diff options
| -rw-r--r-- | drivers/devfreq/devfreq.c | 31 | ||||
| -rw-r--r-- | drivers/devfreq/governor_passive.c | 1 | ||||
| -rw-r--r-- | include/linux/devfreq.h | 3 |
3 files changed, 31 insertions, 4 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 8e5938c9c7d6..ade279d29f1e 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -940,6 +940,9 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, if (df->governor == governor) { ret = 0; goto out; + } else if (df->governor->immutable || governor->immutable) { + ret = -EINVAL; + goto out; } if (df->governor) { @@ -969,13 +972,33 @@ static ssize_t available_governors_show(struct device *d, struct device_attribute *attr, char *buf) { - struct devfreq_governor *tmp_governor; + struct devfreq *df = to_devfreq(d); ssize_t count = 0; mutex_lock(&devfreq_list_lock); - list_for_each_entry(tmp_governor, &devfreq_governor_list, node) - count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), - "%s ", tmp_governor->name); + + /* + * The devfreq with immutable governor (e.g., passive) shows + * only own governor. + */ + if (df->governor->immutable) { + count = scnprintf(&buf[count], DEVFREQ_NAME_LEN, + "%s ", df->governor_name); + /* + * The devfreq device shows the registered governor except for + * immutable governors such as passive governor . + */ + } else { + struct devfreq_governor *governor; + + list_for_each_entry(governor, &devfreq_governor_list, node) { + if (governor->immutable) + continue; + count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), + "%s ", governor->name); + } + } + mutex_unlock(&devfreq_list_lock); /* Truncate the trailing space */ diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c index 9ef46e2592c4..93795b32dc09 100644 --- a/drivers/devfreq/governor_passive.c +++ b/drivers/devfreq/governor_passive.c @@ -179,6 +179,7 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq, static struct devfreq_governor devfreq_passive = { .name = "passive", + .immutable = 1, .get_target_freq = devfreq_passive_get_target_freq, .event_handler = devfreq_passive_event_handler, }; diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 2de4e2eea180..e0acb0e5243b 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -104,6 +104,8 @@ struct devfreq_dev_profile { * struct devfreq_governor - Devfreq policy governor * @node: list node - contains registered devfreq governors * @name: Governor's name + * @immutable: Immutable flag for governor. If the value is 1, + * this govenror is never changeable to other governor. * @get_target_freq: Returns desired operating frequency for the device. * Basically, get_target_freq will run * devfreq_dev_profile.get_dev_status() to get the @@ -121,6 +123,7 @@ struct devfreq_governor { struct list_head node; const char name[DEVFREQ_NAME_LEN]; + const unsigned int immutable; int (*get_target_freq)(struct devfreq *this, unsigned long *freq); int (*event_handler)(struct devfreq *devfreq, unsigned int event, void *data); |
