Merge branch 'pm-devfreq'

* pm-devfreq: (24 commits)
  PM / devfreq: Add debugfs support with devfreq_summary file
  PM / devfreq: exynos: Rename Exynos to lowercase
  PM / devfreq: imx8m-ddrc: Fix inconsistent IS_ERR and PTR_ERR
  PM / devfreq: exynos-bus: Add error log when fail to get devfreq-event
  PM / devfreq: exynos-bus: Disable devfreq-event device when fails
  PM / devfreq: rk3399_dmc: Disable devfreq-event device when fails
  PM / devfreq: imx8m-ddrc: Remove unused defines
  PM / devfreq: exynos-bus: Reduce goto statements and remove unused headers
  PM / devfreq: rk3399_dmc: Add COMPILE_TEST and HAVE_ARM_SMCCC dependency
  PM / devfreq: rockchip-dfi: Convert to devm_platform_ioremap_resource
  PM / devfreq: rk3399_dmc: Add missing of_node_put()
  PM / devfreq: rockchip-dfi: Add missing of_node_put()
  PM / devfreq: Fix multiple kernel-doc warnings
  PM / devfreq: exynos-bus: Extract exynos_bus_profile_init_passive()
  PM / devfreq: exynos-bus: Extract exynos_bus_profile_init()
  PM / devfreq: Move declaration of DEVICE_ATTR_RW(min_freq)
  PM / devfreq: Move statistics to separate struct devfreq_stats
  PM / devfreq: Add clearing transitions stats
  PM / devfreq: Change time stats to 64-bit
  PM / devfreq: Add new name attribute for sysfs
  ...

16 files changed, 856 insertions, 132 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index 01196e19afca..9758eb85ade3 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -7,6 +7,13 @@ Description:
 		The name of devfreq object denoted as ... is same as the
 		name of device using devfreq.
 
+What:		/sys/class/devfreq/.../name
+Date:		November 2019
+Contact:	Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+		The /sys/class/devfreq/.../name shows the name of device
+		of the corresponding devfreq object.
+
 What:		/sys/class/devfreq/.../governor
 Date:		September 2011
 Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>
@@ -48,12 +55,15 @@ What:		/sys/class/devfreq/.../trans_stat
 Date:		October 2012
 Contact:	MyungJoo Ham <myungjoo.ham@samsung.com>
 Description:
-		This ABI shows the statistics of devfreq behavior on a
-		specific device. It shows the time spent in each state and
-		the number of transitions between states.
+		This ABI shows or clears the statistics of devfreq behavior
+		on a specific device. It shows the time spent in each state
+		and the number of transitions between states.
 		In order to activate this ABI, the devfreq target device
 		driver should provide the list of available frequencies
-		with its profile.
+		with its profile. If need to reset the statistics of devfreq
+		behavior on a specific device, enter 0(zero) to 'trans_stat'
+		as following:
+			echo 0 > /sys/class/devfreq/.../trans_stat
 
 What:		/sys/class/devfreq/.../userspace/set_freq
 Date:		September 2011
diff --git a/Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml b/Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml
new file mode 100644
index 000000000000..c9e6c22cb5be
--- /dev/null
+++ b/Documentation/devicetree/bindings/memory-controllers/fsl/imx8m-ddrc.yaml
@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/fsl/imx8m-ddrc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: i.MX8M DDR Controller
+
+maintainers:
+  - Leonard Crestez <leonard.crestez@nxp.com>
+
+description:
+  The DDRC block is integrated in i.MX8M for interfacing with DDR based
+  memories.
+
+  It supports switching between different frequencies at runtime but during
+  this process RAM itself becomes briefly inaccessible so actual frequency
+  switching is implemented by TF-A code which runs from a SRAM area.
+
+  The Linux driver for the DDRC doesn't even map registers (they're included
+  for the sake of "describing hardware"), it mostly just exposes firmware
+  capabilities through standard Linux mechanism like devfreq and OPP tables.
+
+properties:
+  compatible:
+    items:
+      - enum:
+        - fsl,imx8mn-ddrc
+        - fsl,imx8mm-ddrc
+        - fsl,imx8mq-ddrc
+      - const: fsl,imx8m-ddrc
+
+  reg:
+    maxItems: 1
+    description:
+      Base address and size of DDRC CTL area.
+      This is not currently mapped by the imx8m-ddrc driver.
+
+  clocks:
+    maxItems: 4
+
+  clock-names:
+    items:
+      - const: core
+      - const: pll
+      - const: alt
+      - const: apb
+
+  operating-points-v2: true
+  opp-table: true
+
+required:
+  - reg
+  - compatible
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx8mm-clock.h>
+    ddrc: memory-controller@3d400000 {
+        compatible = "fsl,imx8mm-ddrc", "fsl,imx8m-ddrc";
+        reg = <0x3d400000 0x400000>;
+        clock-names = "core", "pll", "alt", "apb";
+        clocks = <&clk IMX8MM_CLK_DRAM_CORE>,
+                 <&clk IMX8MM_DRAM_PLL>,
+                 <&clk IMX8MM_CLK_DRAM_ALT>,
+                 <&clk IMX8MM_CLK_DRAM_APB>;
+        operating-points-v2 = <&ddrc_opp_table>;
+    };
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 35535833b6f7..0b1df12e0f21 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -77,7 +77,7 @@ config DEVFREQ_GOV_PASSIVE
 comment "DEVFREQ Drivers"
 
 config ARM_EXYNOS_BUS_DEVFREQ
-	tristate "ARM EXYNOS Generic Memory Bus DEVFREQ Driver"
+	tristate "ARM Exynos Generic Memory Bus DEVFREQ Driver"
 	depends on ARCH_EXYNOS || COMPILE_TEST
 	select DEVFREQ_GOV_SIMPLE_ONDEMAND
 	select DEVFREQ_GOV_PASSIVE
@@ -91,6 +91,16 @@ config ARM_EXYNOS_BUS_DEVFREQ
 	  and adjusts the operating frequencies and voltages with OPP support.
 	  This does not yet operate with optimal voltages.
 
+config ARM_IMX8M_DDRC_DEVFREQ
+	tristate "i.MX8M DDRC DEVFREQ Driver"
+	depends on (ARCH_MXC && HAVE_ARM_SMCCC) || \
+		(COMPILE_TEST && HAVE_ARM_SMCCC)
+	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select DEVFREQ_GOV_USERSPACE
+	help
+	  This adds the DEVFREQ driver for the i.MX8M DDR Controller. It allows
+	  adjusting DRAM frequency.
+
 config ARM_TEGRA_DEVFREQ
 	tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver"
 	depends on ARCH_TEGRA_3x_SOC || ARCH_TEGRA_114_SOC || \
@@ -115,14 +125,15 @@ config ARM_TEGRA20_DEVFREQ
 
 config ARM_RK3399_DMC_DEVFREQ
 	tristate "ARM RK3399 DMC DEVFREQ Driver"
-	depends on ARCH_ROCKCHIP
+	depends on (ARCH_ROCKCHIP && HAVE_ARM_SMCCC) || \
+		(COMPILE_TEST && HAVE_ARM_SMCCC)
 	select DEVFREQ_EVENT_ROCKCHIP_DFI
 	select DEVFREQ_GOV_SIMPLE_ONDEMAND
 	select PM_DEVFREQ_EVENT
 	help
-          This adds the DEVFREQ driver for the RK3399 DMC(Dynamic Memory Controller).
-          It sets the frequency for the memory controller and reads the usage counts
-          from hardware.
+	  This adds the DEVFREQ driver for the RK3399 DMC(Dynamic Memory Controller).
+	  It sets the frequency for the memory controller and reads the usage counts
+	  from hardware.
 
 source "drivers/devfreq/event/Kconfig"
 
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 338ae8440db6..3eb4d5e6635c 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE)	+= governor_passive.o
 
 # DEVFREQ Drivers
 obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ)	+= exynos-bus.o
+obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ)	+= imx8m-ddrc.o
 obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ)	+= rk3399_dmc.o
 obj-$(CONFIG_ARM_TEGRA_DEVFREQ)		+= tegra30-devfreq.o
 obj-$(CONFIG_ARM_TEGRA20_DEVFREQ)	+= tegra20-devfreq.o
diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
index 3dc5fd6065a3..8c31b0f2e28f 100644
--- a/drivers/devfreq/devfreq-event.c
+++ b/drivers/devfreq/devfreq-event.c
@@ -346,9 +346,9 @@ EXPORT_SYMBOL_GPL(devfreq_event_add_edev);
 
 /**
  * devfreq_event_remove_edev() - Remove the devfreq-event device registered.
- * @dev		: the devfreq-event device
+ * @edev	: the devfreq-event device
  *
- * Note that this function remove the registered devfreq-event device.
+ * Note that this function removes the registered devfreq-event device.
  */
 int devfreq_event_remove_edev(struct devfreq_event_dev *edev)
 {
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 57f6944d65a6..cceee8bc3c2f 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/sched.h>
+#include <linux/debugfs.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -33,6 +34,7 @@
 #define HZ_PER_KHZ	1000
 
 static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
 
 /*
  * devfreq core provides delayed work based load monitoring helper
@@ -209,10 +211,10 @@ static int set_freq_table(struct devfreq *devfreq)
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev, prev_lev, ret = 0;
-	unsigned long cur_time;
+	u64 cur_time;
 
 	lockdep_assert_held(&devfreq->lock);
-	cur_time = jiffies;
+	cur_time = get_jiffies_64();
 
 	/* Immediately exit if previous_freq is not initialized yet. */
 	if (!devfreq->previous_freq)
@@ -224,8 +226,8 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 		goto out;
 	}
 
-	devfreq->time_in_state[prev_lev] +=
-			 cur_time - devfreq->last_stat_updated;
+	devfreq->stats.time_in_state[prev_lev] +=
+			cur_time - devfreq->stats.last_update;
 
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
@@ -234,13 +236,13 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	if (lev != prev_lev) {
-		devfreq->trans_table[(prev_lev *
-				devfreq->profile->max_state) + lev]++;
-		devfreq->total_trans++;
+		devfreq->stats.trans_table[
+			(prev_lev * devfreq->profile->max_state) + lev]++;
+		devfreq->stats.total_trans++;
 	}
 
 out:
-	devfreq->last_stat_updated = cur_time;
+	devfreq->stats.last_update = cur_time;
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -535,7 +537,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
 out_update:
-	devfreq->last_stat_updated = jiffies;
+	devfreq->stats.last_update = get_jiffies_64();
 	devfreq->stop_polling = false;
 
 	if (devfreq->profile->get_cur_freq &&
@@ -807,28 +809,29 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_out;
 	}
 
-	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
+	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 			array3_size(sizeof(unsigned int),
 				    devfreq->profile->max_state,
 				    devfreq->profile->max_state),
 			GFP_KERNEL);
-	if (!devfreq->trans_table) {
+	if (!devfreq->stats.trans_table) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
+	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
-			sizeof(unsigned long),
+			sizeof(*devfreq->stats.time_in_state),
 			GFP_KERNEL);
-	if (!devfreq->time_in_state) {
+	if (!devfreq->stats.time_in_state) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->last_stat_updated = jiffies;
+	devfreq->stats.total_trans = 0;
+	devfreq->stats.last_update = get_jiffies_64();
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1259,6 +1262,14 @@ err_out:
 }
 EXPORT_SYMBOL(devfreq_remove_governor);
 
+static ssize_t name_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct devfreq *devfreq = to_devfreq(dev);
+	return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
+}
+static DEVICE_ATTR_RO(name);
+
 static ssize_t governor_show(struct device *dev,
 			     struct device_attribute *attr, char *buf)
 {
@@ -1461,6 +1472,7 @@ static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
 
 	return sprintf(buf, "%lu\n", min_freq);
 }
+static DEVICE_ATTR_RW(min_freq);
 
 static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 			      const char *buf, size_t count)
@@ -1501,7 +1513,6 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
 
 	return count;
 }
-static DEVICE_ATTR_RW(min_freq);
 
 static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
 			     char *buf)
@@ -1580,18 +1591,47 @@ static ssize_t trans_stat_show(struct device *dev,
 				devfreq->profile->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
-				devfreq->trans_table[(i * max_state) + j]);
-		len += sprintf(buf + len, "%10u\n",
-			jiffies_to_msecs(devfreq->time_in_state[i]));
+				devfreq->stats.trans_table[(i * max_state) + j]);
+
+		len += sprintf(buf + len, "%10llu\n", (u64)
+			jiffies64_to_msecs(devfreq->stats.time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
-					devfreq->total_trans);
+					devfreq->stats.total_trans);
 	return len;
 }
-static DEVICE_ATTR_RO(trans_stat);
+
+static ssize_t trans_stat_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	int err, value;
+
+	if (df->profile->max_state == 0)
+		return count;
+
+	err = kstrtoint(buf, 10, &value);
+	if (err || value != 0)
+		return -EINVAL;
+
+	mutex_lock(&df->lock);
+	memset(df->stats.time_in_state, 0, (df->profile->max_state *
+					sizeof(*df->stats.time_in_state)));
+	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
+					df->profile->max_state,
+					df->profile->max_state));
+	df->stats.total_trans = 0;
+	df->stats.last_update = get_jiffies_64();
+	mutex_unlock(&df->lock);
+
+	return count;
+}
+static DEVICE_ATTR_RW(trans_stat);
 
 static struct attribute *devfreq_attrs[] = {
+	&dev_attr_name.attr,
 	&dev_attr_governor.attr,
 	&dev_attr_available_governors.attr,
 	&dev_attr_cur_freq.attr,
@@ -1605,6 +1645,81 @@ static struct attribute *devfreq_attrs[] = {
 };
 ATTRIBUTE_GROUPS(devfreq);
 
+/**
+ * devfreq_summary_show() - Show the summary of the devfreq devices
+ * @s:		seq_file instance to show the summary of devfreq devices
+ * @data:	not used
+ *
+ * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
+ * It helps that user can know the detailed information of the devfreq devices.
+ *
+ * Return 0 always because it shows the information without any data change.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+	struct devfreq *devfreq;
+	struct devfreq *p_devfreq = NULL;
+	unsigned long cur_freq, min_freq, max_freq;
+	unsigned int polling_ms;
+
+	seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
+			"dev_name",
+			"dev",
+			"parent_dev",
+			"governor",
+			"polling_ms",
+			"cur_freq_Hz",
+			"min_freq_Hz",
+			"max_freq_Hz");
+	seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
+			"------------------------------",
+			"----------",
+			"----------",
+			"---------------",
+			"----------",
+			"------------",
+			"------------",
+			"------------");
+
+	mutex_lock(&devfreq_list_lock);
+
+	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
+		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
+							DEVFREQ_NAME_LEN)) {
+			struct devfreq_passive_data *data = devfreq->data;
+
+			if (data)
+				p_devfreq = data->parent;
+		} else {
+			p_devfreq = NULL;
+		}
+#endif
+
+		mutex_lock(&devfreq->lock);
+		cur_freq = devfreq->previous_freq,
+		get_freq_range(devfreq, &min_freq, &max_freq);
+		polling_ms = devfreq->profile->polling_ms,
+		mutex_unlock(&devfreq->lock);
+
+		seq_printf(s,
+			"%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
+			dev_name(devfreq->dev.parent),
+			dev_name(&devfreq->dev),
+			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
+			devfreq->governor_name,
+			polling_ms,
+			cur_freq,
+			min_freq,
+			max_freq);
+	}
+
+	mutex_unlock(&devfreq_list_lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
 static int __init devfreq_init(void)
 {
 	devfreq_class = class_create(THIS_MODULE, "devfreq");
@@ -1621,6 +1736,11 @@ static int __init devfreq_init(void)
 	}
 	devfreq_class->dev_groups = devfreq_groups;
 
+	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+	debugfs_create_file("devfreq_summary", 0444,
+				devfreq_debugfs, NULL,
+				&devfreq_summary_fops);
+
 	return 0;
 }
 subsys_initcall(devfreq_init);
@@ -1814,7 +1934,7 @@ static void devm_devfreq_notifier_release(struct device *dev, void *res)
 
 /**
  * devm_devfreq_register_notifier()
-	- Resource-managed 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.
@@ -1850,7 +1970,7 @@ EXPORT_SYMBOL(devm_devfreq_register_notifier);
 
 /**
  * devm_devfreq_unregister_notifier()
-	- Resource-managed 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.
diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
index cef2cf5347ca..878825372f6f 100644
--- a/drivers/devfreq/event/Kconfig
+++ b/drivers/devfreq/event/Kconfig
@@ -15,7 +15,7 @@ menuconfig PM_DEVFREQ_EVENT
 if PM_DEVFREQ_EVENT
 
 config DEVFREQ_EVENT_EXYNOS_NOCP
-	tristate "EXYNOS NoC (Network On Chip) Probe DEVFREQ event Driver"
+	tristate "Exynos NoC (Network On Chip) Probe DEVFREQ event Driver"
 	depends on ARCH_EXYNOS || COMPILE_TEST
 	select PM_OPP
 	select REGMAP_MMIO
@@ -24,7 +24,7 @@ config DEVFREQ_EVENT_EXYNOS_NOCP
 	  (Network on Chip) Probe counters to measure the bandwidth of AXI bus.
 
 config DEVFREQ_EVENT_EXYNOS_PPMU
-	tristate "EXYNOS PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
+	tristate "Exynos PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
 	depends on ARCH_EXYNOS || COMPILE_TEST
 	select PM_OPP
 	help
@@ -34,7 +34,7 @@ config DEVFREQ_EVENT_EXYNOS_PPMU
 
