Merge tag 'common-clk-api' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull "drivers/clk: common clock framework" from Olof Johansson:
 "This branch contains patches from Mike Turquette adding a common clock
  framework to be shared across platforms.  This is part of the work
  towards building a common zImage for several ARM platforms."

* tag 'common-clk-api' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  clk: make CONFIG_COMMON_CLK invisible
  clk: basic clock hardware types
  clk: introduce the common clock framework
  Documentation: common clk API

7 files changed, 2048 insertions, 0 deletions

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 9b3cd08cd0e..165e1febae5 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -8,3 +8,40 @@ config HAVE_CLK_PREPARE
 
 config HAVE_MACH_CLKDEV
 	bool
+
+config COMMON_CLK
+	bool
+	select HAVE_CLK_PREPARE
+	---help---
+	  The common clock framework is a single definition of struct
+	  clk, useful across many platforms, as well as an
+	  implementation of the clock API in include/linux/clk.h.
+	  Architectures utilizing the common struct clk should select
+	  this option.
+
+menu "Common Clock Framework"
+	depends on COMMON_CLK
+
+config COMMON_CLK_DISABLE_UNUSED
+	bool "Disabled unused clocks at boot"
+	depends on COMMON_CLK
+	---help---
+	  Traverses the entire clock tree and disables any clocks that are
+	  enabled in hardware but have not been enabled by any device drivers.
+	  This saves power and keeps the software model of the clock in line
+	  with reality.
+
+	  If in doubt, say "N".
+
+config COMMON_CLK_DEBUG
+	bool "DebugFS representation of clock tree"
+	depends on COMMON_CLK
+	select DEBUG_FS
+	---help---
+	  Creates a directory hierchy in debugfs for visualizing the clk
+	  tree structure.  Each directory contains read-only members
+	  that export information specific to that clk node: clk_rate,
+	  clk_flags, clk_prepare_count, clk_enable_count &
+	  clk_notifier_count.
+
+endmenu
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 07613fa172c..1f736bc11c4 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -1,2 +1,4 @@
 
 obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
+obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
+				   clk-mux.o clk-divider.o
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
new file mode 100644
index 00000000000..d5ac6a75ea5
--- /dev/null
+++ b/drivers/clk/clk-divider.c
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Adjustable divider clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+/*
+ * DOC: basic adjustable divider clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable.  clk->rate = parent->rate / divisor
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw)
+
+#define div_mask(d)	((1 << (d->width)) - 1)
+
+static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	unsigned int div;
+
+	div = readl(divider->reg) >> divider->shift;
+	div &= div_mask(divider);
+
+	if (!(divider->flags & CLK_DIVIDER_ONE_BASED))
+		div++;
+
+	return parent_rate / div;
+}
+EXPORT_SYMBOL_GPL(clk_divider_recalc_rate);
+
+/*
+ * The reverse of DIV_ROUND_UP: The maximum number which
+ * divided by m is r
+ */
+#define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)
+
+static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
+		unsigned long *best_parent_rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	int i, bestdiv = 0;
+	unsigned long parent_rate, best = 0, now, maxdiv;
+
+	if (!rate)
+		rate = 1;
+
+	maxdiv = (1 << divider->width);
+
+	if (divider->flags & CLK_DIVIDER_ONE_BASED)
+		maxdiv--;
+
+	if (!best_parent_rate) {
+		parent_rate = __clk_get_rate(__clk_get_parent(hw->clk));
+		bestdiv = DIV_ROUND_UP(parent_rate, rate);
+		bestdiv = bestdiv == 0 ? 1 : bestdiv;
+		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
+		return bestdiv;
+	}
+
+	/*
+	 * The maximum divider we can use without overflowing
+	 * unsigned long in rate * i below
+	 */
+	maxdiv = min(ULONG_MAX / rate, maxdiv);
+
+	for (i = 1; i <= maxdiv; i++) {
+		parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
+				MULT_ROUND_UP(rate, i));
+		now = parent_rate / i;
+		if (now <= rate && now > best) {
+			bestdiv = i;
+			best = now;
+			*best_parent_rate = parent_rate;
+		}
+	}
+
+	if (!bestdiv) {
+		bestdiv = (1 << divider->width);
+		if (divider->flags & CLK_DIVIDER_ONE_BASED)
+			bestdiv--;
+		*best_parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), 1);
+	}
+
+	return bestdiv;
+}
+
+static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *prate)
+{
+	int div;
+	div = clk_divider_bestdiv(hw, rate, prate);
+
+	if (prate)
+		return *prate / div;
+	else {
+		unsigned long r;
+		r = __clk_get_rate(__clk_get_parent(hw->clk));
+		return r / div;
+	}
+}
+EXPORT_SYMBOL_GPL(clk_divider_round_rate);
+
+static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate)
+{
+	struct clk_divider *divider = to_clk_divider(hw);
+	unsigned int div;
+	unsigned long flags = 0;
+	u32 val;
+
+	div = __clk_get_rate(__clk_get_parent(hw->clk)) / rate;
+
+	if (!(divider->flags & CLK_DIVIDER_ONE_BASED))
+		div--;
+
+	if (div > div_mask(divider))
+		div = div_mask(divider);
+
+	if (divider->lock)
+		spin_lock_irqsave(divider->lock, flags);
+
+	val = readl(divider->reg);
+	val &= ~(div_mask(divider) << divider->shift);
+	val |= div << divider->shift;
+	writel(val, divider->reg);
+
+	if (divider->lock)
+		spin_unlock_irqrestore(divider->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_divider_set_rate);
+
+struct clk_ops clk_divider_ops = {
+	.recalc_rate = clk_divider_recalc_rate,
+	.round_rate = clk_divider_round_rate,
+	.set_rate = clk_divider_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_divider_ops);
+
+struct clk *clk_register_divider(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags, spinlock_t *lock)
+{
+	struct clk_divider *div;
+	struct clk *clk;
+
+	div = kzalloc(sizeof(struct clk_divider), GFP_KERNEL);
+
+	if (!div) {
+		pr_err("%s: could not allocate divider clk\n", __func__);
+		return NULL;
+	}
+
+	/* struct clk_divider assignments */
+	div->reg = reg;
+	div->shift = shift;
+	div->width = width;
+	div->flags = clk_divider_flags;
+	div->lock = lock;
+
+	if (parent_name) {
+		div->parent[0] = kstrdup(parent_name, GFP_KERNEL);
+		if (!div->parent[0])
+			goto out;
+	}
+
+	clk = clk_register(dev, name,
+			&clk_divider_ops, &div->hw,
+			div->parent,
+			(parent_name ? 1 : 0),
+			flags);
+	if (clk)
+		return clk;
+
+out:
+	kfree(div->parent[0]);
+	kfree(div);
+
+	return NULL;
+}
diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c
new file mode 100644
index 00000000000..90c79fb5d1b
--- /dev/null
+++ b/drivers/clk/clk-fixed-rate.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Fixed rate clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+/*
+ * DOC: basic fixed-rate clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parents are prepared
+ * enable - clk_enable only ensures parents are enabled
+ * rate - rate is always a fixed value.  No clk_set_rate support
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
+
+static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	return to_clk_fixed_rate(hw)->fixed_rate;
+}
+EXPORT_SYMBOL_GPL(clk_fixed_rate_recalc_rate);
+
+struct clk_ops clk_fixed_rate_ops = {
+	.recalc_rate = clk_fixed_rate_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
+
+struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned long fixed_rate)
+{
+	struct clk_fixed_rate *fixed;
+	char **parent_names = NULL;
+	u8 len;
+
+	fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
+
+	if (!fixed) {
+		pr_err("%s: could not allocate fixed clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* struct clk_fixed_rate assignments */
+	fixed->fixed_rate = fixed_rate;
+
+	if (parent_name) {
+		parent_names = kmalloc(sizeof(char *), GFP_KERNEL);
+
+		if (! parent_names)
+			goto out;
+
+		len = sizeof(char) * strlen(parent_name);
+
+		parent_names[0] = kmalloc(len, GFP_KERNEL);
+
+		if (!parent_names[0])
+			goto out;
+
+		strncpy(parent_names[0], parent_name, len);
+	}
+
+out:
+	return clk_register(dev, name,
+			&clk_fixed_rate_ops, &fixed->hw,
+			parent_names,
+			(parent_name ? 1 : 0),
+			flags);
+}
diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
new file mode 100644
index 00000000000..b5902e2ef2f
--- /dev/null
+++ b/drivers/clk/clk-gate.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Gated clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+/**
+ * DOC: basic gatable clock which can gate and ungate it's ouput
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parent is (un)prepared
+ * enable - clk_enable and clk_disable are functional & control gating
+ * rate - inherits rate from parent.  No clk_set_rate support
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
+
+static void clk_gate_set_bit(struct clk_gate *gate)
+{
+	u32 reg;
+	unsigned long flags = 0;
+
+	if (gate->lock)
+		spin_lock_irqsave(gate->lock, flags);
+
+	reg = readl(gate->reg);
+	reg |= BIT(gate->bit_idx);
+	writel(reg, gate->reg);
+
+	if (gate->lock)
+		spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static void clk_gate_clear_bit(struct clk_gate *gate)
+{
+	u32 reg;
+	unsigned long flags = 0;
+
+	if (gate->lock)
+		spin_lock_irqsave(gate->lock, flags);
+
+	reg = readl(gate->reg);
+	reg &= ~BIT(gate->bit_idx);
+	writel(reg, gate->reg);
+
+	if (gate->lock)
+		spin_unlock_irqrestore(gate->lock, flags);
+}
+
+static int clk_gate_enable(struct clk_hw *hw)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+
+	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+		clk_gate_clear_bit(gate);
+	else
+		clk_gate_set_bit(gate);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_gate_enable);
+
+static void clk_gate_disable(struct clk_hw *hw)
+{
+	struct clk_gate *gate = to_clk_gate(hw);
+
+	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+		clk_gate_set_bit(gate);
+	else
+		clk_gate_clear_bit(gate);
+}
+EXPORT_SYMBOL_GPL(clk_gate_disable);
+
+static int clk_gate_is_enabled(struct clk_hw *hw)
+{
+	u32 reg;
+	struct clk_gate *gate = to_clk_gate(hw);
+
+	reg = readl(gate->reg);
+
+	/* if a set bit disables this clk, flip it before masking */
+	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
+		reg ^= BIT(gate->bit_idx);
+
+	reg &= BIT(gate->bit_idx);
+
+	return reg ? 1 : 0;
+}
+EXPORT_SYMBOL_GPL(clk_gate_is_enabled);
+
+struct clk_ops clk_gate_ops = {
+	.enable = clk_gate_enable,
+	.disable = clk_gate_disable,
+	.is_enabled = clk_gate_is_enabled,
+};
+EXPORT_SYMBOL_GPL(clk_gate_ops);
+
+struct clk *clk_register_gate(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 bit_idx,
+		u8 clk_gate_flags, spinlock_t *lock)
+{
+	struct clk_gate *gate;
+	struct clk *clk;
+
