[ARM] tegra: Add clock support

v2: fixes from Russell King:
	- include linux/io.h instead of asm/io.h
	- fix whitespace in Kconfig
	- Use spin_lock_init to initialize lock
	- Return -ENOSYS instead of BUG for unimplemented clock ops
	- Use proper return values in tegra2 clock ops
    additional changes:
	- Rename some clocks to match dev_ids
	- add rate propagation
	- add debugfs entries
	- add support for clock listed in clk_lookup under multiple dev_ids
v3:
	- Replace per-clock locking with global clock lock
	- Autodetect clock state on init
	- Let clock dividers pick next lower possible frequency
	- Add support for clock init tables
	- Minor bug fixes
	- Fix checkpatch issues

Signed-off-by: Colin Cross <ccross@android.com>

8 files changed, 2072 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 56d2c4291e43..43aad7a0207a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -568,6 +568,7 @@ config ARCH_TEGRA
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_GPIO
 	select HAVE_CLK
+	select COMMON_CLKDEV
 	select ARCH_HAS_BARRIERS if CACHE_L2X0
 	help
 	  This enables support for NVIDIA Tegra based systems (Tegra APX,
diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index a0d2c5ba6cd4..e20546ab2f5f 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -1,3 +1,5 @@
 obj-y                                   += common.o
 obj-y                                   += io.o
 obj-y                                   += irq.o
+obj-y                                   += clock.o
+obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += tegra2_clocks.o
diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
new file mode 100644
index 000000000000..03ad578349b9
--- /dev/null
+++ b/arch/arm/mach-tegra/clock.c
@@ -0,0 +1,488 @@
+/*
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <asm/clkdev.h>
+
+#include "clock.h"
+
+static LIST_HEAD(clocks);
+
+static DEFINE_SPINLOCK(clock_lock);
+
+struct clk *tegra_get_clock_by_name(const char *name)
+{
+	struct clk *c;
+	struct clk *ret = NULL;
+	unsigned long flags;
+	spin_lock_irqsave(&clock_lock, flags);
+	list_for_each_entry(c, &clocks, node) {
+		if (strcmp(c->name, name) == 0) {
+			ret = c;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&clock_lock, flags);
+	return ret;
+}
+
+int clk_reparent(struct clk *c, struct clk *parent)
+{
+	pr_debug("%s: %s\n", __func__, c->name);
+	if (c->refcnt && c->parent)
+		clk_disable_locked(c->parent);
+	c->parent = parent;
+	if (c->refcnt && c->parent)
+		clk_enable_locked(c->parent);
+	list_del(&c->sibling);
+	list_add_tail(&c->sibling, &parent->children);
+	return 0;
+}
+
+static void propagate_rate(struct clk *c)
+{
+	struct clk *clkp;
+	pr_debug("%s: %s\n", __func__, c->name);
+	list_for_each_entry(clkp, &c->children, sibling) {
+		pr_debug("   %s\n", clkp->name);
+		if (clkp->ops->recalculate_rate)
+			clkp->ops->recalculate_rate(clkp);
+		propagate_rate(clkp);
+	}
+}
+
+void clk_init(struct clk *c)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&clock_lock, flags);
+
+	INIT_LIST_HEAD(&c->children);
+	INIT_LIST_HEAD(&c->sibling);
+
+	if (c->ops && c->ops->init)
+		c->ops->init(c);
+
+	list_add(&c->node, &clocks);
+
+	if (c->parent)
+		list_add_tail(&c->sibling, &c->parent->children);
+