 config DEVFREQ_EVENT_ROCKCHIP_DFI
 	tristate "ROCKCHIP DFI DEVFREQ event Driver"
-	depends on ARCH_ROCKCHIP
+	depends on ARCH_ROCKCHIP || COMPILE_TEST
 	help
 	  This add the devfreq-event driver for Rockchip SoC. It provides DFI
 	  (DDR Monitor Module) driver to count ddr load.
diff --git a/drivers/devfreq/event/exynos-nocp.c b/drivers/devfreq/event/exynos-nocp.c
index 1c565926db9f..ccc531ee6938 100644
--- a/drivers/devfreq/event/exynos-nocp.c
+++ b/drivers/devfreq/event/exynos-nocp.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * exynos-nocp.c - EXYNOS NoC (Network On Chip) Probe support
+ * exynos-nocp.c - Exynos NoC (Network On Chip) Probe support
  *
  * Copyright (c) 2016 Samsung Electronics Co., Ltd.
  * Author : Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/drivers/devfreq/event/exynos-nocp.h b/drivers/devfreq/event/exynos-nocp.h
index 55cc96284a36..2d6f08cfd0c5 100644
--- a/drivers/devfreq/event/exynos-nocp.h
+++ b/drivers/devfreq/event/exynos-nocp.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * exynos-nocp.h - EXYNOS NoC (Network on Chip) Probe header file
+ * exynos-nocp.h - Exynos NoC (Network on Chip) Probe header file
  *
  * Copyright (c) 2016 Samsung Electronics Co., Ltd.
  * Author : Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c
index 85c7a77bf3f0..17ed980d9099 100644
--- a/drivers/devfreq/event/exynos-ppmu.c
+++ b/drivers/devfreq/event/exynos-ppmu.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * exynos_ppmu.c - EXYNOS PPMU (Platform Performance Monitoring Unit) support
+ * exynos_ppmu.c - Exynos PPMU (Platform Performance Monitoring Unit) support
  *
  * Copyright (c) 2014-2015 Samsung Electronics Co., Ltd.
  * Author : Chanwoo Choi <cw00.choi@samsung.com>
@@ -101,17 +101,22 @@ static struct __exynos_ppmu_events {
 	PPMU_EVENT(dmc1_1),
 };
 
-static int exynos_ppmu_find_ppmu_id(struct devfreq_event_dev *edev)
+static int __exynos_ppmu_find_ppmu_id(const char *edev_name)
 {
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(ppmu_events); i++)
-		if (!strcmp(edev->desc->name, ppmu_events[i].name))
+		if (!strcmp(edev_name, ppmu_events[i].name))
 			return ppmu_events[i].id;
 
 	return -EINVAL;
 }
 
+static int exynos_ppmu_find_ppmu_id(struct devfreq_event_dev *edev)
+{
+	return __exynos_ppmu_find_ppmu_id(edev->desc->name);
+}
+
 /*
  * The devfreq-event ops structure for PPMU v1.1
  */
@@ -556,13 +561,11 @@ static int of_get_devfreq_events(struct device_node *np,
 			 * use default if not.
 			 */
 			if (info->ppmu_type == EXYNOS_TYPE_PPMU_V2) {
-				struct devfreq_event_dev edev;
 				int id;
 				/* Not all registers take the same value for
 				 * read+write data count.
 				 */
-				edev.desc = &desc[j];
-				id = exynos_ppmu_find_ppmu_id(&edev);
+				id = __exynos_ppmu_find_ppmu_id(desc[j].name);
 
 				switch (id) {
 				case PPMU_PMNCNT0:
diff --git a/drivers/devfreq/event/exynos-ppmu.h b/drivers/devfreq/event/exynos-ppmu.h
index 284420047455..97f667d0cbdd 100644
--- a/drivers/devfreq/event/exynos-ppmu.h
+++ b/drivers/devfreq/event/exynos-ppmu.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * exynos_ppmu.h - EXYNOS PPMU header file
+ * exynos_ppmu.h - Exynos PPMU header file
  *
  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
  * Author : Chanwoo Choi <cw00.choi@samsung.com>
diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
index 5d1042188727..9a88faaf8b27 100644
--- a/drivers/devfreq/event/rockchip-dfi.c
+++ b/drivers/devfreq/event/rockchip-dfi.c
@@ -177,7 +177,6 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rockchip_dfi *data;
-	struct resource *res;
 	struct devfreq_event_desc *desc;
 	struct device_node *np = pdev->dev.of_node, *node;
 
@@ -185,8 +184,7 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
 	if (!data)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	data->regs = devm_ioremap_resource(&pdev->dev, res);
+	data->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(data->regs))
 		return PTR_ERR(data->regs);
 
@@ -200,6 +198,7 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
 	node = of_parse_phandle(np, "rockchip,pmu", 0);
 	if (node) {
 		data->regmap_pmu = syscon_node_to_regmap(node);
+		of_node_put(node);
 		if (IS_ERR(data->regmap_pmu))
 			return PTR_ERR(data->regmap_pmu);
 	}
diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
index c832673273a2..8fa8eb541373 100644
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -15,11 +15,10 @@
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/module.h>
-#include <linux/of_device.h>
+#include <linux/of.h>
 #include <linux/pm_opp.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
-#include <linux/slab.h>
 
 #define DEFAULT_SATURATION_RATIO	40
 
@@ -127,6 +126,7 @@ static int exynos_bus_get_dev_status(struct device *dev,
 
 	ret = exynos_bus_get_event(bus, &edata);
 	if (ret < 0) {
+		dev_err(dev, "failed to get event from devfreq-event devices\n");
 		stat->total_time = stat->busy_time = 0;
 		goto err;
 	}
@@ -287,52 +287,12 @@ err_clk:
 	return ret;
 }
 
-static int exynos_bus_probe(struct platform_device *pdev)
+static int exynos_bus_profile_init(struct exynos_bus *bus,
+				   struct devfreq_dev_profile *profile)
 {
-	struct device *dev = &pdev->dev;
-	struct device_node *np = dev->of_node, *node;
-	struct devfreq_dev_profile *profile;
+	struct device *dev = bus->dev;
 	struct devfreq_simple_ondemand_data *ondemand_data;
-	struct devfreq_passive_data *passive_data;
-	struct devfreq *parent_devfreq;
-	struct exynos_bus *bus;
-	int ret, max_state;
-	unsigned long min_freq, max_freq;
-	bool passive = false;
-
-	if (!np) {
-		dev_err(dev, "failed to find devicetree node\n");
-		return -EINVAL;
-	}
-
-	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
-	if (!bus)
-		return -ENOMEM;
-	mutex_init(&bus->lock);
-	bus->dev = &pdev->dev;
-	platform_set_drvdata(pdev, bus);
-
-	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
-	if (!profile)
-		return -ENOMEM;
-
-	node = of_parse_phandle(dev->of_node, "devfreq", 0);
-	if (node) {
-		of_node_put(node);
-		passive = true;
-	} else {
-		ret = exynos_bus_parent_parse_of(np, bus);
-		if (ret < 0)
-			return ret;
-	}
-
-	/* Parse the device-tree to get the resource information */
-	ret = exynos_bus_parse_of(np, bus);
-	if (ret < 0)
-		goto err_reg;
-
-	if (passive)
-		goto passive;
+	int ret;
 
