The /sys/class/devfreq/.../target_freq shows the next governor
predicted target frequency of the corresponding devfreq object.
-What: /sys/class/devfreq/.../polling_interval
-Date: September 2011
-Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
-Description:
- The /sys/class/devfreq/.../polling_interval shows and sets
- the requested polling interval of the corresponding devfreq
- object. The values are represented in ms. If the value is
- less than 1 jiffy, it is considered to be 0, which means
- no polling. This value is meaningless if the governor is
- not polling; thus. If the governor is not using
- devfreq-provided central polling
- (/sys/class/devfreq/.../central_polling is 0), this value
- may be useless.
-
What: /sys/class/devfreq/.../trans_stat
Date: October 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
as following:
echo 0 > /sys/class/devfreq/.../trans_stat
-What: /sys/class/devfreq/.../userspace/set_freq
-Date: September 2011
-Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
-Description:
- The /sys/class/devfreq/.../userspace/set_freq shows and
- sets the requested frequency for the devfreq object if
- userspace governor is in effect.
-
What: /sys/class/devfreq/.../available_frequencies
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>
The max_freq overrides min_freq because max_freq may be
used to throttle devices to avoid overheating.
+What: /sys/class/devfreq/.../polling_interval
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../polling_interval shows and sets
+ the requested polling interval of the corresponding devfreq
+ object. The values are represented in ms. If the value is
+ less than 1 jiffy, it is considered to be 0, which means
+ no polling. This value is meaningless if the governor is
+ not polling; thus. If the governor is not using
+ devfreq-provided central polling
+ (/sys/class/devfreq/.../central_polling is 0), this value
+ may be useless.
+
+ A list of governors that support the node:
+ - simple_ondmenad
+ - tegra_actmon
+
+What: /sys/class/devfreq/.../userspace/set_freq
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../userspace/set_freq shows and
+ sets the requested frequency for the devfreq object if
+ userspace governor is in effect.
+
+ A list of governors that support the node:
+ - userspace
+
What: /sys/class/devfreq/.../timer
Date: July 2020
Contact: Chanwoo Choi <cw00.choi@samsung.com>
as following:
echo deferrable > /sys/class/devfreq/.../timer
echo delayed > /sys/class/devfreq/.../timer
+
+ A list of governors that support the node:
+ - simple_ondemand
#include <trace/events/devfreq.h>
#define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
+#define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
#define HZ_PER_KHZ 1000
static struct class *devfreq_class;
kfree(devfreq);
}
+static void create_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov);
+static void remove_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov);
+
/**
* devfreq_add_device() - Add devfreq feature to the device
* @dev: the device to add devfreq feature.
__func__);
goto err_init;
}
+ create_sysfs_files(devfreq, devfreq->governor);
list_add(&devfreq->node, &devfreq_list);
if (!devfreq)
return -EINVAL;
- if (devfreq->governor)
+ if (devfreq->governor) {
devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_STOP, NULL);
+ remove_sysfs_files(devfreq, devfreq->governor);
+ }
+
device_unregister(&devfreq->dev);
return 0;
goto out;
}
+ /*
+ * Stop the current governor and remove the specific sysfs files
+ * which depend on current governor.
+ */
ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
if (ret) {
dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
__func__, df->governor->name, ret);
goto out;
}
+ remove_sysfs_files(df, df->governor);
+ /*
+ * Start the new governor and create the specific sysfs files
+ * which depend on the new governor.
+ */
prev_governor = df->governor;
df->governor = governor;
strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
if (ret) {
dev_warn(dev, "%s: Governor %s not started(%d)\n",
__func__, df->governor->name, ret);
+
+ /* Restore previous governor */
df->governor = prev_governor;
strncpy(df->governor_name, prev_governor->name,
DEVFREQ_NAME_LEN);
"%s: reverting to Governor %s failed (%d)\n",
__func__, df->governor_name, ret);
df->governor = NULL;
+ goto out;
}
}
+
+ /*
+ * Create the sysfs files for the new governor. But if failed to start
+ * the new governor, restore the sysfs files of previous governor.
