1 files changed, 44 insertions, 1 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 0d7be03d561f..ff960f084c11 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -688,6 +688,49 @@ 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;
+        char str_governor[DEVFREQ_NAME_LEN + 1];
+        struct devfreq_governor *governor;
+
+        ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
+        if (ret != 1)
+                return -EINVAL;
+
+        mutex_lock(&devfreq_list_lock);
+        governor = find_devfreq_governor(str_governor);
+        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)
 {
@@ -873,7 +916,7 @@ static ssize_t show_trans_table(struct device *dev, struct device_attribute *att
 }
 
 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),