+	gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
+
+	if (!gate) {
+		pr_err("%s: could not allocate gated clk\n", __func__);
+		return NULL;
+	}
+
+	/* struct clk_gate assignments */
+	gate->reg = reg;
+	gate->bit_idx = bit_idx;
+	gate->flags = clk_gate_flags;
+	gate->lock = lock;
+
+	if (parent_name) {
+		gate->parent[0] = kstrdup(parent_name, GFP_KERNEL);
+		if (!gate->parent[0])
+			goto out;
+	}
+
+	clk = clk_register(dev, name,
+			&clk_gate_ops, &gate->hw,
+			gate->parent,
+			(parent_name ? 1 : 0),
+			flags);
+	if (clk)
+		return clk;
+out:
+	kfree(gate->parent[0]);
+	kfree(gate);
+
+	return NULL;
+}
diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
new file mode 100644
index 00000000000..c71ad1f41a9
--- /dev/null
+++ b/drivers/clk/clk-mux.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Simple multiplexer clock implementation
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+
+/*
+ * DOC: basic adjustable multiplexer clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is only affected by parent switching.  No clk_set_rate support
+ * parent - parent is adjustable through clk_set_parent
+ */
+
+#define to_clk_mux(_hw) container_of(_hw, struct clk_mux, hw)
+
+static u8 clk_mux_get_parent(struct clk_hw *hw)
+{
+	struct clk_mux *mux = to_clk_mux(hw);
+	u32 val;
+
+	/*
+	 * FIXME need a mux-specific flag to determine if val is bitwise or numeric
+	 * e.g. sys_clkin_ck's clksel field is 3 bits wide, but ranges from 0x1
+	 * to 0x7 (index starts at one)
+	 * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
+	 * val = 0x4 really means "bit 2, index starts at bit 0"
+	 */
+	val = readl(mux->reg) >> mux->shift;
+	val &= (1 << mux->width) - 1;
+
+	if (val && (mux->flags & CLK_MUX_INDEX_BIT))
+		val = ffs(val) - 1;
+
+	if (val && (mux->flags & CLK_MUX_INDEX_ONE))
+		val--;
+
+	if (val >= __clk_get_num_parents(hw->clk))
+		return -EINVAL;
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(clk_mux_get_parent);
+
+static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_mux *mux = to_clk_mux(hw);
+	u32 val;
+	unsigned long flags = 0;
+
+	if (mux->flags & CLK_MUX_INDEX_BIT)
+		index = (1 << ffs(index));
+
+	if (mux->flags & CLK_MUX_INDEX_ONE)
+		index++;
+
+	if (mux->lock)
+		spin_lock_irqsave(mux->lock, flags);
+
+	val = readl(mux->reg);
+	val &= ~(((1 << mux->width) - 1) << mux->shift);
+	val |= index << mux->shift;
+	writel(val, mux->reg);
+
+	if (mux->lock)
+		spin_unlock_irqrestore(mux->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_mux_set_parent);
+
+struct clk_ops clk_mux_ops = {
+	.get_parent = clk_mux_get_parent,
+	.set_parent = clk_mux_set_parent,
+};
+EXPORT_SYMBOL_GPL(clk_mux_ops);
+
+struct clk *clk_register_mux(struct device *dev, const char *name,
+		char **parent_names, u8 num_parents, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_mux_flags, spinlock_t *lock)
+{
+	struct clk_mux *mux;
+
+	mux = kmalloc(sizeof(struct clk_mux), GFP_KERNEL);
+
+	if (!mux) {
+		pr_err("%s: could not allocate mux clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* struct clk_mux assignments */
+	mux->reg = reg;
+	mux->shift = shift;
+	mux->width = width;
+	mux->flags = clk_mux_flags;
+	mux->lock = lock;
+
+	return clk_register(dev, name, &clk_mux_ops, &mux->hw,
+			parent_names, num_parents, flags);
+}
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
new file mode 100644
index 00000000000..9cf6f59e3e1
--- /dev/null
+++ b/drivers/clk/clk.c
@@ -0,0 +1,1461 @@
+/*
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
+ *
+ * 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.
