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PM / OPP: Add OPP availability change notifier. 

The patch enables to register notifier_block for an OPP-device in order
to get notified for any changes in the availability of OPPs of the
device. For example, if a new OPP is inserted or enable/disable status
of an OPP is changed, the notifier is executed.

This enables the usage of opp_add, opp_enable, and opp_disable to
directly take effect with any connected entities such as cpufreq or
devfreq.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mike Turquette <mturquette@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
hifive-unleashed-5.1
MyungJoo Ham 2011-09-30 22:35:12 +02:00 committed by Rafael J. Wysocki
parent a102a9ece5
commit 03ca370fbf
2 changed files with 42 additions and 0 deletions
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30
drivers/base/power/opp.c
View File

@ -73,6 +73,7 @@ struct opp {
* RCU usage: nodes are not modified in the list of device_opp,
* however addition is possible and is secured by dev_opp_list_lock
* @dev: device pointer
* @head: notifier head to notify the OPP availability changes.
* @opp_list: list of opps
*
* This is an internal data structure maintaining the link to opps attached to
@ -83,6 +84,7 @@ struct device_opp {
struct list_head node;
struct device *dev;
struct srcu_notifier_head head;
struct list_head opp_list;
};
@ -404,6 +406,7 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
}
dev_opp->dev = dev;
srcu_init_notifier_head(&dev_opp->head);
INIT_LIST_HEAD(&dev_opp->opp_list);
/* Secure the device list modification */
@ -428,6 +431,11 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
list_add_rcu(&new_opp->node, head);
mutex_unlock(&dev_opp_list_lock);
/*
* Notify the changes in the availability of the operable
* frequency/voltage list.
*/
srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp);
return 0;
}
@ -504,6 +512,14 @@ static int opp_set_availability(struct device *dev, unsigned long freq,
mutex_unlock(&dev_opp_list_lock);
synchronize_rcu();
/* Notify the change of the OPP availability */
if (availability_req)
srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ENABLE,
new_opp);
else
srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE,
new_opp);
/* clean up old opp */
new_opp = opp;
goto out;
@ -643,3 +659,17 @@ void opp_free_cpufreq_table(struct device *dev,
*table = NULL;
}
#endif /* CONFIG_CPU_FREQ */
/**
* opp_get_notifier() - find notifier_head of the device with opp
* @dev: device pointer used to lookup device OPPs.
*/
struct srcu_notifier_head *opp_get_notifier(struct device *dev)
{
struct device_opp *dev_opp = find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_PTR(PTR_ERR(dev_opp)); /* matching type */
return &dev_opp->head;
}

12
include/linux/opp.h
View File

@ -16,9 +16,14 @@
#include <linux/err.h>
#include <linux/cpufreq.h>
#include <linux/notifier.h>
struct opp;
enum opp_event {
OPP_EVENT_ADD, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
};
#if defined(CONFIG_PM_OPP)
unsigned long opp_get_voltage(struct opp *opp);
@ -40,6 +45,8 @@ int opp_enable(struct device *dev, unsigned long freq);
int opp_disable(struct device *dev, unsigned long freq);
struct srcu_notifier_head *opp_get_notifier(struct device *dev);
#else
static inline unsigned long opp_get_voltage(struct opp *opp)
{
@ -89,6 +96,11 @@ static inline int opp_disable(struct device *dev, unsigned long freq)
{
return 0;
}
struct srcu_notifier_head *opp_get_notifier(struct device *dev)
{
return ERR_PTR(-EINVAL);
}
#endif /* CONFIG_PM */
#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP)