diff --git a/drivers/clk/tegra/Makefile b/drivers/clk/tegra/Makefile
index f7dfb72..47320ca 100644
--- a/drivers/clk/tegra/Makefile
+++ b/drivers/clk/tegra/Makefile
@@ -1,5 +1,6 @@
 obj-y					+= clk.o
 obj-y					+= clk-audio-sync.o
+obj-y					+= clk-dfll.o
 obj-y					+= clk-divider.o
 obj-y					+= clk-periph.o
 obj-y					+= clk-periph-gate.o
diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c
new file mode 100644
index 0000000..5eca4ff
--- /dev/null
+++ b/drivers/clk/tegra/clk-dfll.c
@@ -0,0 +1,1074 @@
+/*
+ * clk-dfll.c - Tegra DFLL clock source common code
+ *
+ * Copyright (C) 2012-2014 NVIDIA Corporation. All rights reserved.
+ *
+ * Aleksandr Frid <afrid@nvidia.com>
+ * Paul Walmsley <pwalmsley@nvidia.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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * This library is for the DVCO and DFLL IP blocks on the Tegra124
+ * SoC. These IP blocks together are also known at NVIDIA as
+ * "CL-DVFS". To try to avoid confusion, this code refers to them
+ * collectively as the "DFLL."
+ *
+ * The DFLL is a root clocksource which tolerates some amount of
+ * supply voltage noise. Tegra124 uses it to clock the fast CPU
+ * complex when the target CPU speed is above a particular rate. The
+ * DFLL can be operated in either open-loop mode or closed-loop mode.
+ * In open-loop mode, the DFLL generates an output clock appropriate
+ * to the supply voltage. In closed-loop mode, when configured with a
+ * target frequency, the DFLL minimizes supply voltage while
+ * delivering an average frequency equal to the target.
+ *
+ * Devices clocked by the DFLL must be able to tolerate frequency
+ * variation. In the case of the CPU, it's important to note that the
+ * CPU cycle time will vary. This has implications for
+ * performance-measurement code and any code that relies on the CPU
+ * cycle time to delay for a certain length of time.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/pm_runtime.h>
+#include <linux/seq_file.h>
+
+#include "clk-dfll.h"
+
+/*
+ * DFLL control registers - access via dfll_{readl,writel}
+ */
+
+/* DFLL_CTRL: DFLL control register */
+#define DFLL_CTRL			0x00
+#define DFLL_CTRL_MODE_MASK		0x03
+
+/* DFLL_CONFIG: DFLL sample rate control */
+#define DFLL_CONFIG			0x04
+#define DFLL_CONFIG_DIV_MASK		0xff
+#define DFLL_CONFIG_DIV_PRESCALE	32
+
+/* DFLL_PARAMS: tuning coefficients for closed loop integrator */
+#define DFLL_PARAMS			0x08
+#define DFLL_PARAMS_CG_SCALE		(0x1 << 24)
+#define DFLL_PARAMS_FORCE_MODE_SHIFT	22
+#define DFLL_PARAMS_FORCE_MODE_MASK	(0x3 << DFLL_PARAMS_FORCE_MODE_SHIFT)
+#define DFLL_PARAMS_CF_PARAM_SHIFT	16
+#define DFLL_PARAMS_CF_PARAM_MASK	(0x3f << DFLL_PARAMS_CF_PARAM_SHIFT)
+#define DFLL_PARAMS_CI_PARAM_SHIFT	8
+#define DFLL_PARAMS_CI_PARAM_MASK	(0x7 << DFLL_PARAMS_CI_PARAM_SHIFT)
+#define DFLL_PARAMS_CG_PARAM_SHIFT	0
+#define DFLL_PARAMS_CG_PARAM_MASK	(0xff << DFLL_PARAMS_CG_PARAM_SHIFT)
+
+/* DFLL_TUNE0: delay line configuration register 0 */
+#define DFLL_TUNE0			0x0c
+
+/* DFLL_TUNE1: delay line configuration register 1 */
+#define DFLL_TUNE1			0x10
+
+/* DFLL_FREQ_REQ: target DFLL frequency control */
+#define DFLL_FREQ_REQ			0x14
+#define DFLL_FREQ_REQ_FORCE_ENABLE	(0x1 << 28)
+#define DFLL_FREQ_REQ_FORCE_SHIFT	16
+#define DFLL_FREQ_REQ_FORCE_MASK	(0xfff << DFLL_FREQ_REQ_FORCE_SHIFT)
+#define FORCE_MAX			2047
+#define FORCE_MIN			-2048
+#define DFLL_FREQ_REQ_SCALE_SHIFT	8
+#define DFLL_FREQ_REQ_SCALE_MASK	(0xff << DFLL_FREQ_REQ_SCALE_SHIFT)
+#define DFLL_FREQ_REQ_SCALE_MAX		256
+#define DFLL_FREQ_REQ_FREQ_VALID	(0x1 << 7)
+#define DFLL_FREQ_REQ_MULT_SHIFT	0
+#define DFLL_FREQ_REG_MULT_MASK		(0x7f << DFLL_FREQ_REQ_MULT_SHIFT)
+#define FREQ_MAX			127
+
+/* DFLL_DROOP_CTRL: droop prevention control */
+#define DFLL_DROOP_CTRL			0x1c
+
+/* DFLL_OUTPUT_CFG: closed loop mode control registers */
+#define DFLL_OUTPUT_CFG		0x20
+#define DFLL_OUTPUT_CFG_I2C_ENABLE	(0x1 << 30)
+#define OUT_MASK			0x3f
+#define DFLL_OUTPUT_CFG_SAFE_SHIFT	24
+#define DFLL_OUTPUT_CFG_SAFE_MASK    \
+		(OUT_MASK << DFLL_OUTPUT_CFG_SAFE_SHIFT)
+#define DFLL_OUTPUT_CFG_MAX_SHIFT	16
+#define DFLL_OUTPUT_CFG_MAX_MASK     \
+		(OUT_MASK << DFLL_OUTPUT_CFG_MAX_SHIFT)
+#define DFLL_OUTPUT_CFG_MIN_SHIFT	8
+#define DFLL_OUTPUT_CFG_MIN_MASK     \
+		(OUT_MASK << DFLL_OUTPUT_CFG_MIN_SHIFT)
+#define DFLL_OUTPUT_CFG_PWM_DELTA	(0x1 << 7)
+#define DFLL_OUTPUT_CFG_PWM_ENABLE	(0x1 << 6)
+#define DFLL_OUTPUT_CFG_PWM_DIV_SHIFT 0
+#define DFLL_OUTPUT_CFG_PWM_DIV_MASK  \
+		(OUT_MASK << DFLL_OUTPUT_CFG_PWM_DIV_SHIFT)
+
+/* DFLL_OUTPUT_FORCE: closed loop mode voltage forcing control */
+#define DFLL_OUTPUT_FORCE		0x24
+#define DFLL_OUTPUT_FORCE_ENABLE	(0x1 << 6)
+#define DFLL_OUTPUT_FORCE_VALUE_SHIFT 0
+#define DFLL_OUTPUT_FORCE_VALUE_MASK  \
+		(OUT_MASK << DFLL_OUTPUT_FORCE_VALUE_SHIFT)
+
+/* DFLL_MONITOR_CTRL: internal monitor data source control */
+#define DFLL_MONITOR_CTRL		0x28
+#define DFLL_MONITOR_CTRL_FREQ		6
+
+/* DFLL_MONITOR_DATA: internal monitor data output */
+#define DFLL_MONITOR_DATA		0x2c
+#define DFLL_MONITOR_DATA_NEW_MASK	(0x1 << 16)
+#define DFLL_MONITOR_DATA_VAL_SHIFT	0
+#define DFLL_MONITOR_DATA_VAL_MASK	(0xFFFF << DFLL_MONITOR_DATA_VAL_SHIFT)
+
+/*
+ * I2C output control registers - access via dfll_i2c_{readl,writel}
+ */
+
+/* DFLL_I2C_CFG: I2C controller configuration register */
+#define DFLL_I2C_CFG			0x40
+#define DFLL_I2C_CFG_ARB_ENABLE		(0x1 << 20)
+#define DFLL_I2C_CFG_HS_CODE_SHIFT	16
+#define DFLL_I2C_CFG_HS_CODE_MASK	(0x7 << DFLL_I2C_CFG_HS_CODE_SHIFT)
+#define DFLL_I2C_CFG_PACKET_ENABLE	(0x1 << 15)
+#define DFLL_I2C_CFG_SIZE_SHIFT		12
+#define DFLL_I2C_CFG_SIZE_MASK		(0x7 << DFLL_I2C_CFG_SIZE_SHIFT)
+#define DFLL_I2C_CFG_SLAVE_ADDR_10	(0x1 << 10)
+#define DFLL_I2C_CFG_SLAVE_ADDR_SHIFT_7BIT	1
+#define DFLL_I2C_CFG_SLAVE_ADDR_SHIFT_10BIT	0
+#define DFLL_I2C_CFG_SLAVE_ADDR_MASK	(0x3ff << DFLL_I2C_CFG_SLAVE_ADDR_SHIFT)
+
+/* DFLL_I2C_VDD_REG_ADDR: PMIC I2C address for closed loop mode */
+#define DFLL_I2C_VDD_REG_ADDR	0x44
+
+/* DFLL_I2C_STS: I2C controller status */
+#define DFLL_I2C_STS			0x48
+#define DFLL_I2C_STS_I2C_LAST_SHIFT	1
+#define DFLL_I2C_STS_I2C_REQ_PENDING	0x1
+
+/* DFLL_INTR_STS: DFLL interrupt status register */
+#define DFLL_INTR_STS			0x5c
+
+/* DFLL_INTR_EN: DFLL interrupt enable register */
+#define DFLL_INTR_EN			0x60
+#define DFLL_INTR_MIN_MASK		0x1
+#define DFLL_INTR_MAX_MASK		0x2
+
+/*
+ * Integrated I2C controller registers - relative to td->i2c_controller_base
+ */
+
+/* DFLL_I2C_CLK_DIVISOR: I2C controller clock divisor */
+#define DFLL_I2C_CLK_DIVISOR		0x6c
+#define DFLL_I2C_CLK_DIVISOR_MASK	0xffff
+#define DFLL_I2C_CLK_DIVISOR_FS_SHIFT	16
+#define DFLL_I2C_CLK_DIVISOR_HS_SHIFT	0
+#define DFLL_I2C_CLK_DIVISOR_PREDIV	8
+#define DFLL_I2C_CLK_DIVISOR_HSMODE_PREDIV	12
+
+/*
+ * Other constants
+ */
+
+/* MAX_DFLL_VOLTAGES: number of LUT entries in the DFLL IP block */
+#define MAX_DFLL_VOLTAGES		33
+
+/*
+ * REF_CLK_CYC_PER_DVCO_SAMPLE: the number of ref_clk cycles that the hardware
+ *    integrates the DVCO counter over - used for debug rate monitoring and
+ *    droop control
+ */
+#define REF_CLK_CYC_PER_DVCO_SAMPLE	4
+
+/*
+ * REF_CLOCK_RATE: the DFLL reference clock rate currently supported by this
+ * driver, in Hz
+ */
+#define REF_CLOCK_RATE			51000000UL
+
+
+/**
+ * enum dfll_ctrl_mode - DFLL hardware operating mode
+ * @DFLL_UNINITIALIZED: (uninitialized state - not in hardware bitfield)
+ * @DFLL_DISABLED: DFLL not generating an output clock
+ * @DFLL_OPEN_LOOP: DVCO running, but DFLL not adjusting voltage
+ *
+ * The integer corresponding to the last two states, minus one, is
+ * written to the DFLL hardware to change operating modes.
