Merge tag 'PR_4.7_20160503' of https://git.kernel.org/pub/scm/linux/kernel/git/mzx/devfreq into pm-devfreq

Pull devfreq material for v4.7 from MyungJoo Ham.

"Updates:

- Passive governor: for SoC subsystems that may either
  have an independent voltage rail or have a parent subsystem
  or collegue subsystem sharing a voltage rail, when there
  is a parent of a collegue that is going to be the owner
  of the voltage rail, the dependent subsystem may use the
  passive governor.

- Consolidated exynos bus/mem-if driver: now we have a single
  driver that supports (almost) all Exynos SoC's bus/mem-if subsystems.

- New devfreq drivers included: Exynos NoC probe"

* tag 'PR_4.7_20160503' of https://git.kernel.org/pub/scm/linux/kernel/git/mzx/devfreq:
  PM / devfreq: style/typo fixes
  PM / devfreq: exynos: Add the detailed correlation for Exynos5422 bus
  PM / devfreq: event: Find the instance of devfreq-event device by using phandle
  PM / devfreq: event: Add new Exynos NoC probe driver
  MAINTAINERS: Add samsung bus frequency driver entry
  PM / devfreq: exynos: Remove unused exynos4/5 busfreq driver
  PM / devfreq: exynos: Add the detailed correlation between sub-blocks and power line
  PM / devfreq: exynos: Update documentation for bus devices using passive governor
  PM / devfreq: exynos: Add support of bus frequency of sub-blocks using passive governor
  PM / devfreq: Add new passive governor
  PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier
  PM / devfreq: Add devfreq_get_devfreq_by_phandle()
  PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver
  PM / devfreq: exynos: Add generic exynos bus frequency driver