 	/* Initialize the struct profile and governor data for parent device */
 	profile->polling_ms = 50;
@@ -341,10 +301,9 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	profile->exit = exynos_bus_exit;
 
 	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
-	if (!ondemand_data) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	if (!ondemand_data)
+		return -ENOMEM;
+
 	ondemand_data->upthreshold = 40;
 	ondemand_data->downdifferential = 5;
 
@@ -354,15 +313,14 @@ static int exynos_bus_probe(struct platform_device *pdev)
 						ondemand_data);
 	if (IS_ERR(bus->devfreq)) {
 		dev_err(dev, "failed to add devfreq device\n");
-		ret = PTR_ERR(bus->devfreq);
-		goto err;
+		return PTR_ERR(bus->devfreq);
 	}
 
 	/* Register opp_notifier to catch the change of OPP  */
 	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
 	if (ret < 0) {
 		dev_err(dev, "failed to register opp notifier\n");
-		goto err;
+		return ret;
 	}
 
 	/*
@@ -372,33 +330,44 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	ret = exynos_bus_enable_edev(bus);
 	if (ret < 0) {
 		dev_err(dev, "failed to enable devfreq-event devices\n");
-		goto err;
+		return ret;
 	}
 
 	ret = exynos_bus_set_event(bus);
 	if (ret < 0) {
 		dev_err(dev, "failed to set event to devfreq-event devices\n");
-		goto err;
+		goto err_edev;
 	}
 
-	goto out;
-passive:
+	return 0;
+
+err_edev:
+	if (exynos_bus_disable_edev(bus))
+		dev_warn(dev, "failed to disable the devfreq-event devices\n");
+
+	return ret;
+}
+
+static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
+					   struct devfreq_dev_profile *profile)
+{
+	struct device *dev = bus->dev;
+	struct devfreq_passive_data *passive_data;
+	struct devfreq *parent_devfreq;
+
 	/* Initialize the struct profile and governor data for passive device */
 	profile->target = exynos_bus_target;
 	profile->exit = exynos_bus_passive_exit;
 
 	/* Get the instance of parent devfreq device */
 	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
-	if (IS_ERR(parent_devfreq)) {
-		ret = -EPROBE_DEFER;
-		goto err;
-	}
+	if (IS_ERR(parent_devfreq))
+		return -EPROBE_DEFER;
 
 	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
-	if (!passive_data) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	if (!passive_data)
+		return -ENOMEM;
+
 	passive_data->parent = parent_devfreq;
 
 	/* Add devfreq device for exynos bus with passive governor */
@@ -407,11 +376,61 @@ passive:
 	if (IS_ERR(bus->devfreq)) {
 		dev_err(dev,
 			"failed to add devfreq dev with passive governor\n");
-		ret = PTR_ERR(bus->devfreq);
-		goto err;
+		return PTR_ERR(bus->devfreq);
+	}
+
+	return 0;
+}
+
+static int exynos_bus_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node, *node;
+	struct devfreq_dev_profile *profile;
+	struct exynos_bus *bus;
+	int ret, max_state;
+	unsigned long min_freq, max_freq;
+	bool passive = false;
+
+	if (!np) {
+		dev_err(dev, "failed to find devicetree node\n");
+		return -EINVAL;
 	}
 