+ */
+enum dfll_ctrl_mode {
+	DFLL_UNINITIALIZED = 0,
+	DFLL_DISABLED = 1,
+	DFLL_OPEN_LOOP = 2,
+};
+
+/**
+ * enum dfll_tune_range - voltage range that the driver believes it's in
+ * @DFLL_TUNE_UNINITIALIZED: DFLL tuning not yet programmed
+ * @DFLL_TUNE_LOW: DFLL in the low-voltage range (or open-loop mode)
+ *
+ * Some DFLL tuning parameters may need to change depending on the
+ * DVCO's voltage; these states represent the ranges that the driver
+ * supports. These are software states; these values are never
+ * written into registers.
+ */
+enum dfll_tune_range {
+	DFLL_TUNE_UNINITIALIZED = 0,
+	DFLL_TUNE_LOW = 1,
+};
+
+struct tegra_dfll {
+	struct device			*dev;
+	struct tegra_dfll_soc_data	*soc;
+
+	void __iomem			*base;
+	void __iomem			*i2c_base;
+	void __iomem			*i2c_controller_base;
+	void __iomem			*lut_base;
+
+	struct clk			*soc_clk;
+	struct clk			*ref_clk;
+	struct clk			*i2c_clk;
+	struct clk			*dfll_clk;
+	unsigned long			ref_rate;
+	unsigned long			i2c_clk_rate;
+	unsigned long			dvco_rate_min;
+
+	enum dfll_ctrl_mode		mode;
+	enum dfll_tune_range		tune_range;
+	struct dentry			*debugfs_dir;
+	struct clk_hw			dfll_clk_hw;
+	const char			*output_clock_name;
+
+	/* Parameters from DT */
+	u32				droop_ctrl;
+};
+
+#define clk_hw_to_dfll(_hw) container_of(_hw, struct tegra_dfll, dfll_clk_hw)
+
+/* mode_name: map numeric DFLL modes to names for friendly console messages */
+static const char * const mode_name[] = {
+	[DFLL_UNINITIALIZED] = "uninitialized",
+	[DFLL_DISABLED] = "disabled",
+	[DFLL_OPEN_LOOP] = "open_loop",
+};
+
+/*
+ * Register accessors
+ */
+
+static inline u32 dfll_readl(struct tegra_dfll *td, u32 offs)
+{
+	return __raw_readl(td->base + offs);
+}
+
+static inline void dfll_writel(struct tegra_dfll *td, u32 val, u32 offs)
+{
+	WARN_ON(offs >= DFLL_I2C_CFG);
+	__raw_writel(val, td->base + offs);
+}
+
+static inline void dfll_wmb(struct tegra_dfll *td)
+{
+	dfll_readl(td, DFLL_CTRL);
+}
+
+/* I2C output control registers - for addresses above DFLL_I2C_CFG */
+
+static inline u32 dfll_i2c_readl(struct tegra_dfll *td, u32 offs)
+{
+	return __raw_readl(td->i2c_base + offs);
+}
+
+static inline void dfll_i2c_writel(struct tegra_dfll *td, u32 val, u32 offs)
+{
+	__raw_writel(val, td->i2c_base + offs);
+}
+
+static inline void dfll_i2c_wmb(struct tegra_dfll *td)
+{
+	dfll_i2c_readl(td, DFLL_I2C_CFG);
+}
+
+/**
+ * dfll_is_running - is the DFLL currently generating a clock?
+ * @td: DFLL instance
+ *
+ * If the DFLL is currently generating an output clock signal, return
+ * true; otherwise return false.
+ */
+static bool dfll_is_running(struct tegra_dfll *td)
+{
+	return td->mode >= DFLL_OPEN_LOOP;
+}
+
+/*
+ * Runtime PM suspend/resume callbacks
+ */
+
+/**
+ * tegra_dfll_runtime_resume - enable all clocks needed by the DFLL
+ * @dev: DFLL device *
+ *
+ * Enable all clocks needed by the DFLL. Assumes that clk_prepare()
+ * has already been called on all the clocks.
+ *
+ * XXX Should also handle context restore when returning from off.