20 files changed, 1942 insertions, 1824 deletions

diff --git a/Documentation/devicetree/bindings/devfreq/event/exynos-nocp.txt b/Documentation/devicetree/bindings/devfreq/event/exynos-nocp.txt
new file mode 100644
index 000000000000..fd459f00aa5a
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/event/exynos-nocp.txt
@@ -0,0 +1,26 @@
+
+* Samsung Exynos NoC (Network on Chip) Probe device
+
+The Samsung Exynos542x SoC has NoC (Network on Chip) Probe for NoC bus.
+NoC provides the primitive values to get the performance data. The packets
+that the Network on Chip (NoC) probes detects are transported over
+the network infrastructure to observer units. You can configure probes to
+capture packets with header or data on the data request response network,
+or as traffic debug or statistic collectors. Exynos542x bus has multiple
+NoC probes to provide bandwidth information about behavior of the SoC
+that you can use while analyzing system performance.
+
+Required properties:
+- compatible: Should be "samsung,exynos5420-nocp"
+- reg: physical base address of each NoC Probe and length of memory mapped region.
+
+Optional properties:
+- clock-names : the name of clock used by the NoC Probe, "nocp"
+- clocks : phandles for clock specified in "clock-names" property
+
+Example : NoC Probe nodes in Device Tree are listed below.
+
+	nocp_mem0_0: nocp@10CA1000 {
+		compatible = "samsung,exynos5420-nocp";
+		reg = <0x10CA1000 0x200>;
+	};
diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
new file mode 100644
index 000000000000..d3ec8e676b6b
--- /dev/null
+++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
@@ -0,0 +1,409 @@
+* Generic Exynos Bus frequency device
+
+The Samsung Exynos SoC has many buses for data transfer between DRAM
+and sub-blocks in SoC. Most Exynos SoCs share the common architecture
+for buses. Generally, each bus of Exynos SoC includes a source clock
+and a power line, which are able to change the clock frequency
+of the bus in runtime. To monitor the usage of each bus in runtime,
+the driver uses the PPMU (Platform Performance Monitoring Unit), which
+is able to measure the current load of sub-blocks.
+
+The Exynos SoC includes the various sub-blocks which have the each AXI bus.
+The each AXI bus has the owned source clock but, has not the only owned
+power line. The power line might be shared among one more sub-blocks.
+So, we can divide into two type of device as the role of each sub-block.
+There are two type of bus devices as following:
+- parent bus device
+- passive bus device
+
+Basically, parent and passive bus device share the same power line.
+The parent bus device can only change the voltage of shared power line
+and the rest bus devices (passive bus device) depend on the decision of
+the parent bus device. If there are three blocks which share the VDD_xxx
+power line, Only one block should be parent device and then the rest blocks
+should depend on the parent device as passive device.
+
+	VDD_xxx |--- A block (parent)
+		|--- B block (passive)
+		|--- C block (passive)
+
+There are a little different composition among Exynos SoC because each Exynos
+SoC has different sub-blocks. Therefore, such difference should be specified
+in devicetree file instead of each device driver. In result, this driver
+is able to support the bus frequency for all Exynos SoCs.
+
+Required properties for all bus devices:
+- compatible: Should be "samsung,exynos-bus".
+- clock-names : the name of clock used by the bus, "bus".
+- clocks : phandles for clock specified in "clock-names" property.
+- operating-points-v2: the OPP table including frequency/voltage information
+  to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
+
+Required properties only for parent bus device:
+- vdd-supply: the regulator to provide the buses with the voltage.
+- devfreq-events: the devfreq-event device to monitor the current utilization
+  of buses.
+
+Required properties only for passive bus device:
+- devfreq: the parent bus device.
+
+Optional properties only for parent bus device:
+- exynos,saturation-ratio: the percentage value which is used to calibrate
+			the performance count against total cycle count.
+- exynos,voltage-tolerance: the percentage value for bus voltage tolerance
+			which is used to calculate the max voltage.
+
+Detailed correlation between sub-blocks and power line according to Exynos SoC:
+- In case of Exynos3250, there are two power line as following:
+	VDD_MIF |--- DMC
+
+	VDD_INT |--- LEFTBUS (parent device)
+		|--- PERIL
+		|--- MFC
+		|--- G3D
+		|--- RIGHTBUS
+		|--- PERIR
+		|--- FSYS
+		|--- LCD0
+		|--- PERIR
+		|--- ISP
+		|--- CAM
+
+- In case of Exynos4210, there is one power line as following:
+	VDD_INT |--- DMC (parent device)
+		|--- LEFTBUS
+		|--- PERIL
+		|--- MFC(L)
+		|--- G3D
+		|--- TV
+		|--- LCD0
+		|--- RIGHTBUS
+		|--- PERIR
+		|--- MFC(R)
+		|--- CAM
+		|--- FSYS
+		|--- GPS
+		|--- LCD0
+		|--- LCD1
+
+- In case of Exynos4x12, there are two power line as following:
+	VDD_MIF |--- DMC
+
+	VDD_INT |--- LEFTBUS (parent device)
+		|--- PERIL
+		|--- MFC(L)
+		|--- G3D
+		|--- TV
+		|--- IMAGE
+		|--- RIGHTBUS
+		|--- PERIR
+		|--- MFC(R)
+		|--- CAM
+		|--- FSYS
+		|--- GPS
+		|--- LCD0
+		|--- ISP
+
+- In case of Exynos5422, there are two power line as following:
+	VDD_MIF |--- DREX 0 (parent device, DRAM EXpress controller)
+	        |--- DREX 1
+
+	VDD_INT |--- NoC_Core (parent device)
+		|--- G2D
+		|--- G3D
+		|--- DISP1
+		|--- NoC_WCORE
+		|--- GSCL
+		|--- MSCL
+		|--- ISP
+		|--- MFC
+		|--- GEN
+		|--- PERIS
+		|--- PERIC
+		|--- FSYS
+		|--- FSYS2
+
+Example1:
+	Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to
+	power line (regulator). The MIF (Memory Interface) AXI bus is used to
+	transfer data between DRAM and CPU and uses the VDD_MIF regulator.
+
+	- MIF (Memory Interface) block
+	: VDD_MIF |--- DMC (Dynamic Memory Controller)
+
+	- INT (Internal) block
+	: VDD_INT |--- LEFTBUS (parent device)
+		  |--- PERIL
+		  |--- MFC
+		  |--- G3D
+		  |--- RIGHTBUS
+		  |--- FSYS
+		  |--- LCD0
+		  |--- PERIR
+		  |--- ISP
+		  |--- CAM
+
+	- MIF bus's frequency/voltage table
+	-----------------------
+	|Lv| Freq   | Voltage |
+	-----------------------
+	|L1| 50000  |800000   |
