Merge branch 'pm-devfreq'

* pm-devfreq: (23 commits)
  PM / devfreq: remove compiler error with module governors (2)
  PM / devfreq: Fix return value in devfreq_remove_governor()
  PM / devfreq: Fix incorrect argument in error message
  PM / devfreq: missing rcu_read_lock() added for find_device_opp()
  PM / devfreq: remove compiler error when a governor is module
  PM / devfreq: exynos4_bus.c: Fixed an alignment of the func call args.
  PM / devfreq: Add sysfs node to expose available governors
  PM / devfreq: allow sysfs governor node to switch governor
  PM / devfreq: governors: add GPL module license and allow module build
  PM / devfreq: map devfreq drivers to governor using name
  PM / devfreq: register governors with devfreq framework
  PM / devfreq: provide hooks for governors to be registered
  PM / devfreq: export update_devfreq
  PM / devfreq: Add sysfs node for representing frequency transition information.
  PM / devfreq: Add sysfs node to expose available frequencies
  PM / devfreq: documentation cleanups for devfreq header
  PM / devfreq: Use devm_* functions in exynos4_bus.c
  PM / devfreq: make devfreq_class static
  PM / devfreq: fix sscanf handling for writable sysfs entries
  PM / devfreq: kernel-doc typo corrections
  ...

8 files changed, 835 insertions, 328 deletions

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index f6b0a6e2ea50..0f079be13305 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -30,7 +30,7 @@ if PM_DEVFREQ
 comment "DEVFREQ Governors"
 
 config DEVFREQ_GOV_SIMPLE_ONDEMAND
-        bool "Simple Ondemand"
+        tristate "Simple Ondemand"
         help
           Chooses frequency based on the recent load on the device. Works
           similar as ONDEMAND governor of CPUFREQ does. A device with
@@ -39,7 +39,7 @@ config DEVFREQ_GOV_SIMPLE_ONDEMAND
           values to the governor with data field at devfreq_add_device().
 
 config DEVFREQ_GOV_PERFORMANCE
-        bool "Performance"
+        tristate "Performance"
         help
           Sets the frequency at the maximum available frequency.
           This governor always returns UINT_MAX as frequency so that
@@ -47,7 +47,7 @@ config DEVFREQ_GOV_PERFORMANCE
           at any time.
 
 config DEVFREQ_GOV_POWERSAVE
-        bool "Powersave"
+        tristate "Powersave"
         help
           Sets the frequency at the minimum available frequency.
           This governor always returns 0 as frequency so that
@@ -55,7 +55,7 @@ config DEVFREQ_GOV_POWERSAVE
           at any time.
 
 config DEVFREQ_GOV_USERSPACE
-        bool "Userspace"
+        tristate "Userspace"
         help
           Sets the frequency at the user specified one.
           This governor returns the user configured frequency if there
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 4fa1a22c55ea..53766f39aadd 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -27,21 +27,17 @@
 #include <linux/hrtimer.h>
 #include "governor.h"
 
-struct class *devfreq_class;
+static struct class *devfreq_class;
 
 /*
- * devfreq_work periodically monitors every registered device.
- * The minimum polling interval is one jiffy. The polling interval is
- * determined by the minimum polling period among all polling devfreq
- * devices. The resolution of polling interval is one jiffy.
+ * devfreq core provides delayed work based load monitoring helper
+ * functions. Governors can use these or can implement their own
+ * monitoring mechanism.
  */
-static bool polling;
 static struct workqueue_struct *devfreq_wq;
-static struct delayed_work devfreq_work;
-
-/* wait removing if this is to be removed */
-static struct devfreq *wait_remove_device;
 
+/* The list of all device-devfreq governors */
+static LIST_HEAD(devfreq_governor_list);
 /* The list of all device-devfreq */
 static LIST_HEAD(devfreq_list);
 static DEFINE_MUTEX(devfreq_list_lock);
@@ -73,6 +69,79 @@ static struct devfreq *find_device_devfreq(struct device *dev)
 }
 
 /**
+ * devfreq_get_freq_level() - Lookup freq_table for the frequency
+ * @devfreq:    the devfreq instance
+ * @freq:       the target frequency
+ */
+static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
+{
+        int lev;
+
+        for (lev = 0; lev < devfreq->profile->max_state; lev++)
+                if (freq == devfreq->profile->freq_table[lev])
+                        return lev;
+
+        return -EINVAL;
+}
+
+/**
+ * devfreq_update_status() - Update statistics of devfreq behavior
+ * @devfreq:    the devfreq instance
+ * @freq:       the update target frequency
+ */
+static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+{
+        int lev, prev_lev;
+        unsigned long cur_time;
+
+        lev = devfreq_get_freq_level(devfreq, freq);
+        if (lev < 0)
+                return lev;
+
+        cur_time = jiffies;
+        devfreq->time_in_state[lev] +=
+                         cur_time - devfreq->last_stat_updated;
+        if (freq != devfreq->previous_freq) {
+                prev_lev = devfreq_get_freq_level(devfreq,
+                                                devfreq->previous_freq);
+                devfreq->trans_table[(prev_lev *
+                                devfreq->profile->max_state) + lev]++;
+                devfreq->total_trans++;
+        }
+        devfreq->last_stat_updated = cur_time;
+
+        return 0;
+}
+
+/**
+ * find_devfreq_governor() - find devfreq governor from name
+ * @name:       name of the governor
+ *
+ * Search the list of devfreq governors and return the matched
+ * governor's pointer. devfreq_list_lock should be held by the caller.
+ */
+static struct devfreq_governor *find_devfreq_governor(const char *name)
+{
+        struct devfreq_governor *tmp_governor;
+
+        if (unlikely(IS_ERR_OR_NULL(name))) {
+                pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+                return ERR_PTR(-EINVAL);
+        }
+        WARN(!mutex_is_locked(&devfreq_list_lock),
+             "devfreq_list_lock must be locked.");
+
+        list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
+                if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
+                        return tmp_governor;
+        }
+
+        return ERR_PTR(-ENODEV);
+}
+
+/* Load monitoring helper functions for governors use */
+
+/**
  * update_devfreq() - Reevaluate the device and configure frequency.
  * @devfreq:    the devfreq instance.
  *
@@ -90,6 +159,9 @@ int update_devfreq(struct devfreq *devfreq)
                 return -EINVAL;
         }
 
+        if (!devfreq->governor)
+                return -EINVAL;
+
         /* Reevaluate the proper frequency */
         err = devfreq->governor->get_target_freq(devfreq, &freq);
         if (err)
@@ -116,16 +188,173 @@ int update_devfreq(struct devfreq *devfreq)
         if (err)
                 return err;