Device specific sysfs interface /sys/devices/.../power/devfreq_*
- governor R: name of governor
- cur_freq R: current frequency
- max_freq R: maximum operable frequency
- min_freq R: minimum operable frequency
- polling_interval R: polling interval in ms given with devfreq profile
W: update polling interval.
Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
--
Changed from v7
- removed set_freq from the common devfreq interface
- added get_devfreq, a mutex-protected wrapper for find_device_devfreq
(for sysfs interfaces and later with governor-support)
- corrected ABI documentation.
Changed from v6
- poling_interval is writable.
Changed from v5
- updated devferq_update usage.
Changed from v4
- removed system-wide sysfs interface
- removed tickling sysfs interface
- added set_freq for userspace governor (and any other governors that
require user input)
Changed from v3
- corrected sysfs API usage
- corrected error messages
- moved sysfs entry location
- added sysfs entries
Changed from v2
- add ABI entries for devfreq sysfs interface
---
Documentation/ABI/testing/sysfs-devices-power | 37 ++++++
drivers/devfreq/devfreq.c | 150 +++++++++++++++++++++++++
2 files changed, 187 insertions(+), 0 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power
index 8ffbc25..57f4591 100644
--- a/Documentation/ABI/testing/sysfs-devices-power
+++ b/Documentation/ABI/testing/sysfs-devices-power
@@ -165,3 +165,40 @@ Description:
Not all drivers support this attribute. If it isn't supported,
attempts to read or write it will yield I/O errors.
+
+What: /sys/devices/.../power/devfreq_governor
+Date: July 2011
+Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+Description:
+ The /sys/devices/.../power/devfreq_governor shows the name
+ of the governor used by the corresponding device.
+
+What: /sys/devices/.../power/devfreq_cur_freq
+Date: July 2011
+Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+Description:
+ The /sys/devices/.../power/devfreq_cur_freq shows the current
+ frequency of the corresponding device.
+
+What: /sys/devices/.../power/devfreq_max_freq
+Date: July 2011
+Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+Description:
+ The /sys/devices/.../power/devfreq_max_freq shows the
+ maximum operable frequency of the corresponding device.
+
+What: /sys/devices/.../power/devfreq_min_freq
+Date: July 2011
+Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+Description:
+ The /sys/devices/.../power/devfreq_min_freq shows the
+ minimum operable frequency of the corresponding device.
+
+What: /sys/devices/.../power/devfreq_polling_interval
+Date: July 2011
+Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
+Description:
+ The /sys/devices/.../power/devfreq_polling_interval sets and
+ shows the requested polling interval of the corresponding
+ device. The values are represented in ms. If the value is less
+ than 1 jiffy, it is considered to be 0, which means no polling.
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index df63bdc..5bbece6 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -37,6 +37,8 @@ static struct delayed_work devfreq_work;
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
+static struct attribute_group dev_attr_group;
+
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device devfreq.
@@ -62,6 +64,22 @@ static struct devfreq *find_device_devfreq(struct device *dev)
}
/**
+ * get_devfreq() - find devfreq struct. a wrapped find_device_devfreq()
+ * with mutex protection.
+ * @dev: device pointer used to lookup device devfreq.