+ */
+ create_sysfs_files(df, df->governor);
+
out:
mutex_unlock(&devfreq_list_lock);
}
static DEVICE_ATTR_RO(target_freq);
-static ssize_t polling_interval_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct devfreq *df = to_devfreq(dev);
-
- if (!df->profile)
- return -EINVAL;
-
- return sprintf(buf, "%d\n", df->profile->polling_ms);
-}
-
-static ssize_t polling_interval_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct devfreq *df = to_devfreq(dev);
- unsigned int value;
- int ret;
-
- if (!df->governor)
- return -EINVAL;
-
- ret = sscanf(buf, "%u", &value);
- if (ret != 1)
- return -EINVAL;
-
- df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
- ret = count;
-
- return ret;
-}
-static DEVICE_ATTR_RW(polling_interval);
-
static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
}
static DEVICE_ATTR_RW(trans_stat);
+static struct attribute *devfreq_attrs[] = {
+ &dev_attr_name.attr,
+ &dev_attr_governor.attr,
+ &dev_attr_available_governors.attr,
+ &dev_attr_cur_freq.attr,
+ &dev_attr_available_frequencies.attr,
+ &dev_attr_target_freq.attr,
+ &dev_attr_min_freq.attr,
+ &dev_attr_max_freq.attr,
+ &dev_attr_trans_stat.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(devfreq);
+
+static ssize_t polling_interval_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+
+ if (!df->profile)
+ return -EINVAL;
+
+ return sprintf(buf, "%d\n", df->profile->polling_ms);
+}
+
+static ssize_t polling_interval_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned int value;
+ int ret;
+
+ if (!df->governor)
+ return -EINVAL;
+
+ ret = sscanf(buf, "%u", &value);
+ if (ret != 1)
+ return -EINVAL;
+
+ df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
+ ret = count;
+
+ return ret;
+}
+static DEVICE_ATTR_RW(polling_interval);
+
static ssize_t timer_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
}
static DEVICE_ATTR_RW(timer);
-static struct attribute *devfreq_attrs[] = {
- &dev_attr_name.attr,
- &dev_attr_governor.attr,
- &dev_attr_available_governors.attr,
- &dev_attr_cur_freq.attr,
- &dev_attr_available_frequencies.attr,
- &dev_attr_target_freq.attr,
- &dev_attr_polling_interval.attr,
- &dev_attr_min_freq.attr,
- &dev_attr_max_freq.attr,
- &dev_attr_trans_stat.attr,
- &dev_attr_timer.attr,
- NULL,
-};
-ATTRIBUTE_GROUPS(devfreq);
+#define CREATE_SYSFS_FILE(df, name) \
+{ \
+ int ret; \
+ ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr); \
+ if (ret < 0) { \
+ dev_warn(&df->dev, \
+ "Unable to create attr(%s)\n", "##name"); \
+ } \
+} \
+
+/* Create the specific sysfs files which depend on each governor. */
+static void create_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov)
+{
+ if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+ CREATE_SYSFS_FILE(devfreq, polling_interval);
+ if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+ CREATE_SYSFS_FILE(devfreq, timer);
+}
+
+/* Remove the specific sysfs files which depend on each governor. */
+static void remove_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov)
+{
+ if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+ sysfs_remove_file(&devfreq->dev.kobj,
+ &dev_attr_polling_interval.attr);
+ if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+ sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
+}
/**
* devfreq_summary_show() - Show the summary of the devfreq devices
mutex_lock(&devfreq->lock);
cur_freq = devfreq->previous_freq;
get_freq_range(devfreq, &min_freq, &max_freq);
- polling_ms = devfreq->profile->polling_ms;
timer = devfreq->profile->timer;
+
+ if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
+ polling_ms = devfreq->profile->polling_ms;
+ else
+ polling_ms = 0;
mutex_unlock(&devfreq->lock);
seq_printf(s,