+ *
+ * Standard functionality for the common clock API.  See Documentation/clk.txt
+ */
+
+#include <linux/clk-private.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+static DEFINE_SPINLOCK(enable_lock);
+static DEFINE_MUTEX(prepare_lock);
+
+static HLIST_HEAD(clk_root_list);
+static HLIST_HEAD(clk_orphan_list);
+static LIST_HEAD(clk_notifier_list);
+
+/***        debugfs support        ***/
+
+#ifdef CONFIG_COMMON_CLK_DEBUG
+#include <linux/debugfs.h>
+
+static struct dentry *rootdir;
+static struct dentry *orphandir;
+static int inited = 0;
+
+/* caller must hold prepare_lock */
+static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
+{
+	struct dentry *d;
+	int ret = -ENOMEM;
+
+	if (!clk || !pdentry) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	d = debugfs_create_dir(clk->name, pdentry);
+	if (!d)
+		goto out;
+
+	clk->dentry = d;
+
+	d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
+			(u32 *)&clk->rate);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
+			(u32 *)&clk->flags);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
+			(u32 *)&clk->prepare_count);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
+			(u32 *)&clk->enable_count);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
+			(u32 *)&clk->notifier_count);
+	if (!d)
+		goto err_out;
+
+	ret = 0;
+	goto out;
+
+err_out:
+	debugfs_remove(clk->dentry);
+out:
+	return ret;
+}
+
+/* caller must hold prepare_lock */
+static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
+{
+	struct clk *child;
+	struct hlist_node *tmp;
+	int ret = -EINVAL;;
+
+	if (!clk || !pdentry)
+		goto out;
+
+	ret = clk_debug_create_one(clk, pdentry);
+
+	if (ret)
+		goto out;
+
+	hlist_for_each_entry(child, tmp, &clk->children, child_node)
+		clk_debug_create_subtree(child, clk->dentry);
+
+	ret = 0;
+out:
+	return ret;
+}
+
+/**
+ * clk_debug_register - add a clk node to the debugfs clk tree
+ * @clk: the clk being added to the debugfs clk tree
+ *
+ * Dynamically adds a clk to the debugfs clk tree if debugfs has been
+ * initialized.  Otherwise it bails out early since the debugfs clk tree
+ * will be created lazily by clk_debug_init as part of a late_initcall.
+ *
+ * Caller must hold prepare_lock.  Only clk_init calls this function (so
+ * far) so this is taken care.
+ */
+static int clk_debug_register(struct clk *clk)
+{
+	struct clk *parent;
+	struct dentry *pdentry;
+	int ret = 0;
+
+	if (!inited)
+		goto out;
+
+	parent = clk->parent;
+
+	/*
+	 * Check to see if a clk is a root clk.  Also check that it is
+	 * safe to add this clk to debugfs
+	 */
+	if (!parent)
+		if (clk->flags & CLK_IS_ROOT)
+			pdentry = rootdir;
+		else
+			pdentry = orphandir;
+	else
+		if (parent->dentry)
+			pdentry = parent->dentry;
+		else
+			goto out;
+
+	ret = clk_debug_create_subtree(clk, pdentry);
+
+out:
+	return ret;
+}
+
+/**
+ * clk_debug_init - lazily create the debugfs clk tree visualization
+ *
+ * clks are often initialized very early during boot before memory can
+ * be dynamically allocated and well before debugfs is setup.
+ * clk_debug_init walks the clk tree hierarchy while holding
+ * prepare_lock and creates the topology as part of a late_initcall,
+ * thus insuring that clks initialized very early will still be
+ * represented in the debugfs clk tree.  This function should only be
+ * called once at boot-time, and all other clks added dynamically will
+ * be done so with clk_debug_register.
+ */
+static int __init clk_debug_init(void)
+{
+	struct clk *clk;
+	struct hlist_node *tmp;
+
+	rootdir = debugfs_create_dir("clk", NULL);
+
+	if (!rootdir)
+		return -ENOMEM;
+
+	orphandir = debugfs_create_dir("orphans", rootdir);
+
+	if (!orphandir)
+		return -ENOMEM;
+
+	mutex_lock(&prepare_lock);
+
+	hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
+		clk_debug_create_subtree(clk, rootdir);
+
+	hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
+		clk_debug_create_subtree(clk, orphandir);
+
+	inited = 1;
+
+	mutex_unlock(&prepare_lock);
+
+	return 0;
+}
+late_initcall(clk_debug_init);
+#else
+static inline int clk_debug_register(struct clk *clk) { return 0; }
+#endif /* CONFIG_COMMON_CLK_DEBUG */
+
+#ifdef CONFIG_COMMON_CLK_DISABLE_UNUSED
+/* caller must hold prepare_lock */
