7 files changed, 803 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 95b9e7eefadc..a1efd75070aa 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -130,4 +130,6 @@ source "drivers/iommu/Kconfig"
 
 source "drivers/virt/Kconfig"
 
+source "drivers/devfreq/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 7fa433a7030c..97c957b50819 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -127,3 +127,5 @@ obj-$(CONFIG_IOMMU_SUPPORT)	+= iommu/
 
 # Virtualization drivers
 obj-$(CONFIG_VIRT_DRIVERS)      += virt/
+
+obj-$(CONFIG_PM_DEVFREQ)        += devfreq/
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
new file mode 100644
index 000000000000..1fb42de4f420
--- /dev/null
+++ b/drivers/devfreq/Kconfig
@@ -0,0 +1,39 @@
+config ARCH_HAS_DEVFREQ
+        bool
+        depends on ARCH_HAS_OPP
+        help
+          Denotes that the architecture supports DEVFREQ. If the architecture
+          supports multiple OPP entries per device and the frequency of the
+          devices with OPPs may be altered dynamically, the architecture
+          supports DEVFREQ.
+
+menuconfig PM_DEVFREQ
+        bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
+        depends on PM_OPP && ARCH_HAS_DEVFREQ
+        help
+          With OPP support, a device may have a list of frequencies and
+          voltages available. DEVFREQ, a generic DVFS framework can be
+          registered for a device with OPP support in order to let the
+          governor provided to DEVFREQ choose an operating frequency
+          based on the OPP's list and the policy given with DEVFREQ.
+
+          Each device may have its own governor and policy. DEVFREQ can
+          reevaluate the device state periodically and/or based on the
+          OPP list changes (each frequency/voltage pair in OPP may be
+          disabled or enabled).
+
+          Like some CPUs with CPUFREQ, a device may have multiple clocks.
+          However, because the clock frequencies of a single device are
+          determined by the single device's state, an instance of DEVFREQ
+          is attached to a single device and returns a "representative"
+          clock frequency from the OPP of the device, which is also attached
+          to a device by 1-to-1. The device registering DEVFREQ takes the
+          responsiblity to "interpret" the frequency listed in OPP and
+          to set its every clock accordingly with the "target" callback
+          given to DEVFREQ.
+
+if PM_DEVFREQ
+
+comment "DEVFREQ Drivers"
+
+endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
new file mode 100644
index 000000000000..168934a12b38
--- /dev/null
+++ b/drivers/devfreq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_PM_DEVFREQ)        += devfreq.o
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
new file mode 100644
index 000000000000..f3100b19f798
--- /dev/null
+++ b/drivers/devfreq/devfreq.c
@@ -0,0 +1,532 @@
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ *          for Non-CPU Devices.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *      MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/opp.h>
+#include <linux/devfreq.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/hrtimer.h>
+#include "governor.h"
+
+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.
+ */
+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 */
+static LIST_HEAD(devfreq_list);
+static DEFINE_MUTEX(devfreq_list_lock);
+
+/**
+ * find_device_devfreq() - find devfreq struct using device pointer
+ * @dev:        device pointer used to lookup device devfreq.
+ *
+ * Search the list of device devfreqs and return the matched device's
+ * devfreq info. devfreq_list_lock should be held by the caller.
+ */
+static struct devfreq *find_device_devfreq(struct device *dev)
+{
+        struct devfreq *tmp_devfreq;
+
+        if (unlikely(IS_ERR_OR_NULL(dev))) {
+                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_devfreq, &devfreq_list, node) {
+                if (tmp_devfreq->dev.parent == dev)
+                        return tmp_devfreq;
+        }
+
+        return ERR_PTR(-ENODEV);
+}
+
+/**
+ * update_devfreq() - Reevaluate the device and configure frequency.
+ * @devfreq:    the devfreq instance.
+ *
+ * Note: Lock devfreq->lock before calling update_devfreq
+ *       This function is exported for governors.
+ */
+int update_devfreq(struct devfreq *devfreq)
+{
+        unsigned long freq;
+        int err = 0;
+
+        if (!mutex_is_locked(&devfreq->lock)) {
+                WARN(true, "devfreq->lock must be locked by the caller.\n");
+                return -EINVAL;
+        }
+
+        /* Reevaluate the proper frequency */
+        err = devfreq->governor->get_target_freq(devfreq, &freq);
+        if (err)
+                return err;
+
+        err = devfreq->profile->target(devfreq->dev.parent, &freq);
+        if (err)
+                return err;
+
+        devfreq->previous_freq = freq;
+        return err;
+}
+
+/**
+ * devfreq_notifier_call() - Notify that the device frequency requirements
+ *                         has been changed out of devfreq framework.
+ * @nb          the notifier_block (supposed to be devfreq->nb)
+ * @type        not used
+ * @devp        not used
+ *
+ * Called by a notifier that uses devfreq->nb.
+ */
+static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
+                                 void *devp)
+{
+        struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
+        int ret;
+
+        mutex_lock(&devfreq->lock);
+        ret = update_devfreq(devfreq);
+        mutex_unlock(&devfreq->lock);
+
+        return ret;
+}
+
+/**
+ * _remove_devfreq() - Remove devfreq from the device.
+ * @devfreq:    the devfreq struct
+ * @skip:       skip calling device_unregister().
+ *
+ * Note that the caller should lock devfreq->lock before calling
+ * this. _remove_devfreq() will unlock it and free devfreq
+ * internally. devfreq_list_lock should be locked by the caller