+ */
+int tegra_dfll_runtime_resume(struct device *dev)
+{
+	struct tegra_dfll *td = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_enable(td->i2c_clk);
+	if (ret) {
+		dev_err(dev, "could not enable I2C clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_enable(td->ref_clk);
+	if (ret) {
+		dev_err(dev, "could not enable ref clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_enable(td->soc_clk);
+	if (ret) {
+		dev_err(dev, "could not enable register clock: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_dfll_runtime_resume);
+
+/**
+ * tegra_dfll_runtime_suspend - disable all clocks needed by the DFLL
+ * @dev: DFLL device *
+ *
+ * Disable all clocks needed by the DFLL. Assumes that other code
+ * will later call clk_unprepare().
+ */
+int tegra_dfll_runtime_suspend(struct device *dev)
+{
+	struct tegra_dfll *td = dev_get_drvdata(dev);
+
+	clk_disable(td->soc_clk);
+	clk_disable(td->ref_clk);
+	clk_disable(td->i2c_clk);
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_dfll_runtime_suspend);
+
+/*
+ * DFLL tuning operations (per-voltage-range tuning settings)
+ */
+
+/**
+ * dfll_tune_low - tune to DFLL and CPU settings valid for any voltage
+ * @td: DFLL instance
+ *
+ * Tune the DFLL oscillator parameters and the CPU clock shaper for
+ * the low-voltage range. These settings are valid for any voltage,
+ * but may not be optimal.
+ */
+static void dfll_tune_low(struct tegra_dfll *td)
+{
+	td->tune_range = DFLL_TUNE_LOW;
+
+	dfll_writel(td, td->soc->tune0_low, DFLL_TUNE0);
+	dfll_writel(td, td->soc->tune1, DFLL_TUNE1);
+	dfll_wmb(td);
+
+	if (td->soc->set_clock_trimmers_low)
+		td->soc->set_clock_trimmers_low();
+}
+
+/*
+ * Output clock scaler helpers
+ */
+
+/**
+ * dfll_scale_dvco_rate - calculate scaled rate from the DVCO rate
+ * @scale_bits: clock scaler value (bits in the DFLL_FREQ_REQ_SCALE field)
+ * @dvco_rate: the DVCO rate
+ *
+ * Apply the same scaling formula that the DFLL hardware uses to scale
+ * the DVCO rate.
+ */
+static unsigned long dfll_scale_dvco_rate(int scale_bits,
+					  unsigned long dvco_rate)
+{
+	return (u64)dvco_rate * (scale_bits + 1) / DFLL_FREQ_REQ_SCALE_MAX;
+}
+
+/*
+ * Monitor control
+ */
+
+/**
+ * dfll_calc_monitored_rate - convert DFLL_MONITOR_DATA_VAL rate into real freq
+ * @monitor_data: value read from the DFLL_MONITOR_DATA_VAL bitfield
+ * @ref_rate: DFLL reference clock rate
+ *
+ * Convert @monitor_data from DFLL_MONITOR_DATA_VAL units into cycles
+ * per second. Returns the converted value.
+ */
+static u64 dfll_calc_monitored_rate(u32 monitor_data,
+				    unsigned long ref_rate)
+{
+	return monitor_data * (ref_rate / REF_CLK_CYC_PER_DVCO_SAMPLE);
+}
+
+/**
+ * dfll_read_monitor_rate - return the DFLL's output rate from internal monitor
+ * @td: DFLL instance
+ *
+ * If the DFLL is enabled, return the last rate reported by the DFLL's
+ * internal monitoring hardware. This works in both open-loop and
+ * closed-loop mode, and takes the output scaler setting into account.
+ * Assumes that the monitor was programmed to monitor frequency before
+ * the sample period started. If the driver believes that the DFLL is
+ * currently uninitialized or disabled, it will return 0, since
+ * otherwise the DFLL monitor data register will return the last
+ * measured rate from when the DFLL was active.
+ */
+static u64 dfll_read_monitor_rate(struct tegra_dfll *td)
+{
+	u32 v, s;
+	u64 pre_scaler_rate, post_scaler_rate;
+
+	if (!dfll_is_running(td))
+		return 0;
+
+	v = dfll_readl(td, DFLL_MONITOR_DATA);
+	v = (v & DFLL_MONITOR_DATA_VAL_MASK) >> DFLL_MONITOR_DATA_VAL_SHIFT;
+	pre_scaler_rate = dfll_calc_monitored_rate(v, td->ref_rate);
+
+	s = dfll_readl(td, DFLL_FREQ_REQ);
+	s = (s & DFLL_FREQ_REQ_SCALE_MASK) >> DFLL_FREQ_REQ_SCALE_SHIFT;
+	post_scaler_rate = dfll_scale_dvco_rate(pre_scaler_rate, s);
+
+	return post_scaler_rate;
+}
+
+/*
+ * DFLL mode switching
+ */
+
+/**
+ * dfll_set_mode - change the DFLL control mode
+ * @td: DFLL instance
+ * @mode: DFLL control mode (see enum dfll_ctrl_mode)
+ *
+ * Change the DFLL's operating mode between disabled, open-loop mode,
+ * and closed-loop mode, or vice versa.