+	|L2| 100000 |800000   |
+	|L3| 134000 |800000   |
+	|L4| 200000 |825000   |
+	|L5| 400000 |875000   |
+	-----------------------
+
+	- INT bus's frequency/voltage table
+	----------------------------------------------------------
+	|Block|LEFTBUS|RIGHTBUS|MCUISP |ISP    |PERIL  ||VDD_INT |
+	| name|       |LCD0    |       |       |       ||        |
+	|     |       |FSYS    |       |       |       ||        |
+	|     |       |MFC     |       |       |       ||        |
+	----------------------------------------------------------
+	|Mode |*parent|passive |passive|passive|passive||        |
+	----------------------------------------------------------
+	|Lv   |Frequency                               ||Voltage |
+	----------------------------------------------------------
+	|L1   |50000  |50000   |50000  |50000  |50000  ||900000  |
+	|L2   |80000  |80000   |80000  |80000  |80000  ||900000  |
+	|L3   |100000 |100000  |100000 |100000 |100000 ||1000000 |
+	|L4   |134000 |134000  |200000 |200000 |       ||1000000 |
+	|L5   |200000 |200000  |400000 |300000 |       ||1000000 |
+	----------------------------------------------------------
+
+Example2 :
+	The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
+	is listed below:
+
+	bus_dmc: bus_dmc {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu_dmc CLK_DIV_DMC>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_dmc_opp_table>;
+		status = "disabled";
+	};
+
+	bus_dmc_opp_table: opp_table1 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@50000000 {
+			opp-hz = /bits/ 64 <50000000>;
+			opp-microvolt = <800000>;
+		};
+		opp@100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+			opp-microvolt = <800000>;
+		};
+		opp@134000000 {
+			opp-hz = /bits/ 64 <134000000>;
+			opp-microvolt = <800000>;
+		};
+		opp@200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-microvolt = <825000>;
+		};
+		opp@400000000 {
+			opp-hz = /bits/ 64 <400000000>;
+			opp-microvolt = <875000>;
+		};
+	};
+
+	bus_leftbus: bus_leftbus {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_GDL>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_leftbus_opp_table>;
+		status = "disabled";
+	};
+
+	bus_rightbus: bus_rightbus {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_GDR>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_leftbus_opp_table>;
+		status = "disabled";
+	};
+
+	bus_lcd0: bus_lcd0 {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_ACLK_160>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_leftbus_opp_table>;
+		status = "disabled";
+	};
+
+	bus_fsys: bus_fsys {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_ACLK_200>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_leftbus_opp_table>;
+		status = "disabled";
+	};
+
+	bus_mcuisp: bus_mcuisp {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_ACLK_400_MCUISP>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_mcuisp_opp_table>;
+		status = "disabled";
+	};
+
+	bus_isp: bus_isp {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_ACLK_266>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_isp_opp_table>;
+		status = "disabled";
+	};
+
+	bus_peril: bus_peril {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_DIV_ACLK_100>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_peril_opp_table>;
+		status = "disabled";
+	};
+
+	bus_mfc: bus_mfc {
+		compatible = "samsung,exynos-bus";
+		clocks = <&cmu CLK_SCLK_MFC>;
+		clock-names = "bus";
+		operating-points-v2 = <&bus_leftbus_opp_table>;
+		status = "disabled";
+	};
+
+	bus_leftbus_opp_table: opp_table1 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@50000000 {
+			opp-hz = /bits/ 64 <50000000>;
+			opp-microvolt = <900000>;
+		};
+		opp@80000000 {
+			opp-hz = /bits/ 64 <80000000>;
+			opp-microvolt = <900000>;
+		};
+		opp@100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+			opp-microvolt = <1000000>;
+		};
+		opp@134000000 {
+			opp-hz = /bits/ 64 <134000000>;
+			opp-microvolt = <1000000>;
+		};
+		opp@200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+			opp-microvolt = <1000000>;
+		};
+	};
+
+	bus_mcuisp_opp_table: opp_table2 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@50000000 {
+			opp-hz = /bits/ 64 <50000000>;
+		};
+		opp@80000000 {
+			opp-hz = /bits/ 64 <80000000>;
+		};
+		opp@100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+		};
+		opp@200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+		};
+		opp@400000000 {
+			opp-hz = /bits/ 64 <400000000>;
+		};
+	};
+
+	bus_isp_opp_table: opp_table3 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@50000000 {
+			opp-hz = /bits/ 64 <50000000>;
+		};
+		opp@80000000 {
+			opp-hz = /bits/ 64 <80000000>;
+		};
+		opp@100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+		};
+		opp@200000000 {
+			opp-hz = /bits/ 64 <200000000>;
+		};
+		opp@300000000 {
+			opp-hz = /bits/ 64 <300000000>;
+		};
+	};
+
+	bus_peril_opp_table: opp_table4 {
+		compatible = "operating-points-v2";
+		opp-shared;
+
+		opp@50000000 {
+			opp-hz = /bits/ 64 <50000000>;
+		};
+		opp@80000000 {
+			opp-hz = /bits/ 64 <80000000>;
+		};
+		opp@100000000 {
+			opp-hz = /bits/ 64 <100000000>;
+		};
+	};
+
+
+	Usage case to handle the frequency and voltage of bus on runtime
+	in exynos3250-rinato.dts is listed below:
+
+	&bus_dmc {
+		devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+		vdd-supply = <&buck1_reg>;	/* VDD_MIF */
+		status = "okay";
+	};
+
+	&bus_leftbus {
+		devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+		vdd-supply = <&buck3_reg>;
+		status = "okay";
+	};
+
+	&bus_rightbus {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_lcd0 {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_fsys {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_mcuisp {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_isp {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_peril {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
+
+	&bus_mfc {
+		devfreq = <&bus_leftbus>;
+		status = "okay";
+	};
diff --git a/MAINTAINERS b/MAINTAINERS
index 42e65d128d01..7e9da3aa9851 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3539,6 +3539,15 @@ F:	drivers/devfreq/devfreq-event.c
 F:	include/linux/devfreq-event.h
 F:	Documentation/devicetree/bindings/devfreq/event/
 