+	spin_unlock_irqrestore(&clock_lock, flags);
+}
+
+int clk_enable_locked(struct clk *c)
+{
+	int ret;
+	pr_debug("%s: %s\n", __func__, c->name);
+	if (c->refcnt == 0) {
+		if (c->parent) {
+			ret = clk_enable_locked(c->parent);
+			if (ret)
+				return ret;
+		}
+
+		if (c->ops && c->ops->enable) {
+			ret = c->ops->enable(c);
+			if (ret) {
+				if (c->parent)
+					clk_disable_locked(c->parent);
+				return ret;
+			}
+			c->state = ON;
+#ifdef CONFIG_DEBUG_FS
+			c->set = 1;
+#endif
+		}
+	}
+	c->refcnt++;
+
+	return 0;
+}
+
+int clk_enable(struct clk *c)
+{
+	int ret;
+	unsigned long flags;
+	spin_lock_irqsave(&clock_lock, flags);
+	ret = clk_enable_locked(c);
+	spin_unlock_irqrestore(&clock_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(clk_enable);
+
+void clk_disable_locked(struct clk *c)
+{
+	pr_debug("%s: %s\n", __func__, c->name);
+	if (c->refcnt == 0) {
+		WARN(1, "Attempting to disable clock %s with refcnt 0", c->name);
+		return;
+	}
+	if (c->refcnt == 1) {
+		if (c->ops && c->ops->disable)
+			c->ops->disable(c);
+
+		if (c->parent)
+			clk_disable_locked(c->parent);
+
+		c->state = OFF;
+	}
+	c->refcnt--;
+}
+
+void clk_disable(struct clk *c)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&clock_lock, flags);
+	clk_disable_locked(c);
+	spin_unlock_irqrestore(&clock_lock, flags);
+}
+EXPORT_SYMBOL(clk_disable);
+
+int clk_set_parent_locked(struct clk *c, struct clk *parent)
+{
+	int ret;
+
+	pr_debug("%s: %s\n", __func__, c->name);
+
+	if (!c->ops || !c->ops->set_parent)
+		return -ENOSYS;
+
+	ret = c->ops->set_parent(c, parent);
+
+	if (ret)
+		return ret;
+
+	propagate_rate(c);
+
+	return 0;
+}
+
+int clk_set_parent(struct clk *c, struct clk *parent)
+{
+	int ret;
+	unsigned long flags;
+	spin_lock_irqsave(&clock_lock, flags);
+	ret = clk_set_parent_locked(c, parent);
+	spin_unlock_irqrestore(&clock_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(clk_set_parent);
+
+struct clk *clk_get_parent(struct clk *c)
+{
+	return c->parent;
+}
+EXPORT_SYMBOL(clk_get_parent);
+
+int clk_set_rate(struct clk *c, unsigned long rate)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&clock_lock, flags);
+
+	pr_debug("%s: %s\n", __func__, c->name);
+
+	if (c->ops && c->ops->set_rate)
+		ret = c->ops->set_rate(c, rate);
+	else
+		ret = -ENOSYS;
+
+	propagate_rate(c);
+
+	spin_unlock_irqrestore(&clock_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(clk_set_rate);
+
+unsigned long clk_get_rate(struct clk *c)
+{
+	unsigned long flags;
+	unsigned long ret;
+
+	spin_lock_irqsave(&clock_lock, flags);
+
+	pr_debug("%s: %s\n", __func__, c->name);
+
+	ret = c->rate;
+
+	spin_unlock_irqrestore(&clock_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+static int tegra_clk_init_one_from_table(struct tegra_clk_init_table *table)
+{
+	struct clk *c;
+	struct clk *p;
+
+	int ret = 0;
+
+	c = tegra_get_clock_by_name(table->name);
+
+	if (!c) {
+		pr_warning("Unable to initialize clock %s\n",
+			table->name);
+		return -ENODEV;
+	}
+
+	if (table->parent) {
+		p = tegra_get_clock_by_name(table->parent);
+		if (!p) {
+			pr_warning("Unable to find parent %s of clock %s\n",
+				table->parent, table->name);
+			return -ENODEV;
+		}
+
+		if (c->parent != p) {
+			ret = clk_set_parent(c, p);
+			if (ret) {