+ */
+static void dfll_set_mode(struct tegra_dfll *td,
+			  enum dfll_ctrl_mode mode)
+{
+	td->mode = mode;
+	dfll_writel(td, mode - 1, DFLL_CTRL);
+	dfll_wmb(td);
+}
+
+/*
+ * DFLL enable/disable & open-loop <-> closed-loop transitions
+ */
+
+/**
+ * dfll_disable - switch from open-loop mode to disabled mode
+ * @td: DFLL instance
+ *
+ * Switch from OPEN_LOOP state to DISABLED state. Returns 0 upon success
+ * or -EPERM if the DFLL is not currently in open-loop mode.
+ */
+static int dfll_disable(struct tegra_dfll *td)
+{
+	if (td->mode != DFLL_OPEN_LOOP) {
+		dev_err(td->dev, "cannot disable DFLL in %s mode\n",
+			mode_name[td->mode]);
+		return -EINVAL;
+	}
+
+	dfll_set_mode(td, DFLL_DISABLED);
+	pm_runtime_put_sync(td->dev);
+
+	return 0;
+}
+
+/**
+ * dfll_enable - switch a disabled DFLL to open-loop mode
+ * @td: DFLL instance
+ *
+ * Switch from DISABLED state to OPEN_LOOP state. Returns 0 upon success
+ * or -EPERM if the DFLL is not currently disabled.
+ */
+static int dfll_enable(struct tegra_dfll *td)
+{
+	if (td->mode != DFLL_DISABLED) {
+		dev_err(td->dev, "cannot enable DFLL in %s mode\n",
+			mode_name[td->mode]);
+		return -EPERM;
+	}
+
+	pm_runtime_get_sync(td->dev);
+	dfll_set_mode(td, DFLL_OPEN_LOOP);
+
+	return 0;
+}
+
+/**
+ * dfll_set_open_loop_config - prepare to switch to open-loop mode
+ * @td: DFLL instance
+ *
+ * Prepare to switch the DFLL to open-loop mode. This switches the
+ * DFLL to the low-voltage tuning range, ensures that I2C output
+ * forcing is disabled, and disables the output clock rate scaler.
+ * The DFLL's low-voltage tuning range parameters must be
+ * characterized to keep the downstream device stable at any DVCO
+ * input voltage. No return value.
+ */
+static void dfll_set_open_loop_config(struct tegra_dfll *td)
+{
+	u32 val;
+
+	/* always tune low (safe) in open loop */
+	if (td->tune_range != DFLL_TUNE_LOW)
+		dfll_tune_low(td);
+
+	val = dfll_readl(td, DFLL_FREQ_REQ);
+	val |= DFLL_FREQ_REQ_SCALE_MASK;
+	val &= ~DFLL_FREQ_REQ_FORCE_ENABLE;
+	dfll_writel(td, val, DFLL_FREQ_REQ);
+}
+
+/*
+ * Clock framework integration
+ */
+
+static int dfll_clk_is_enabled(struct clk_hw *hw)
+{
+	struct tegra_dfll *td = clk_hw_to_dfll(hw);
+
+	return dfll_is_running(td);
+}
+
+static int dfll_clk_enable(struct clk_hw *hw)
+{
+	struct tegra_dfll *td = clk_hw_to_dfll(hw);
+
+	return dfll_enable(td);
+}
+
+static void dfll_clk_disable(struct clk_hw *hw)
+{
+	struct tegra_dfll *td = clk_hw_to_dfll(hw);
+
+	dfll_disable(td);
+}
+
+static const struct clk_ops dfll_clk_ops = {
+	.is_enabled	= dfll_clk_is_enabled,
+	.enable		= dfll_clk_enable,
+	.disable	= dfll_clk_disable,
+};
+
+static struct clk_init_data dfll_clk_init_data = {
+	.flags		= CLK_IS_ROOT,
+	.ops		= &dfll_clk_ops,
+	.num_parents	= 0,
+};
+
+/**
+ * dfll_register_clk - register the DFLL output clock with the clock framework
+ * @td: DFLL instance
+ *
+ * Register the DFLL's output clock with the Linux clock framework and register
+ * the DFLL driver as an OF clock provider. Returns 0 upon success or -EINVAL
+ * upon failure.
+ */
+static int dfll_register_clk(struct tegra_dfll *td)
+{
+	int ret;
+
+	dfll_clk_init_data.name = td->output_clock_name;
+	td->dfll_clk_hw.init = &dfll_clk_init_data;
+
+	td->dfll_clk = clk_register(td->dev, &td->dfll_clk_hw);
+	if (IS_ERR(td->dfll_clk)) {
+		dev_err(td->dev, "DFLL clock registration error\n");
+		return -EINVAL;
+	}
+
+	ret = of_clk_add_provider(td->dev->of_node, of_clk_src_simple_get,
+				  td->dfll_clk);
+	if (ret) {
+		dev_err(td->dev, "of_clk_add_provider() failed\n");
+		goto out_unregister_clk;
+	}
+
+	return 0;
+
+out_unregister_clk:
+	clk_unregister(td->dfll_clk);
+
+	return ret;
+}
+
+/**
+ * dfll_unregister_clk - unregister the DFLL output clock
+ * @td: DFLL instance
+ *
+ * Unregister the DFLL's output clock from the Linux clock framework
+ * and from clkdev. No return value.