+BUS FREQUENCY DRIVER FOR SAMSUNG EXYNOS
+M:	Chanwoo Choi <cw00.choi@samsung.com>
+L:	linux-pm@vger.kernel.org
+L:	linux-samsung-soc@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mzx/devfreq.git
+S:	Maintained
+F:	drivers/devfreq/exynos-bus.c
+F:	Documentation/devicetree/bindings/devfreq/exynos-bus.txt
+
 DEVICE NUMBER REGISTRY
 M:	Torben Mathiasen <device@lanana.org>
 W:	http://lanana.org/docs/device-list/index.html
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 4de78c552251..78dac0e9da11 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -64,30 +64,32 @@ config DEVFREQ_GOV_USERSPACE
 	  Otherwise, the governor does not change the frequency
 	  given at the initialization.
 
+config DEVFREQ_GOV_PASSIVE
+	tristate "Passive"
+	help
+	  Sets the frequency based on the frequency of its parent devfreq
+	  device. This governor does not change the frequency by itself
+	  through sysfs entries. The passive governor recommends that
+	  devfreq device uses the OPP table to get the frequency/voltage.
+
 comment "DEVFREQ Drivers"
 
-config ARM_EXYNOS4_BUS_DEVFREQ
-	bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver"
-	depends on (CPU_EXYNOS4210 || SOC_EXYNOS4212 || SOC_EXYNOS4412) && !ARCH_MULTIPLATFORM
+config ARM_EXYNOS_BUS_DEVFREQ
+	bool "ARM EXYNOS Generic Memory Bus DEVFREQ Driver"
+	depends on ARCH_EXYNOS
 	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select DEVFREQ_GOV_PASSIVE
+	select DEVFREQ_EVENT_EXYNOS_PPMU
+	select PM_DEVFREQ_EVENT
 	select PM_OPP
 	help
-	  This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int)
-	  and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int).
-	  It reads PPMU counters of memory controllers and adjusts
-	  the operating frequencies and voltages with OPP support.
+	  This adds the common DEVFREQ driver for Exynos Memory bus. Exynos
+	  Memory bus has one more group of memory bus (e.g, MIF and INT block).
+	  Each memory bus group could contain many memoby bus block. It reads
+	  PPMU counters of memory controllers by using DEVFREQ-event device
+	  and adjusts the operating frequencies and voltages with OPP support.
 	  This does not yet operate with optimal voltages.
 
-config ARM_EXYNOS5_BUS_DEVFREQ
-	tristate "ARM Exynos5250 Bus DEVFREQ Driver"
-	depends on SOC_EXYNOS5250
-	select DEVFREQ_GOV_SIMPLE_ONDEMAND
-	select PM_OPP
-	help
-	  This adds the DEVFREQ driver for Exynos5250 bus interface (vdd_int).
-	  It reads PPMU counters of memory controllers and adjusts the
-	  operating frequencies and voltages with OPP support.
-
 config ARM_TEGRA_DEVFREQ
        tristate "Tegra DEVFREQ Driver"
        depends on ARCH_TEGRA_124_SOC
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 5134f9ee983d..09f11d9d40d5 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -4,10 +4,10 @@ obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)	+= governor_simpleondemand.o
 obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE)	+= governor_performance.o
 obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
 obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
+obj-$(CONFIG_DEVFREQ_GOV_PASSIVE)	+= governor_passive.o
 
 # DEVFREQ Drivers
-obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/
-obj-$(CONFIG_ARM_EXYNOS5_BUS_DEVFREQ)	+= exynos/
+obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ)	+= exynos-bus.o
 obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra-devfreq.o
 
 # DEVFREQ Event Drivers
diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
index 38bf144ca147..39b048eda2ce 100644
--- a/drivers/devfreq/devfreq-event.c
+++ b/drivers/devfreq/devfreq-event.c
@@ -235,6 +235,11 @@ struct devfreq_event_dev *devfreq_event_get_edev_by_phandle(struct device *dev,
 
 	mutex_lock(&devfreq_event_list_lock);
 	list_for_each_entry(edev, &devfreq_event_list, node) {
+		if (edev->dev.parent && edev->dev.parent->of_node == node)
+			goto out;
+	}
+
+	list_for_each_entry(edev, &devfreq_event_list, node) {
 		if (!strcmp(edev->desc->name, node->name))
 			goto out;
 	}
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 984c5e9e7bdd..1d6c803804d5 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -25,6 +25,7 @@
 #include <linux/list.h>
 #include <linux/printk.h>
 #include <linux/hrtimer.h>
+#include <linux/of.h>
 #include "governor.h"
 
 static struct class *devfreq_class;
@@ -188,6 +189,29 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
 	return ERR_PTR(-ENODEV);
 }
 
+static int devfreq_notify_transition(struct devfreq *devfreq,
+		struct devfreq_freqs *freqs, unsigned int state)
+{
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (state) {
+	case DEVFREQ_PRECHANGE:
+		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+				DEVFREQ_PRECHANGE, freqs);
+		break;
+
+	case DEVFREQ_POSTCHANGE:
+		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+				DEVFREQ_POSTCHANGE, freqs);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /* Load monitoring helper functions for governors use */
 
 /**
@@ -199,7 +223,8 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
  */
 int update_devfreq(struct devfreq *devfreq)
 {
-	unsigned long freq;
+	struct devfreq_freqs freqs;
+	unsigned long freq, cur_freq;
 	int err = 0;
 	u32 flags = 0;
 
@@ -233,10 +258,22 @@ int update_devfreq(struct devfreq *devfreq)
 		flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 	}
 
+	if (devfreq->profile->get_cur_freq)
+		devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
+	else
+		cur_freq = devfreq->previous_freq;
+
+	freqs.old = cur_freq;
+	freqs.new = freq;
+	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
+
 	err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
 	if (err)
 		return err;
 
+	freqs.new = freq;
+	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+
 	if (devfreq->profile->freq_table)
 		if (devfreq_update_status(devfreq, freq))
 			dev_err(&devfreq->dev,
@@ -541,6 +578,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_out;
 	}
 
+	srcu_init_notifier_head(&devfreq->transition_notifier_list);
+
 	mutex_unlock(&devfreq->lock);
 
 	mutex_lock(&devfreq_list_lock);
@@ -639,6 +678,49 @@ struct devfreq *devm_devfreq_add_device(struct device *dev,
 }
 EXPORT_SYMBOL(devm_devfreq_add_device);
 
+#ifdef CONFIG_OF
+/*
+ * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
+ * @dev - instance to the given device
+ * @index - index into list of devfreq
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
+{
+	struct device_node *node;
+	struct devfreq *devfreq;
+
+	if (!dev)
+		return ERR_PTR(-EINVAL);
+
+	if (!dev->of_node)
+		return ERR_PTR(-EINVAL);
+
+	node = of_parse_phandle(dev->of_node, "devfreq", index);
+	if (!node)
+		return ERR_PTR(-ENODEV);
+
+	mutex_lock(&devfreq_list_lock);
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		if (devfreq->dev.parent
+			&& devfreq->dev.parent->of_node == node) {
+			mutex_unlock(&devfreq_list_lock);
+			return devfreq;
+		}
+	}
+	mutex_unlock(&devfreq_list_lock);
+
+	return ERR_PTR(-EPROBE_DEFER);
+}
+#else
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif /* CONFIG_OF */
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
+
 /**
  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
  * @dev:	the device to add devfreq feature.
@@ -1266,6 +1348,129 @@ void devm_devfreq_unregister_opp_notifier(struct device *dev,
 }
 EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
 