+static void clk_disable_unused_subtree(struct clk *clk)
+{
+	struct clk *child;
+	struct hlist_node *tmp;
+	unsigned long flags;
+
+	if (!clk)
+		goto out;
+
+	hlist_for_each_entry(child, tmp, &clk->children, child_node)
+		clk_disable_unused_subtree(child);
+
+	spin_lock_irqsave(&enable_lock, flags);
+
+	if (clk->enable_count)
+		goto unlock_out;
+
+	if (clk->flags & CLK_IGNORE_UNUSED)
+		goto unlock_out;
+
+	if (__clk_is_enabled(clk) && clk->ops->disable)
+		clk->ops->disable(clk->hw);
+
+unlock_out:
+	spin_unlock_irqrestore(&enable_lock, flags);
+
+out:
+	return;
+}
+
+static int clk_disable_unused(void)
+{
+	struct clk *clk;
+	struct hlist_node *tmp;
+
+	mutex_lock(&prepare_lock);
+
+	hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
+		clk_disable_unused_subtree(clk);
+
+	hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
+		clk_disable_unused_subtree(clk);
+
+	mutex_unlock(&prepare_lock);
+
+	return 0;
+}
+late_initcall(clk_disable_unused);
+#else
+static inline int clk_disable_unused(struct clk *clk) { return 0; }
+#endif /* CONFIG_COMMON_CLK_DISABLE_UNUSED */
+
+/***    helper functions   ***/
+
+inline const char *__clk_get_name(struct clk *clk)
+{
+	return !clk ? NULL : clk->name;
+}
+
+inline struct clk_hw *__clk_get_hw(struct clk *clk)
+{
+	return !clk ? NULL : clk->hw;
+}
+
+inline u8 __clk_get_num_parents(struct clk *clk)
+{
+	return !clk ? -EINVAL : clk->num_parents;
+}
+
+inline struct clk *__clk_get_parent(struct clk *clk)
+{
+	return !clk ? NULL : clk->parent;
+}
+
+inline int __clk_get_enable_count(struct clk *clk)
+{
+	return !clk ? -EINVAL : clk->enable_count;
+}
+
+inline int __clk_get_prepare_count(struct clk *clk)
+{
+	return !clk ? -EINVAL : clk->prepare_count;
+}
+
+unsigned long __clk_get_rate(struct clk *clk)
+{
+	unsigned long ret;
+
+	if (!clk) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = clk->rate;
+
+	if (clk->flags & CLK_IS_ROOT)
+		goto out;
+
+	if (!clk->parent)
+		ret = -ENODEV;
+
+out:
+	return ret;
+}
+
+inline unsigned long __clk_get_flags(struct clk *clk)
+{
+	return !clk ? -EINVAL : clk->flags;
+}
+
+int __clk_is_enabled(struct clk *clk)
+{
+	int ret;
+
+	if (!clk)
+		return -EINVAL;
+
+	/*
+	 * .is_enabled is only mandatory for clocks that gate
+	 * fall back to software usage counter if .is_enabled is missing
+	 */
+	if (!clk->ops->is_enabled) {
+		ret = clk->enable_count ? 1 : 0;
+		goto out;
+	}
+
+	ret = clk->ops->is_enabled(clk->hw);
+out:
+	return ret;
+}
+
+static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
+{
+	struct clk *child;
+	struct clk *ret;
+	struct hlist_node *tmp;
+
+	if (!strcmp(clk->name, name))
+		return clk;
+
+	hlist_for_each_entry(child, tmp, &clk->children, child_node) {
+		ret = __clk_lookup_subtree(name, child);
+		if (ret)
+			return ret;
+	}
+
+	return NULL;
+}
+
+struct clk *__clk_lookup(const char *name)
+{
+	struct clk *root_clk;
+	struct clk *ret;
+	struct hlist_node *tmp;
+
+	if (!name)
+		return NULL;
+
+	/* search the 'proper' clk tree first */
+	hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) {
+		ret = __clk_lookup_subtree(name, root_clk);
+		if (ret)
+			return ret;
+	}
+
+	/* if not found, then search the orphan tree */
+	hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) {
+		ret = __clk_lookup_subtree(name, root_clk);
+		if (ret)
+			return ret;
+	}
+
+	return NULL;
+}
+
+/***        clk api        ***/
+
+void __clk_unprepare(struct clk *clk)
+{
+	if (!clk)
+		return;
+
+	if (WARN_ON(clk->prepare_count == 0))
+		return;
+
+	if (--clk->prepare_count > 0)
+		return;
+
+	WARN_ON(clk->enable_count > 0);
+
+	if (clk->ops->unprepare)
+		clk->ops->unprepare(clk->hw);
+
+	__clk_unprepare(clk->parent);
+}
+
+/**
+ * clk_unprepare - undo preparation of a clock source
+ * @clk: the clk being unprepare
+ *
+ * clk_unprepare may sleep, which differentiates it from clk_disable.  In a
+ * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
+ * if the operation may sleep.  One example is a clk which is accessed over
+ * I2c.  In the complex case a clk gate operation may require a fast and a slow
+ * part.  It is this reason that clk_unprepare and clk_disable are not mutually
+ * exclusive.  In fact clk_disable must be called before clk_unprepare.