+ */
+static void dfll_unregister_clk(struct tegra_dfll *td)
+{
+	of_clk_del_provider(td->dev->of_node);
+	clk_unregister(td->dfll_clk);
+	td->dfll_clk = NULL;
+}
+
+/*
+ * Debugfs interface
+ */
+
+#ifdef CONFIG_DEBUG_FS
+
+static int attr_enable_get(void *data, u64 *val)
+{
+	struct tegra_dfll *td = data;
+
+	*val = dfll_is_running(td);
+
+	return 0;
+}
+static int attr_enable_set(void *data, u64 val)
+{
+	struct tegra_dfll *td = data;
+
+	return val ? dfll_enable(td) : dfll_disable(td);
+}
+DEFINE_SIMPLE_ATTRIBUTE(enable_fops, attr_enable_get, attr_enable_set,
+			"%llu\n");
+
+static int attr_rate_get(void *data, u64 *val)
+{
+	struct tegra_dfll *td = data;
+
+	*val = dfll_read_monitor_rate(td);
+
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(rate_fops, attr_rate_get, NULL, "%llu\n");
+
+static int attr_registers_show(struct seq_file *s, void *data)
+{
+	u32 offs;
+	struct tegra_dfll *td = s->private;
+
+	seq_puts(s, "CONTROL REGISTERS:\n");
+	for (offs = 0; offs <= DFLL_MONITOR_DATA; offs += 4)
+		seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
+			   dfll_readl(td, offs));
+
+	seq_puts(s, "\nI2C and INTR REGISTERS:\n");
+	for (offs = DFLL_I2C_CFG; offs <= DFLL_I2C_STS; offs += 4)
+		seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
+			   dfll_i2c_readl(td, offs));
+	for (offs = DFLL_INTR_STS; offs <= DFLL_INTR_EN; offs += 4)
+		seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
+			   dfll_i2c_readl(td, offs));
+
+	seq_puts(s, "\nINTEGRATED I2C CONTROLLER REGISTERS:\n");
+	offs = DFLL_I2C_CLK_DIVISOR;
+	seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
+		   __raw_readl(td->i2c_controller_base + offs));
+
+	seq_puts(s, "\nLUT:\n");
+	for (offs = 0; offs <  4 * MAX_DFLL_VOLTAGES; offs += 4)
+		seq_printf(s, "[0x%02x] = 0x%08x\n", offs,
+			   __raw_readl(td->lut_base + offs));
+
+	return 0;
+}
+
+static int attr_registers_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, attr_registers_show, inode->i_private);
+}
+
+static const struct file_operations attr_registers_fops = {
+	.open		= attr_registers_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int dfll_debug_init(struct tegra_dfll *td)
+{
+	int ret;
+
+	if (!td || (td->mode == DFLL_UNINITIALIZED))
+		return 0;
+
+	td->debugfs_dir = debugfs_create_dir("tegra_dfll_fcpu", NULL);
+	if (!td->debugfs_dir)
+		return -ENOMEM;
+
+	ret = -ENOMEM;
+
+	if (!debugfs_create_file("enable", S_IRUGO | S_IWUSR,
+				 td->debugfs_dir, td, &enable_fops))
+		goto err_out;
+
+	if (!debugfs_create_file("rate", S_IRUGO,
+				 td->debugfs_dir, td, &rate_fops))
+		goto err_out;
+
+	if (!debugfs_create_file("registers", S_IRUGO,
+				 td->debugfs_dir, td, &attr_registers_fops))
+		goto err_out;
+
+	return 0;
+
+err_out:
+	debugfs_remove_recursive(td->debugfs_dir);
+	return ret;
+}
+
+#endif /* CONFIG_DEBUG_FS */
+
+/*
+ * DFLL initialization
+ */
+
+/**
+ * dfll_set_default_params - program non-output related DFLL parameters
+ * @td: DFLL instance
+ *
+ * During DFLL driver initialization or resume from context loss,
+ * program parameters for the closed loop integrator, DVCO tuning,
+ * voltage droop control and monitor control.
+ */
+static void dfll_set_default_params(struct tegra_dfll *td)
+{
+	dfll_tune_low(td);
+	dfll_writel(td, td->droop_ctrl, DFLL_DROOP_CTRL);
+	dfll_writel(td, DFLL_MONITOR_CTRL_FREQ, DFLL_MONITOR_CTRL);
+}
+
+/**
+ * dfll_init_clks - clk_get() the DFLL source clocks
+ * @td: DFLL instance
+ *
+ * Call clk_get() on the DFLL source clocks and save the pointers for later
+ * use. Returns 0 upon success or -ENODEV if one or more of the clocks
+ * couldn't be looked up.
+ */
+static int dfll_init_clks(struct tegra_dfll *td)
+{
+	td->ref_clk = devm_clk_get(td->dev, "ref");
+	if (IS_ERR(td->ref_clk)) {
+		dev_err(td->dev, "missing ref clock\n");
+		return PTR_ERR(td->ref_clk);
+	}
+
+	td->soc_clk = devm_clk_get(td->dev, "soc");
+	if (IS_ERR(td->soc_clk)) {
+		dev_err(td->dev, "missing soc clock\n");
+		return PTR_ERR(td->soc_clk);
+	}
+
+	td->i2c_clk = devm_clk_get(td->dev, "i2c");
+	if (IS_ERR(td->i2c_clk)) {
+		dev_err(td->dev, "missing i2c clock\n");
+		return PTR_ERR(td->i2c_clk);
+	}
+	td->i2c_clk_rate = clk_get_rate(td->i2c_clk);
+
+	return 0;
+}
+
+/**
+ * dfll_init - Prepare the DFLL IP block for use
+ * @td: DFLL instance
+ *
+ * Do everything necessary to prepare the DFLL IP block for use. The
+ * DFLL will be left in DISABLED state. Called by dfll_probe().