+/**
+ * devfreq_register_notifier() - Register a driver with devfreq
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to register.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_register_notifier(struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	int ret = 0;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (list) {
+	case DEVFREQ_TRANSITION_NOTIFIER:
+		ret = srcu_notifier_chain_register(
+				&devfreq->transition_notifier_list, nb);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devfreq_register_notifier);
+
+/*
+ * devfreq_unregister_notifier() - Unregister a driver with devfreq
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_unregister_notifier(struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	int ret = 0;
+
+	if (!devfreq)
+		return -EINVAL;
+
+	switch (list) {
+	case DEVFREQ_TRANSITION_NOTIFIER:
+		ret = srcu_notifier_chain_unregister(
+				&devfreq->transition_notifier_list, nb);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(devfreq_unregister_notifier);
+
+struct devfreq_notifier_devres {
+	struct devfreq *devfreq;
+	struct notifier_block *nb;
+	unsigned int list;
+};
+
+static void devm_devfreq_notifier_release(struct device *dev, void *res)
+{
+	struct devfreq_notifier_devres *this = res;
+
+	devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
+}
+
+/**
+ * devm_devfreq_register_notifier()
+	- Resource-managed devfreq_register_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devm_devfreq_register_notifier(struct device *dev,
+				struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	struct devfreq_notifier_devres *ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
+				GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = devfreq_register_notifier(devfreq, nb, list);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	ptr->devfreq = devfreq;
+	ptr->nb = nb;
+	ptr->list = list;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_notifier);
+
+/**
+ * devm_devfreq_unregister_notifier()
+	- Resource-managed devfreq_unregister_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ * @nb:		The notifier block to be unregistered.
+ * @list:	DEVFREQ_TRANSITION_NOTIFIER.
+ */
+void devm_devfreq_unregister_notifier(struct device *dev,
+				struct devfreq *devfreq,
+				struct notifier_block *nb,
+				unsigned int list)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_notifier);
+
 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 MODULE_DESCRIPTION("devfreq class support");
 MODULE_LICENSE("GPL");
diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
index a11720affc31..1e8b4f469f38 100644
--- a/drivers/devfreq/event/Kconfig
+++ b/drivers/devfreq/event/Kconfig
@@ -13,6 +13,14 @@ menuconfig PM_DEVFREQ_EVENT
 
 if PM_DEVFREQ_EVENT
 
+config DEVFREQ_EVENT_EXYNOS_NOCP
+	bool "EXYNOS NoC (Network On Chip) Probe DEVFREQ event Driver"
+	depends on ARCH_EXYNOS
+	select PM_OPP
+	help
+	  This add the devfreq-event driver for Exynos SoC. It provides NoC
+	  (Network on Chip) Probe counters to measure the bandwidth of AXI bus.
+
 config DEVFREQ_EVENT_EXYNOS_PPMU
 	bool "EXYNOS PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
 	depends on ARCH_EXYNOS
diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
index be146ead79cf..3d6afd352253 100644
--- a/drivers/devfreq/event/Makefile
+++ b/drivers/devfreq/event/Makefile
@@ -1,2 +1,4 @@
 # Exynos DEVFREQ Event Drivers
+
+obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_NOCP) += exynos-nocp.o
 obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_PPMU) += exynos-ppmu.o
diff --git a/drivers/devfreq/event/exynos-nocp.c b/drivers/devfreq/event/exynos-nocp.c
new file mode 100644
index 000000000000..6b6a5f310486
--- /dev/null
+++ b/drivers/devfreq/event/exynos-nocp.c
@@ -0,0 +1,304 @@
+/*
+ * exynos-nocp.c - EXYNOS NoC (Network On Chip) Probe support
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ * Author : Chanwoo Choi <cw00.choi@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/clk.h>
+#include <linux/module.h>
+#include <linux/devfreq-event.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "exynos-nocp.h"
+
+struct exynos_nocp {
+	struct devfreq_event_dev *edev;
+	struct devfreq_event_desc desc;
+
+	struct device *dev;
+
+	struct regmap *regmap;
+	struct clk *clk;
+};
+
+/*
+ * The devfreq-event ops structure for nocp probe.
+ */
+static int exynos_nocp_set_event(struct devfreq_event_dev *edev)
+{
+	struct exynos_nocp *nocp = devfreq_event_get_drvdata(edev);
+	int ret;
+
+	/* Disable NoC