+				pr_warning("Unable to set parent %s of clock %s: %d\n",
+					table->parent, table->name, ret);
+				return -EINVAL;
+			}
+		}
+	}
+
+	if (table->rate && table->rate != clk_get_rate(c)) {
+		ret = clk_set_rate(c, table->rate);
+		if (ret) {
+			pr_warning("Unable to set clock %s to rate %lu: %d\n",
+				table->name, table->rate, ret);
+			return -EINVAL;
+		}
+	}
+
+	if (table->enabled) {
+		ret = clk_enable(c);
+		if (ret) {
+			pr_warning("Unable to enable clock %s: %d\n",
+				table->name, ret);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+void tegra_clk_init_from_table(struct tegra_clk_init_table *table)
+{
+	for (; table->name; table++)
+		tegra_clk_init_one_from_table(table);
+}
+EXPORT_SYMBOL(tegra_clk_init_from_table);
+
+void tegra_periph_reset_deassert(struct clk *c)
+{
+	tegra2_periph_reset_deassert(c);
+}
+EXPORT_SYMBOL(tegra_periph_reset_deassert);
+
+void tegra_periph_reset_assert(struct clk *c)
+{
+	tegra2_periph_reset_assert(c);
+}
+EXPORT_SYMBOL(tegra_periph_reset_assert);
+
+int __init tegra_init_clock(void)
+{
+	tegra2_init_clocks();
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *clk_debugfs_root;
+
+
+static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
+{
+	struct clk *child;
+	struct clk *safe;
+	const char *state = "uninit";
+	char div[5] = {0};
+
+	if (c->state == ON)
+		state = "on";
+	else if (c->state == OFF)
+		state = "off";
+
+	if (c->mul != 0 && c->div != 0) {
+		BUG_ON(c->mul > 2);
+		if (c->mul > c->div)
+			snprintf(div, sizeof(div), "x%d", c->mul / c->div);
+		else
+			snprintf(div, sizeof(div), "%d%s", c->div / c->mul,
+				(c->div % c->mul) ? ".5" : "");
+	}
+
+	seq_printf(s, "%*s%-*s %-6s %-3d %-5s %-10lu\n",
+		level * 3 + 1, c->set ? "" : "*",
+		30 - level * 3, c->name,
+		state, c->refcnt, div, c->rate);
+	list_for_each_entry_safe(child, safe, &c->children, sibling) {
+		clock_tree_show_one(s, child, level + 1);
+	}
+}
+
+static int clock_tree_show(struct seq_file *s, void *data)
+{
+	struct clk *c;
+	unsigned long flags;
+	seq_printf(s, " clock                          state  ref div   rate      \n");
+	seq_printf(s, "-----------------------------------------------------------\n");
+	spin_lock_irqsave(&clock_lock, flags);
+	list_for_each_entry(c, &clocks, node)
+		if (c->parent == NULL)
+			clock_tree_show_one(s, c, 0);
+	spin_unlock_irqrestore(&clock_lock, flags);
+	return 0;
+}
+
+static int clock_tree_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, clock_tree_show, inode->i_private);
+}
+
+static const struct file_operations clock_tree_fops = {
+	.open		= clock_tree_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int possible_parents_show(struct seq_file *s, void *data)
+{
+	struct clk *c = s->private;
+	int i;
+
+	for (i = 0; c->inputs[i].input; i++) {
+		char *first = (i == 0) ? "" : " ";
+		seq_printf(s, "%s%s", first, c->inputs[i].input->name);
+	}
+	seq_printf(s, "\n");
+	return 0;
+}
+
+static int possible_parents_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, possible_parents_show, inode->i_private);
+}
+
+static const struct file_operations possible_parents_fops = {
+	.open		= possible_parents_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int clk_debugfs_register_one(struct clk *c)
+{
+	struct dentry *d, *child, *child_tmp;