+ */
+static struct devfreq *get_devfreq(struct device *dev)
+{
+ struct devfreq *ret;
+
+ mutex_lock(&devfreq_list_lock);
+ ret = find_device_devfreq(dev);
+ mutex_unlock(&devfreq_list_lock);
+
+ return ret;
+}
+
+/**
* devfreq_do() - Check the usage profile of a given device and configure
* frequency and voltage accordingly
* @devfreq: devfreq info of the given device
@@ -149,6 +167,8 @@ static void devfreq_monitor(struct work_struct *work)
dev_err(devfreq->dev, "Due to devfreq_do error(%d), devfreq(%s) is removed from the device\n",
error, devfreq->governor->name);
+ sysfs_unmerge_group(&devfreq->dev->kobj,
+ &dev_attr_group);
list_del(&devfreq->node);
kfree(devfreq);
@@ -239,6 +259,8 @@ int devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile,
queue_delayed_work(devfreq_wq, &devfreq_work,
devfreq->next_polling);
}
+
+ sysfs_merge_group(&dev->kobj, &dev_attr_group);
out:
mutex_unlock(&devfreq_list_lock);
@@ -271,6 +293,8 @@ int devfreq_remove_device(struct device *dev)
goto out;
}
+ sysfs_unmerge_group(&dev->kobj, &dev_attr_group);
+
list_del(&devfreq->node);
srcu_notifier_chain_unregister(nh, &devfreq->nb);
kfree(devfreq);
@@ -279,6 +303,132 @@ out:
return 0;
}
+static ssize_t show_governor(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = get_devfreq(dev);
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+ if (!df->governor)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", df->governor->name);
+}
+
+static ssize_t show_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = get_devfreq(dev);
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+
+ return sprintf(buf, "%lu\n", df->previous_freq);
+}
+
+static ssize_t show_max_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = get_devfreq(dev);
+ unsigned long freq = ULONG_MAX;
+ struct opp *opp;
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+ if (!df->dev)
+ return -EINVAL;
+
+ opp = opp_find_freq_floor(df->dev, &freq);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ return sprintf(buf, "%lu\n", freq);
+}
+
+static ssize_t show_min_freq(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = get_devfreq(dev);
+ unsigned long freq = 0;
+ struct opp *opp;
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+ if (!df->dev)
+ return -EINVAL;
+
+ opp = opp_find_freq_ceil(df->dev, &freq);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ return sprintf(buf, "%lu\n", freq);
+}
+
+static ssize_t show_polling_interval(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = get_devfreq(dev);
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+ if (!df->profile)
+ return -EINVAL;
+
+ return sprintf(buf, "%d\n", df->profile->polling_ms);
+}
+
+static ssize_t store_polling_interval(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = get_devfreq(dev);
+ unsigned int value;
+ int ret;
+
+ if (IS_ERR(df))
+ return PTR_ERR(df);
+ if (!df->profile)
+ return -EINVAL;
+
+ ret = sscanf(buf, "%u", &value);
+ if (ret != 1)
+ return -EINVAL;
+
+ df->profile->polling_ms = value;
+ df->next_polling = df->polling_jiffies
+ = msecs_to_jiffies(value);
+
+ mutex_lock(&devfreq_list_lock);
+ if (df->next_polling > 0 && !polling) {
+ polling = true;
+ queue_delayed_work(devfreq_wq, &devfreq_work,
+ df->next_polling);
+ }
+ mutex_unlock(&devfreq_list_lock);
+
+ return count;
+}
+
+static DEVICE_ATTR(devfreq_governor, 0444, show_governor, NULL);
+static DEVICE_ATTR(devfreq_cur_freq, 0444, show_freq, NULL);
+static DEVICE_ATTR(devfreq_max_freq, 0444, show_max_freq, NULL);
+static DEVICE_ATTR(devfreq_min_freq, 0444, show_min_freq, NULL);
+static DEVICE_ATTR(devfreq_polling_interval, 0644, show_polling_interval,
+ store_polling_interval);
+static struct attribute *dev_entries[] = {
+ &dev_attr_devfreq_governor.attr,
+ &dev_attr_devfreq_cur_freq.attr,
+ &dev_attr_devfreq_max_freq.attr,
+ &dev_attr_devfreq_min_freq.attr,
+ &dev_attr_devfreq_polling_interval.attr,
+ NULL,
+};
+static struct attribute_group dev_attr_group = {
+ .name = power_group_name,
+ .attrs = dev_entries,
+};
+
/**
* devfreq_init() - Initialize data structure for devfreq framework and
* start polling registered devfreq devices.
--
1.7.4.1
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