-out:
+	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return -ENOMEM;
+	mutex_init(&bus->lock);
+	bus->dev = &pdev->dev;
+	platform_set_drvdata(pdev, bus);
+
+	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
+	if (!profile)
+		return -ENOMEM;
+
+	node = of_parse_phandle(dev->of_node, "devfreq", 0);
+	if (node) {
+		of_node_put(node);
+		passive = true;
+	} else {
+		ret = exynos_bus_parent_parse_of(np, bus);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Parse the device-tree to get the resource information */
+	ret = exynos_bus_parse_of(np, bus);
+	if (ret < 0)
+		goto err_reg;
+
+	if (passive)
+		ret = exynos_bus_profile_init_passive(bus, profile);
+	else
+		ret = exynos_bus_profile_init(bus, profile);
+
+	if (ret < 0)
+		goto err;
+
 	max_state = bus->devfreq->profile->max_state;
 	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
 	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
diff --git a/drivers/devfreq/imx8m-ddrc.c b/drivers/devfreq/imx8m-ddrc.c
new file mode 100644
index 000000000000..bc82d3653bff
--- /dev/null
+++ b/drivers/devfreq/imx8m-ddrc.c
@@ -0,0 +1,471 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/devfreq.h>
+#include <linux/pm_opp.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/arm-smccc.h>
+
+#define IMX_SIP_DDR_DVFS			0xc2000004
+
+/* Query available frequencies. */
+#define IMX_SIP_DDR_DVFS_GET_FREQ_COUNT		0x10
+#define IMX_SIP_DDR_DVFS_GET_FREQ_INFO		0x11
+
+/*
+ * This should be in a 1:1 mapping with devicetree OPPs but
+ * firmware provides additional info.
+ */
+struct imx8m_ddrc_freq {
+	unsigned long rate;
+	unsigned long smcarg;
+	int dram_core_parent_index;
+	int dram_alt_parent_index;
+	int dram_apb_parent_index;
+};
+
+/* Hardware limitation */
+#define IMX8M_DDRC_MAX_FREQ_COUNT 4
+
+/*
+ * i.MX8M DRAM Controller clocks have the following structure (abridged):
+ *
+ * +----------+       |\            +------+
+ * | dram_pll |-------|M| dram_core |      |
+ * +----------+       |U|---------->| D    |
+ *                 /--|X|           |  D   |
+ *   dram_alt_root |  |/            |   R  |
+ *                 |                |    C |
+ *            +---------+           |      |
+ *            |FIX DIV/4|           |      |
+ *            +---------+           |      |
+ *  composite:     |                |      |
+ * +----------+    |                |      |
+ * | dram_alt |----/                |      |
+ * +----------+                     |      |
+ * | dram_apb |-------------------->|      |
+ * +----------+                     +------+
+ *
+ * The dram_pll is used for higher rates and dram_alt is used for lower rates.
+ *
+ * Frequency switching is implemented in TF-A (via SMC call) and can change the
+ * configuration of the clocks, including mux parents. The dram_alt and
+ * dram_apb clocks are "imx composite" and their parent can change too.
+ *
+ * We need to prepare/enable the new mux parents head of switching and update
+ * their information afterwards.
+ */
+struct imx8m_ddrc {
+	struct devfreq_dev_profile profile;
+	struct devfreq *devfreq;
+
+	/* For frequency switching: */
+	struct clk *dram_core;
+	struct clk *dram_pll;
+	struct clk *dram_alt;
+	struct clk *dram_apb;
+
+	int freq_count;
+	struct imx8m_ddrc_freq freq_table[IMX8M_DDRC_MAX_FREQ_COUNT];
+};
+
+static struct imx8m_ddrc_freq *imx8m_ddrc_find_freq(struct imx8m_ddrc *priv,
+						    unsigned long rate)
+{
+	struct imx8m_ddrc_freq *freq;
+	int i;
+
+	/*
+	 * Firmware reports values in MT/s, so we round-down from Hz
+	 * Rounding is extra generous to ensure a match.
+	 */
+	rate = DIV_ROUND_CLOSEST(rate, 250000);
+	for (i = 0; i < priv->freq_count; ++i) {
+		freq = &priv->freq_table[i];
+		if (freq->rate == rate ||
+				freq->rate + 1 == rate ||
+				freq->rate - 1 == rate)
+			return freq;
+	}
+
+	return NULL;
+}
+
+static void imx8m_ddrc_smc_set_freq(int target_freq)
+{
+	struct arm_smccc_res res;
+	u32 online_cpus = 0;
+	int cpu;
+
+	local_irq_disable();
+
+	for_each_online_cpu(cpu)
+		online_cpus |= (1 << (cpu * 8));
+
+	/* change the ddr freqency */
+	arm_smccc_smc(IMX_SIP_DDR_DVFS, target_freq, online_cpus,
+			0, 0, 0, 0, 0, &res);
+
+	local_irq_enable();
+}
+
+static struct clk *clk_get_parent_by_index(struct clk *clk, int index)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_get_parent_by_index(__clk_get_hw(clk), index);
+
+	return hw ? hw->clk : NULL;
+}
+
+static int imx8m_ddrc_set_freq(struct device *dev, struct imx8m_ddrc_freq *freq)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct clk *new_dram_core_parent;
+	struct clk *new_dram_alt_parent;
+	struct clk *new_dram_apb_parent;
+	int ret;
+
+	/*
+	 * Fetch new parents
+	 *
+	 * new_dram_alt_parent and new_dram_apb_parent are optional but
+	 * new_dram_core_parent is not.
+	 */
+	new_dram_core_parent = clk_get_parent_by_index(
+			priv->dram_core, freq->dram_core_parent_index - 1);
+	if (!new_dram_core_parent) {
+		dev_err(dev, "failed to fetch new dram_core parent\n");
+		return -EINVAL;
+	}
+	if (freq->dram_alt_parent_index) {
+		new_dram_alt_parent = clk_get_parent_by_index(
+				priv->dram_alt,
+				freq->dram_alt_parent_index - 1);
+		if (!new_dram_alt_parent) {
+			dev_err(dev, "failed to fetch new dram_alt parent\n");
+			return -EINVAL;
+		}
+	} else
+		new_dram_alt_parent = NULL;
+
+	if (freq->dram_apb_parent_index) {
+		new_dram_apb_parent = clk_get_parent_by_index(
+				priv->dram_apb,
+				freq->dram_apb_parent_index - 1);
+		if (!new_dram_apb_parent) {
+			dev_err(dev, "failed to fetch new dram_apb parent\n");
+			return -EINVAL;
+		}
+	} else
+		new_dram_apb_parent = NULL;
+
+	/* increase reference counts and ensure clks are ON before switch */
+	ret = clk_prepare_enable(new_dram_core_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_core parent: %d\n",
+			ret);
+		goto out;
+	}
+	ret = clk_prepare_enable(new_dram_alt_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_alt parent: %d\n",
+			ret);
+		goto out_disable_core_parent;
+	}
+	ret = clk_prepare_enable(new_dram_apb_parent);
+	if (ret) {
+		dev_err(dev, "failed to enable new dram_apb parent: %d\n",
+			ret);
+		goto out_disable_alt_parent;
+	}
+
+	imx8m_ddrc_smc_set_freq(freq->smcarg);
+
+	/* update parents in clk tree after switch. */
+	ret = clk_set_parent(priv->dram_core, new_dram_core_parent);
+	if (ret)
+		dev_warn(dev, "failed to set dram_core parent: %d\n", ret);
+	if (new_dram_alt_parent) {
+		ret = clk_set_parent(priv->dram_alt, new_dram_alt_parent);
+		if (ret)
+			dev_warn(dev, "failed to set dram_alt parent: %d\n",
+				 ret);
+	}
+	if (new_dram_apb_parent) {
+		ret = clk_set_parent(priv->dram_apb, new_dram_apb_parent);
+		if (ret)
+			dev_warn(dev, "failed to set dram_apb parent: %d\n",
+				 ret);
+	}
+
+	/*
+	 * Explicitly refresh dram PLL rate.
+	 *
+	 * Even if it's marked with CLK_GET_RATE_NOCACHE the rate will not be
+	 * automatically refreshed when clk_get_rate is called on children.
+	 */
+	clk_get_rate(priv->dram_pll);
+
+	/*
+	 * clk_set_parent transfer the reference count from old parent.
+	 * now we drop extra reference counts used during the switch
+	 */
+	clk_disable_unprepare(new_dram_apb_parent);
+out_disable_alt_parent:
+	clk_disable_unprepare(new_dram_alt_parent);
+out_disable_core_parent:
+	clk_disable_unprepare(new_dram_core_parent);