+ */
+void clk_unprepare(struct clk *clk)
+{
+	mutex_lock(&prepare_lock);
+	__clk_unprepare(clk);
+	mutex_unlock(&prepare_lock);
+}
+EXPORT_SYMBOL_GPL(clk_unprepare);
+
+int __clk_prepare(struct clk *clk)
+{
+	int ret = 0;
+
+	if (!clk)
+		return 0;
+
+	if (clk->prepare_count == 0) {
+		ret = __clk_prepare(clk->parent);
+		if (ret)
+			return ret;
+
+		if (clk->ops->prepare) {
+			ret = clk->ops->prepare(clk->hw);
+			if (ret) {
+				__clk_unprepare(clk->parent);
+				return ret;
+			}
+		}
+	}
+
+	clk->prepare_count++;
+
+	return 0;
+}
+
+/**
+ * clk_prepare - prepare a clock source
+ * @clk: the clk being prepared
+ *
+ * clk_prepare may sleep, which differentiates it from clk_enable.  In a simple
+ * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
+ * operation may sleep.  One example is a clk which is accessed over I2c.  In
+ * the complex case a clk ungate operation may require a fast and a slow part.
+ * It is this reason that clk_prepare and clk_enable are not mutually
+ * exclusive.  In fact clk_prepare must be called before clk_enable.
+ * Returns 0 on success, -EERROR otherwise.
+ */
+int clk_prepare(struct clk *clk)
+{
+	int ret;
+
+	mutex_lock(&prepare_lock);
+	ret = __clk_prepare(clk);
+	mutex_unlock(&prepare_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_prepare);
+
+static void __clk_disable(struct clk *clk)
+{
+	if (!clk)
+		return;
+
+	if (WARN_ON(clk->enable_count == 0))
+		return;
+
+	if (--clk->enable_count > 0)
+		return;
+
+	if (clk->ops->disable)
+		clk->ops->disable(clk->hw);
+
+	__clk_disable(clk->parent);
+}
+
+/**
+ * clk_disable - gate a clock
+ * @clk: the clk being gated
+ *
+ * clk_disable must not sleep, which differentiates it from clk_unprepare.  In
+ * a simple case, clk_disable can be used instead of clk_unprepare to gate a
+ * clk if the operation is fast and will never sleep.  One example is a
+ * SoC-internal clk which is controlled via simple register writes.  In the
+ * complex case a clk gate operation may require a fast and a slow part.  It is
+ * this reason that clk_unprepare and clk_disable are not mutually exclusive.
+ * In fact clk_disable must be called before clk_unprepare.
+ */
+void clk_disable(struct clk *clk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&enable_lock, flags);
+	__clk_disable(clk);
+	spin_unlock_irqrestore(&enable_lock, flags);
+}
+EXPORT_SYMBOL_GPL(clk_disable);
+
+static int __clk_enable(struct clk *clk)
+{
+	int ret = 0;
+
+	if (!clk)
+		return 0;
+
+	if (WARN_ON(clk->prepare_count == 0))
+		return -ESHUTDOWN;
+
+	if (clk->enable_count == 0) {
+		ret = __clk_enable(clk->parent);
+
+		if (ret)
+			return ret;
+
+		if (clk->ops->enable) {
+			ret = clk->ops->enable(clk->hw);
+			if (ret) {
+				__clk_disable(clk->parent);
+				return ret;
+			}
+		}
+	}
+
+	clk->enable_count++;
+	return 0;