+ * Returns 0 upon success, or passes along the error from whatever
+ * function returned it.
+ */
+static int dfll_init(struct tegra_dfll *td)
+{
+	int ret;
+
+	td->ref_rate = clk_get_rate(td->ref_clk);
+	if (td->ref_rate != REF_CLOCK_RATE) {
+		dev_err(td->dev, "unexpected ref clk rate %lu, expecting %lu",
+			td->ref_rate, REF_CLOCK_RATE);
+		return -EINVAL;
+	}
+
+	if (td->soc->deassert_dvco_reset)
+		td->soc->deassert_dvco_reset();
+
+	ret = clk_prepare(td->i2c_clk);
+	if (ret) {
+		dev_err(td->dev, "failed to prepare i2c_clk\n");
+		return ret;
+	}
+
+	ret = clk_prepare(td->ref_clk);
+	if (ret) {
+		dev_err(td->dev, "failed to prepare ref_clk\n");
+		goto di_err1;
+	}
+
+	ret = clk_prepare(td->soc_clk);
+	if (ret) {
+		dev_err(td->dev, "failed to prepare soc_clk\n");
+		goto di_err2;
+	}
+
+	pm_runtime_enable(td->dev);
+	pm_runtime_get_sync(td->dev);
+
+	dfll_set_mode(td, DFLL_DISABLED);
+	dfll_set_default_params(td);
+
+	if (td->soc->init_clock_trimmers)
+		td->soc->init_clock_trimmers();
+
+	dfll_set_open_loop_config(td);
+
+	pm_runtime_put_sync(td->dev);
+
+	return 0;
+
+di_err2:
+	clk_unprepare(td->ref_clk);
+di_err1:
+	clk_unprepare(td->i2c_clk);
+
+	if (td->soc->assert_dvco_reset)
+		td->soc->assert_dvco_reset();
+
+	return ret;
+}
+
+/*
+ * DT data fetch
+ */
+
+/**
+ * read_dt_param - helper function for reading required parameters from the DT
+ * @td: DFLL instance
+ * @param: DT property name
+ * @dest: output pointer for the value read
+ *
+ * Read a required numeric parameter from the DFLL device node, or complain
+ * if the property doesn't exist. Returns a boolean indicating success for
+ * easy chaining of multiple calls to this function.
+ */
+static bool read_dt_param(struct tegra_dfll *td, const char *param, u32 *dest)
+{
+	int err = of_property_read_u32(td->dev->of_node, param, dest);
+
+	if (err < 0) {
+		dev_err(td->dev, "failed to read DT parameter %s: %d\n",
+			param, err);
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * dfll_parse_dt_params - read DFLL parameters from the device tree
+ * @td: DFLL instance
+ *
+ * Read all the required parameters for the DFLL from the device tree.
+ * Returns 0 on success or -EINVAL on any failure.
+ */
+static int dfll_parse_dt_params(struct tegra_dfll *td)
+{
+	bool ok = true;
+
+	ok &= read_dt_param(td, "nvidia,droop-ctrl", &td->droop_ctrl);
+
+	if (of_property_read_string(td->dev->of_node, "clock-output-names",
+				    &td->output_clock_name)) {
+		dev_err(td->dev, "missing clock-output-names property\n");
+		ok = false;
+	}
+
+	return ok ? 0 : -EINVAL;
+}
+
+/*
+ * API exported to per-SoC platform drivers
+ */
+
+/**
+ * tegra_dfll_register - probe a Tegra DFLL device
+ * @pdev: DFLL platform_device *
+ * @soc: Per-SoC integration and characterization data for this DFLL instance
+ *
+ * Probe and initialize a DFLL device instance. Intended to be called
+ * by a SoC-specific shim driver that passes in per-SoC integration
+ * and configuration data via @soc. Returns 0 on success or -err on failure.