+out:
+	return ret;
+}
+
+static int imx8m_ddrc_target(struct device *dev, unsigned long *freq, u32 flags)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct imx8m_ddrc_freq *freq_info;
+	struct dev_pm_opp *new_opp;
+	unsigned long old_freq, new_freq;
+	int ret;
+
+	new_opp = devfreq_recommended_opp(dev, freq, flags);
+	if (IS_ERR(new_opp)) {
+		ret = PTR_ERR(new_opp);
+		dev_err(dev, "failed to get recommended opp: %d\n", ret);
+		return ret;
+	}
+	dev_pm_opp_put(new_opp);
+
+	old_freq = clk_get_rate(priv->dram_core);
+	if (*freq == old_freq)
+		return 0;
+
+	freq_info = imx8m_ddrc_find_freq(priv, *freq);
+	if (!freq_info)
+		return -EINVAL;
+
+	/*
+	 * Read back the clk rate to verify switch was correct and so that
+	 * we can report it on all error paths.
+	 */
+	ret = imx8m_ddrc_set_freq(dev, freq_info);
+
+	new_freq = clk_get_rate(priv->dram_core);
+	if (ret)
+		dev_err(dev, "ddrc failed freq switch to %lu from %lu: error %d. now at %lu\n",
+			*freq, old_freq, ret, new_freq);
+	else if (*freq != new_freq)
+		dev_err(dev, "ddrc failed freq update to %lu from %lu, now at %lu\n",
+			*freq, old_freq, new_freq);
+	else
+		dev_dbg(dev, "ddrc freq set to %lu (was %lu)\n",
+			*freq, old_freq);
+
+	return ret;
+}
+
+static int imx8m_ddrc_get_cur_freq(struct device *dev, unsigned long *freq)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+
+	*freq = clk_get_rate(priv->dram_core);
+
+	return 0;
+}
+
+static int imx8m_ddrc_get_dev_status(struct device *dev,
+				     struct devfreq_dev_status *stat)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+
+	stat->busy_time = 0;
+	stat->total_time = 0;
+	stat->current_frequency = clk_get_rate(priv->dram_core);
+
+	return 0;
+}
+
+static int imx8m_ddrc_init_freq_info(struct device *dev)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct arm_smccc_res res;
+	int index;
+
+	/* An error here means DDR DVFS API not supported by firmware */
+	arm_smccc_smc(IMX_SIP_DDR_DVFS, IMX_SIP_DDR_DVFS_GET_FREQ_COUNT,
+			0, 0, 0, 0, 0, 0, &res);
+	priv->freq_count = res.a0;
+	if (priv->freq_count <= 0 ||
+			priv->freq_count > IMX8M_DDRC_MAX_FREQ_COUNT)
+		return -ENODEV;
+
+	for (index = 0; index < priv->freq_count; ++index) {
+		struct imx8m_ddrc_freq *freq = &priv->freq_table[index];
+
+		arm_smccc_smc(IMX_SIP_DDR_DVFS, IMX_SIP_DDR_DVFS_GET_FREQ_INFO,
+			      index, 0, 0, 0, 0, 0, &res);
+		/* Result should be strictly positive */
+		if ((long)res.a0 <= 0)
+			return -ENODEV;
+
+		freq->rate = res.a0;
+		freq->smcarg = index;
+		freq->dram_core_parent_index = res.a1;
+		freq->dram_alt_parent_index = res.a2;
+		freq->dram_apb_parent_index = res.a3;
+
+		/* dram_core has 2 options: dram_pll or dram_alt_root */
+		if (freq->dram_core_parent_index != 1 &&
+				freq->dram_core_parent_index != 2)
+			return -ENODEV;
+		/* dram_apb and dram_alt have exactly 8 possible parents */
+		if (freq->dram_alt_parent_index > 8 ||
+				freq->dram_apb_parent_index > 8)
+			return -ENODEV;
+		/* dram_core from alt requires explicit dram_alt parent */
+		if (freq->dram_core_parent_index == 2 &&
+				freq->dram_alt_parent_index == 0)
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int imx8m_ddrc_check_opps(struct device *dev)
+{
+	struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+	struct imx8m_ddrc_freq *freq_info;
+	struct dev_pm_opp *opp;
+	unsigned long freq;
+	int i, opp_count;
+
+	/* Enumerate DT OPPs and disable those not supported by firmware */
+	opp_count = dev_pm_opp_get_opp_count(dev);
+	if (opp_count < 0)
+		return opp_count;
+	for (i = 0, freq = 0; i < opp_count; ++i, ++freq) {
+		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+		if (IS_ERR(opp)) {
+			dev_err(dev, "Failed enumerating OPPs: %ld\n",
+				PTR_ERR(opp));
+			return PTR_ERR(opp);
+		}
+		dev_pm_opp_put(opp);
+
+		freq_info = imx8m_ddrc_find_freq(priv, freq);
+		if (!freq_info) {
+			dev_info(dev, "Disable unsupported OPP %luHz %luMT/s\n",
+					freq, DIV_ROUND_CLOSEST(freq, 250000));
+			dev_pm_opp_disable(dev, freq);
+		}
+	}
+
+	return 0;
+}
+
+static void imx8m_ddrc_exit(struct device *dev)
+{
+	dev_pm_opp_of_remove_table(dev);
+}
+
+static int imx8m_ddrc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx8m_ddrc *priv;
+	const char *gov = DEVFREQ_GOV_USERSPACE;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = imx8m_ddrc_init_freq_info(dev);
+	if (ret) {
+		dev_err(dev, "failed to init firmware freq info: %d\n", ret);
+		return ret;
+	}
+
+	priv->dram_core = devm_clk_get(dev, "core");
+	if (IS_ERR(priv->dram_core)) {
+		ret = PTR_ERR(priv->dram_core);
+		dev_err(dev, "failed to fetch core clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_pll = devm_clk_get(dev, "pll");
+	if (IS_ERR(priv->dram_pll)) {
+		ret = PTR_ERR(priv->dram_pll);
+		dev_err(dev, "failed to fetch pll clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_alt = devm_clk_get(dev, "alt");
+	if (IS_ERR(priv->dram_alt)) {
+		ret = PTR_ERR(priv->dram_alt);
+		dev_err(dev, "failed to fetch alt clock: %d\n", ret);
+		return ret;
+	}
+	priv->dram_apb = devm_clk_get(dev, "apb");
+	if (IS_ERR(priv->dram_apb)) {
+		ret = PTR_ERR(priv->dram_apb);
+		dev_err(dev, "failed to fetch apb clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = dev_pm_opp_of_add_table(dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to get OPP table\n");
+		return ret;
+	}
+
+	ret = imx8m_ddrc_check_opps(dev);
+	if (ret < 0)
+		goto err;
+
+	priv->profile.polling_ms = 1000;
+	priv->profile.target = imx8m_ddrc_target;
+	priv->profile.get_dev_status = imx8m_ddrc_get_dev_status;
+	priv->profile.exit = imx8m_ddrc_exit;
+	priv->profile.get_cur_freq = imx8m_ddrc_get_cur_freq;
+	priv->profile.initial_freq = clk_get_rate(priv->dram_core);
+
+	priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
+						gov, NULL);
+	if (IS_ERR(priv->devfreq)) {
+		ret = PTR_ERR(priv->devfreq);
+		dev_err(dev, "failed to add devfreq device: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	dev_pm_opp_of_remove_table(dev);
+	return ret;
+}
+
+static const struct of_device_id imx8m_ddrc_of_match[] = {
+	{ .compatible = "fsl,imx8m-ddrc", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, imx8m_ddrc_of_match);
+
+static struct platform_driver imx8m_ddrc_platdrv = {
+	.probe		= imx8m_ddrc_probe,
+	.driver = {
+		.name	= "imx8m-ddrc-devfreq",
+		.of_match_table = of_match_ptr(imx8m_ddrc_of_match),
+	},
+};
+module_platform_driver(imx8m_ddrc_platdrv);
+
+MODULE_DESCRIPTION("i.MX8M DDR Controller frequency driver");
+MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
index 2e65d7279d79..24f04f78285b 100644
--- a/drivers/devfreq/rk3399_dmc.c
+++ b/drivers/devfreq/rk3399_dmc.c
@@ -364,7 +364,8 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 			if (res.a0) {
 				dev_err(dev, "Failed to set dram param: %ld\n",
 					res.a0);
-				return -EINVAL;
+				ret = -EINVAL;
+				goto err_edev;
 			}
 		}
 	}
@@ -372,8 +373,11 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 	node = of_parse_phandle(np, "rockchip,pmu", 0);
 	if (node) {
 		data->regmap_pmu = syscon_node_to_regmap(node);
-		if (IS_ERR(data->regmap_pmu))
-			return PTR_ERR(data->regmap_pmu);
+		of_node_put(node);
+		if (IS_ERR(data->regmap_pmu)) {
+			ret = PTR_ERR(data->regmap_pmu);
+			goto err_edev;
+		}
 	}
 