+
+	d = debugfs_create_dir(c->name, clk_debugfs_root);
+	if (!d)
+		return -ENOMEM;
+	c->dent = d;
+
+	d = debugfs_create_u8("refcnt", S_IRUGO, c->dent, (u8 *)&c->refcnt);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
+	if (!d)
+		goto err_out;
+
+	d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
+	if (!d)
+		goto err_out;
+
+	if (c->inputs) {
+		d = debugfs_create_file("possible_parents", S_IRUGO, c->dent,
+			c, &possible_parents_fops);
+		if (!d)
+			goto err_out;
+	}
+
+	return 0;
+
+err_out:
+	d = c->dent;
+	list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
+		debugfs_remove(child);
+	debugfs_remove(c->dent);
+	return -ENOMEM;
+}
+
+static int clk_debugfs_register(struct clk *c)
+{
+	int err;
+	struct clk *pa = c->parent;
+
+	if (pa && !pa->dent) {
+		err = clk_debugfs_register(pa);
+		if (err)
+			return err;
+	}
+
+	if (!c->dent) {
+		err = clk_debugfs_register_one(c);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int __init clk_debugfs_init(void)
+{
+	struct clk *c;
+	struct dentry *d;
+	int err = -ENOMEM;
+
+	d = debugfs_create_dir("clock", NULL);
+	if (!d)
+		return -ENOMEM;
+	clk_debugfs_root = d;
+
+	d = debugfs_create_file("clock_tree", S_IRUGO, clk_debugfs_root, NULL,
+		&clock_tree_fops);
+	if (!d)
+		goto err_out;
+
+	list_for_each_entry(c, &clocks, node) {
+		err = clk_debugfs_register(c);
+		if (err)
+			goto err_out;
+	}
+	return 0;
+err_out:
+	debugfs_remove_recursive(clk_debugfs_root);
+	return err;
+}
+
+late_initcall(clk_debugfs_init);
+#endif
diff --git a/arch/arm/mach-tegra/clock.h b/arch/arm/mach-tegra/clock.h
new file mode 100644
index 000000000000..af7c70e2a3ba
--- /dev/null
+++ b/arch/arm/mach-tegra/clock.h
@@ -0,0 +1,147 @@
+/*
+ * arch/arm/mach-tegra/include/mach/clock.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 __MACH_TEGRA_CLOCK_H
+#define __MACH_TEGRA_CLOCK_H
+
+#include <linux/list.h>
+#include <asm/clkdev.h>
+
+#define DIV_BUS			(1 << 0)
+#define DIV_U71			(1 << 1)
+#define DIV_U71_FIXED		(1 << 2)
+#define DIV_2			(1 << 3)
+#define PLL_FIXED		(1 << 4)
+#define PLL_HAS_CPCON		(1 << 5)
+#define MUX			(1 << 6)
+#define PLLD			(1 << 7)
+#define PERIPH_NO_RESET		(1 << 8)
+#define PERIPH_NO_ENB		(1 << 9)
+#define PERIPH_EMC_ENB		(1 << 10)
+#define PERIPH_MANUAL_RESET	(1 << 11)
+#define PLL_ALT_MISC_REG	(1 << 12)
+#define ENABLE_ON_INIT		(1 << 28)
+
+struct clk;
+
+struct clk_mux_sel {
+	struct clk	*input;
+	u32		value;
+};
+
+struct clk_pll_table {
+	unsigned long	input_rate;
+	unsigned long	output_rate;
+	u16		n;
+	u16		m;
+	u8		p;
+	u8		cpcon;
+};
+
+struct clk_ops {
+	void		(*init)(struct clk *);
+	int		(*enable)(struct clk *);
+	void		(*disable)(struct clk *);
+	void		(*recalc)(struct clk *);
+	int		(*set_parent)(struct clk *, struct clk *);
+	int		(*set_rate)(struct clk *, unsigned long);
+	unsigned long	(*get_rate)(struct clk *);
+	long		(*round_rate)(struct clk *, unsigned long);
+	unsigned long	(*recalculate_rate)(struct clk *);
+};
+
+enum clk_state {
+	UNINITIALIZED = 0,
+	ON,
+	OFF,
+};
+
+struct clk {
+	/* node for master clocks list */
+	struct list_head		node;
+	struct list_head		children;	/* list of children */
+	struct list_head		sibling;	/* node for children */
+#ifdef CONFIG_DEBUG_FS
+	struct dentry			*dent;
