp_put() for the returned OPP after

 * use.

 */

struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,

						   struct device_node *np)

{

	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);

	struct device_node *required_np;

	struct opp_table *opp_table;



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table))

		return ERR_CAST(opp_table);



	required_np = of_parse_phandle(np, "required-opps", 0);

	if (unlikely(!required_np)) {

		dev_err(dev, "Unable to parse required-opps\n");

		goto put_opp_table;

	}



	mutex_lock(&opp_table->lock);



	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {

		if (temp_opp->available && temp_opp->np == required_np) {

			opp = temp_opp;



			/* Increment the reference count of OPP */

			dev_pm_opp_get(opp);

			break;

		}

	}



	mutex_unlock(&opp_table->lock);



	of_node_put(required_np);

put_opp_table:

	dev_pm_opp_put_opp_table(opp_table);



	return opp;

}

EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);

drivers/opp/opp.h

+1 −0
Original line number Diff line number Diff line
@@ -187,6 +187,7 @@ struct opp_table { 
};



/* Routines internal to opp core */

void dev_pm_opp_get(struct dev_pm_opp *opp);

void _get_opp_table_kref(struct opp_table *opp_table);

int _get_opp_count(struct opp_table *opp_table);

struct opp_table *_find_opp_table(struct device *dev);

include/linux/pm_opp.h

+6 −0
Original line number Diff line number Diff line
@@ -309,6 +309,7 @@ int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask); 
void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask);

int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);

struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev);

struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev, struct device_node *np);

#else

static inline int dev_pm_opp_of_add_table(struct device *dev)

{
@@ -342,6 +343,11 @@ static inline struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device 
{

	return NULL;

}



static inline struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev, struct device_node *np)

{

	return NULL;

}

#endif



#endif		/* __LINUX_OPP_H__ */