This allows us to select governor runtime from the default configuration without having to rebuild kernel or the devfreq driver using the sysfs node: /sys/class/devfreq/.../governor cat of the governor will return valid governor and an echo 'governor_name'>governor will switch governor
Cc: Rajagopal Venkat <[email protected]> Cc: MyungJoo Ham <[email protected]> Cc: Kyungmin Park <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Kevin Hilman <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Nishanth Menon <[email protected]> --- Documentation/ABI/testing/sysfs-class-devfreq | 2 +- drivers/devfreq/devfreq.c | 40 ++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq index e672ccb..293f6b2 100644 --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -11,7 +11,7 @@ What: /sys/class/devfreq/.../governor Date: September 2011 Contact: MyungJoo Ham <[email protected]> Description: - The /sys/class/devfreq/.../governor shows the name of the + The /sys/class/devfreq/.../governor show or set the name of the governor used by the corresponding devfreq object. What: /sys/class/devfreq/.../cur_freq diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index bd96e32..8535f8c 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -629,6 +629,44 @@ static ssize_t show_governor(struct device *dev, return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name); } +static ssize_t store_governor(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + int ret = 0; + struct devfreq_governor *governor; + + mutex_lock(&devfreq_list_lock); + governor = find_devfreq_governor(buf); + if (IS_ERR(governor)) { + ret = PTR_ERR(governor); + goto out; + } + if (df->governor == governor) + goto out; + + if (df->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; + } + } + df->governor = governor; + strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); + ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); + if (ret) + dev_warn(dev, "%s: Governor %s not started(%d)\n", + __func__, df->governor->name, ret); +out: + mutex_unlock(&devfreq_list_lock); + + if (!ret) + ret = count; + return ret; +} + static ssize_t show_freq(struct device *dev, struct device_attribute *attr, char *buf) { @@ -773,7 +811,7 @@ static ssize_t show_available_freqs(struct device *d, } static struct device_attribute devfreq_attrs[] = { - __ATTR(governor, S_IRUGO, show_governor, NULL), + __ATTR(governor, S_IRUGO | S_IWUSR, show_governor, store_governor), __ATTR(cur_freq, S_IRUGO, show_freq, NULL), __ATTR(available_frequencies, S_IRUGO, show_available_freqs, NULL), __ATTR(target_freq, S_IRUGO, show_target_freq, NULL), -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