+ */
+int tegra_dfll_register(struct platform_device *pdev,
+			struct tegra_dfll_soc_data *soc)
+{
+	struct resource *mem;
+	struct tegra_dfll *td;
+	int ret;
+
+	td = devm_kzalloc(&pdev->dev, sizeof(*td), GFP_KERNEL);
+	if (!td)
+		return -ENOMEM;
+	td->dev = &pdev->dev;
+	platform_set_drvdata(pdev, td);
+
+	if (!soc) {
+		dev_err(td->dev, "no tegra_dfll_soc_data provided\n");
+		return -EINVAL;
+	}
+	td->soc = soc;
+
+	ret = dfll_parse_dt_params(td);
+	if (ret) {
+		dev_err(td->dev, "couldn't parse device tree parameters\n");
+		return ret;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(td->dev, "no control register resource\n");
+		return -ENODEV;
+	}
+
+	td->base = devm_ioremap(td->dev, mem->start, resource_size(mem));
+	if (!td->base) {
+		dev_err(td->dev, "couldn't ioremap DFLL control registers\n");
+		return -ENODEV;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!mem) {
+		dev_err(td->dev, "no i2c_base resource\n");
+		return -ENODEV;
+	}
+
+	td->i2c_base = devm_ioremap(td->dev, mem->start, resource_size(mem));
+	if (!td->i2c_base) {
+		dev_err(td->dev, "couldn't ioremap i2c_base resource\n");
+		return -ENODEV;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	if (!mem) {
+		dev_err(td->dev, "no i2c_controller_base resource\n");
+		return -ENODEV;
+	}
+
+	td->i2c_controller_base = devm_ioremap(td->dev, mem->start,
+					       resource_size(mem));
+	if (!td->i2c_controller_base) {
+		dev_err(td->dev,
+			"couldn't ioremap i2c_controller_base resource\n");
+		return -ENODEV;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+	if (!mem) {
+		dev_err(td->dev, "no lut_base resource\n");
+		return -ENODEV;
+	}
+
+	td->lut_base = devm_ioremap(td->dev, mem->start, resource_size(mem));
+	if (!td->lut_base) {
+		dev_err(td->dev,
+			"couldn't ioremap lut_base resource\n");
+		return -ENODEV;
+	}
+
+	ret = dfll_init_clks(td);
+	if (ret) {
+		dev_err(&pdev->dev, "DFLL clock init error\n");
+		return ret;
+	}
+
+	/* Enable the clocks and set the device up */
+	ret = dfll_init(td);
+	if (ret)
+		return ret;
+
+	ret = dfll_register_clk(td);
+	if (ret) {
+		dev_err(&pdev->dev, "DFLL clk registration failed\n");
+		return ret;
+	}
+
+#ifdef CONFIG_DEBUG_FS
+	dfll_debug_init(td);
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_dfll_register);
+
+/**
+ * tegra_dfll_unregister - release all of the DFLL driver resources for a device
+ * @pdev: DFLL platform_device *
+ *
+ * Unbind this driver from the DFLL hardware device represented by
+ * @pdev. The DFLL must be disabled for this to succeed. Returns 0
+ * upon success or -EBUSY if the DFLL is still active.
+ */
+int tegra_dfll_unregister(struct platform_device *pdev)
+{
+	struct tegra_dfll *td = platform_get_drvdata(pdev);
+
+	/* Try to prevent removal while the DFLL is active */
+	if (td->mode != DFLL_DISABLED) {
+		dev_err(&pdev->dev,
+			"must disable DFLL before removing driver\n");
+		return -EBUSY;
+	}
+
+	debugfs_remove_recursive(td->debugfs_dir);
+
+	dfll_unregister_clk(td);
+	pm_runtime_disable(&pdev->dev);
+
+	clk_unprepare(td->soc_clk);
+	clk_unprepare(td->ref_clk);
+	clk_unprepare(td->i2c_clk);
+
+	if (td->soc->assert_dvco_reset)
+		td->soc->assert_dvco_reset();
+
+	return 0;
+}
+EXPORT_SYMBOL(tegra_dfll_unregister);
diff --git a/drivers/clk/tegra/clk-dfll.h b/drivers/clk/tegra/clk-dfll.h
new file mode 100644
index 0000000..fbf90c4
--- /dev/null
+++ b/drivers/clk/tegra/clk-dfll.h
@@ -0,0 +1,55 @@
+/*
+ * clk-dfll.h - prototypes and macros for the Tegra DFLL clocksource driver
+ * Copyright (C) 2013 NVIDIA Corporation.  All rights reserved.
+ *
+ * Aleksandr Frid <afrid@nvidia.com>
+ * Paul Walmsley <pwalmsley@nvidia.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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef __DRIVERS_CLK_TEGRA_CLK_DFLL_H
+#define __DRIVERS_CLK_TEGRA_CLK_DFLL_H
+
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+/**
+ * struct tegra_dfll_soc - SoC-specific hooks/integration for the DFLL driver
+ * @opp_dev: struct device * that holds the OPP table for the DFLL
+ * @min_millivolts: minimum voltage (in mV) that the DFLL can operate
+ * @tune0_low: DFLL tuning register 0 (low voltage range)
+ * @tune0_high: DFLL tuning register 0 (high voltage range)
+ * @tune1: DFLL tuning register 1
+ * @assert_dvco_reset: fn ptr to place the DVCO in reset
+ * @deassert_dvco_reset: fn ptr to release the DVCO reset
+ * @set_clock_trimmers_high: fn ptr to tune clock trimmers for high voltage
+ * @set_clock_trimmers_low: fn ptr to tune clock trimmers for low voltage
+ */
+struct tegra_dfll_soc_data {
+	struct device *opp_dev;
+	unsigned int min_millivolts;
+	u32 tune0_low;
+	u32 tune0_high;
+	u32 tune1;
+	void (*assert_dvco_reset)(void);
+	void (*deassert_dvco_reset)(void);
+	void (*init_clock_trimmers)(void);
+	void (*set_clock_trimmers_high)(void);
+	void (*set_clock_trimmers_low)(void);
+};
+
+int tegra_dfll_register(struct platform_device *pdev,
+			struct tegra_dfll_soc_data *soc);
+int tegra_dfll_unregister(struct platform_device *pdev);
+int tegra_dfll_runtime_suspend(struct device *dev);
+int tegra_dfll_runtime_resume(struct device *dev);
+
+#endif /* __DRIVERS_CLK_TEGRA_CLK_DFLL_H */
