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PM / devfreq: provide hooks for governors to be registered

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Add devfreq_add_governor and devfreq_remove_governor which
can be invoked by governors to register with devfreq.

This sets up the stage to dynamically switch governors and
allow governors to be dynamically loaded as well.

Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kevin Hilman <khilman@ti.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
Nishanth Menon 2012-10-29 15:01:43 -05:00 committed by MyungJoo Ham
parent 2df5021fa9
commit 3aa173b8db
3 changed files with 98 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

91
drivers/devfreq/devfreq.c
View file

@ -36,6 +36,8 @@ static struct class *devfreq_class;
*/
static struct workqueue_struct *devfreq_wq;
/* The list of all device-devfreq governors */
static LIST_HEAD(devfreq_governor_list);
/* The list of all device-devfreq */
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
@ -111,6 +113,32 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
return 0;
}
/**
* find_devfreq_governor() - find devfreq governor from name
* @name: name of the governor
*
* Search the list of devfreq governors and return the matched
* governor's pointer. devfreq_list_lock should be held by the caller.
*/
static struct devfreq_governor *find_devfreq_governor(const char *name)
{
struct devfreq_governor *tmp_governor;
if (unlikely(IS_ERR_OR_NULL(name))) {
pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
WARN(!mutex_is_locked(&devfreq_list_lock),
"devfreq_list_lock must be locked.");
list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
return tmp_governor;
}
return ERR_PTR(-ENODEV);
}
/* Load monitoring helper functions for governors use */
/**
@ -515,6 +543,69 @@ int devfreq_resume_device(struct devfreq *devfreq)
}
EXPORT_SYMBOL(devfreq_resume_device);
/**
* devfreq_add_governor() - Add devfreq governor
* @governor: the devfreq governor to be added
*/
int devfreq_add_governor(struct devfreq_governor *governor)
{
struct devfreq_governor *g;
int err = 0;
if (!governor) {
pr_err("%s: Invalid parameters.\n", __func__);
return -EINVAL;
}
mutex_lock(&devfreq_list_lock);
g = find_devfreq_governor(governor->name);
if (!IS_ERR(g)) {
pr_err("%s: governor %s already registered\n", __func__,
g->name);
err = -EINVAL;
goto err_out;
}
list_add(&governor->node, &devfreq_governor_list);
err_out:
mutex_unlock(&devfreq_list_lock);
return err;
}
EXPORT_SYMBOL(devfreq_add_governor);
/**
* devfreq_remove_device() - Remove devfreq feature from a device.
* @governor: the devfreq governor to be removed
*/
int devfreq_remove_governor(struct devfreq_governor *governor)
{
struct devfreq_governor *g;
int err = 0;
if (!governor) {
pr_err("%s: Invalid parameters.\n", __func__);
return -EINVAL;
}
mutex_lock(&devfreq_list_lock);
g = find_devfreq_governor(governor->name);
if (IS_ERR(g)) {
pr_err("%s: governor %s not registered\n", __func__,
g->name);
err = -EINVAL;
goto err_out;
}
list_del(&governor->node);
err_out:
mutex_unlock(&devfreq_list_lock);
return err;
}
EXPORT_SYMBOL(devfreq_remove_governor);
static ssize_t show_governor(struct device *dev,
struct device_attribute *attr, char *buf)
{

4
drivers/devfreq/governor.h
View file

@ -34,4 +34,8 @@ extern void devfreq_monitor_suspend(struct devfreq *devfreq);
extern void devfreq_monitor_resume(struct devfreq *devfreq);
extern void devfreq_interval_update(struct devfreq *devfreq,
unsigned int *delay);
extern int devfreq_add_governor(struct devfreq_governor *governor);
extern int devfreq_remove_governor(struct devfreq_governor *governor);
#endif /* _GOVERNOR_H */

3
include/linux/devfreq.h
View file

@ -92,6 +92,7 @@ struct devfreq_dev_profile {
/**
* struct devfreq_governor - Devfreq policy governor
* @node: list node - contains registered devfreq governors
* @name: Governor's name
* @get_target_freq: Returns desired operating frequency for the device.
* Basically, get_target_freq will run
@ -107,6 +108,8 @@ struct devfreq_dev_profile {
* Note that the callbacks are called with devfreq->lock locked by devfreq.
*/
struct devfreq_governor {
struct list_head node;
const char name[DEVFREQ_NAME_LEN];
int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
int (*event_handler)(struct devfreq *devfreq,