 	regmap_read(data->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
@@ -391,7 +395,8 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 		data->odt_dis_freq = data->timing.lpddr4_odt_dis_freq;
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_edev;
 	};
 
 	arm_smccc_smc(ROCKCHIP_SIP_DRAM_FREQ, 0, 0,
@@ -425,7 +430,8 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 	 */
 	if (dev_pm_opp_of_add_table(dev)) {
 		dev_err(dev, "Invalid operating-points in device tree.\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_edev;
 	}
 
 	of_property_read_u32(np, "upthreshold",
@@ -465,6 +471,9 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 
 err_free_opp:
 	dev_pm_opp_of_remove_table(&pdev->dev);
+err_edev:
+	devfreq_event_disable_edev(data->edev);
+
 	return ret;
 }
 
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index fb376b5b7281..c6f82d4bec9f 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -108,6 +108,20 @@ struct devfreq_dev_profile {
 };
 
 /**
+ * struct devfreq_stats - Statistics of devfreq device behavior
+ * @total_trans:	Number of devfreq transitions.
+ * @trans_table:	Statistics of devfreq transitions.
+ * @time_in_state:	Statistics of devfreq states.
+ * @last_update:	The last time stats were updated.
+ */
+struct devfreq_stats {
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	u64 *time_in_state;
+	u64 last_update;
+};
+
+/**
  * struct devfreq - Device devfreq structure
  * @node:	list node - contains the devices with devfreq that have been
  *		registered.
@@ -122,6 +136,7 @@ struct devfreq_dev_profile {
  *		devfreq.nb to the corresponding register notifier call chain.
  * @work:	delayed work for load monitoring.
  * @previous_freq:	previously configured frequency value.
+ * @last_status:	devfreq user device info, performance statistics
  * @data:	Private data of the governor. The devfreq framework does not
  *		touch this.
  * @user_min_freq_req:	PM QoS minimum frequency request from user (via sysfs)
@@ -132,15 +147,12 @@ struct devfreq_dev_profile {
  * @suspend_freq:	 frequency of a device set during suspend phase.
  * @resume_freq:	 frequency of a device set in resume phase.
  * @suspend_count:	 suspend requests counter for a device.
- * @total_trans:	Number of devfreq transitions
- * @trans_table:	Statistics of devfreq transitions
- * @time_in_state:	Statistics of devfreq states
- * @last_stat_updated:	The last time stat updated
+ * @stats:	Statistics of devfreq device behavior
  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
  * @nb_min:		Notifier block for DEV_PM_QOS_MIN_FREQUENCY
  * @nb_max:		Notifier block for DEV_PM_QOS_MAX_FREQUENCY
  *
- * This structure stores the devfreq information for a give device.
+ * This structure stores the devfreq information for a given device.
  *
  * Note that when a governor accesses entries in struct devfreq in its
  * functions except for the context of callbacks defined in struct
@@ -174,11 +186,8 @@ struct devfreq {
 	unsigned long resume_freq;
 	atomic_t suspend_count;
 
-	/* information for device frequency transition */
-	unsigned int total_trans;
-	unsigned int *trans_table;
-	unsigned long *time_in_state;
-	unsigned long last_stat_updated;
+	/* information for device frequency transitions */
+	struct devfreq_stats stats;
 
 	struct srcu_notifier_head transition_notifier_list;