+	struct dentry			*parent_dent;
+#endif
+	struct clk_ops			*ops;
+	struct clk			*parent;
+	struct clk_lookup		lookup;
+	unsigned long			rate;
+	u32				flags;
+	u32				refcnt;
+	const char			*name;
+	u32				reg;
+	u32				reg_shift;
+	unsigned int			clk_num;
+	enum clk_state			state;
+#ifdef CONFIG_DEBUG_FS
+	bool				set;
+#endif
+
+	/* PLL */
+	unsigned long			input_min;
+	unsigned long			input_max;
+	unsigned long			cf_min;
+	unsigned long			cf_max;
+	unsigned long			vco_min;
+	unsigned long			vco_max;
+	u32				m;
+	u32				n;
+	u32				p;
+	u32				cpcon;
+	const struct clk_pll_table	*pll_table;
+
+	/* DIV */
+	u32				div;
+	u32				mul;
+
+	/* MUX */
+	const struct clk_mux_sel	*inputs;
+	u32				sel;
+	u32				reg_mask;
+};
+
+
+struct clk_duplicate {
+	const char *name;
+	struct clk_lookup lookup;
+};
+
+struct tegra_clk_init_table {
+	const char *name;
+	const char *parent;
+	unsigned long rate;
+	bool enabled;
+};
+
+void tegra2_init_clocks(void);
+void tegra2_periph_reset_deassert(struct clk *c);
+void tegra2_periph_reset_assert(struct clk *c);
+void clk_init(struct clk *clk);
+struct clk *tegra_get_clock_by_name(const char *name);
+unsigned long clk_measure_input_freq(void);
+void clk_disable_locked(struct clk *c);
+int clk_enable_locked(struct clk *c);
+int clk_set_parent_locked(struct clk *c, struct clk *parent);
+int clk_reparent(struct clk *c, struct clk *parent);
+void tegra_clk_init_from_table(struct tegra_clk_init_table *table);
+
+#endif
diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
index 20875ee8f039..039a514b61ef 100644
--- a/arch/arm/mach-tegra/common.c
+++ b/arch/arm/mach-tegra/common.c
@@ -25,6 +25,21 @@
 #include <mach/iomap.h>
 
 #include "board.h"
+#include "clock.h"
+
+static __initdata struct tegra_clk_init_table common_clk_init_table[] = {
+	/* name		parent		rate		enabled */
+	{ "clk_m",	NULL,		0,		true },
+	{ "pll_p",	"clk_m",	216000000,	true },
+	{ "pll_p_out1",	"pll_p",	28800000,	true },
+	{ "pll_p_out2",	"pll_p",	48000000,	true },
+	{ "pll_p_out3",	"pll_p",	72000000,	true },
+	{ "pll_p_out4",	"pll_p",	108000000,	true },
+	{ "sys",	"pll_p_out4",	108000000,	true },
+	{ "hclk",	"sys",		108000000,	true },
+	{ "pclk",	"hclk",		54000000,	true },
+	{ NULL,		NULL,		0,		0},
+};
 
 void __init tegra_init_cache(void)
 {
@@ -40,5 +55,7 @@ void __init tegra_init_cache(void)
 
 void __init tegra_common_init(void)
 {
+	tegra_init_clock();
+	tegra_clk_init_from_table(common_clk_init_table);
 	tegra_init_cache();
 }
diff --git a/arch/arm/mach-tegra/include/mach/clk.h b/arch/arm/mach-tegra/include/mach/clk.h
new file mode 100644
index 000000000000..2896f25ebfb5
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/clk.h
@@ -0,0 +1,26 @@
+/*
+ * arch/arm/mach-tegra/include/mach/clk.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Erik Gilling <konkers@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 __MACH_CLK_H
+#define __MACH_CLK_H
+
+void tegra_periph_reset_deassert(struct clk *c);
+void tegra_periph_reset_assert(struct clk *c);
+
+#endif
diff --git a/arch/arm/mach-tegra/include/mach/clkdev.h b/arch/arm/mach-tegra/include/mach/clkdev.h
new file mode 100644
index 000000000000..412f5c63e65a
--- /dev/null
+++ b/arch/arm/mach-tegra/include/mach/clkdev.h
@@ -0,0 +1,32 @@
+/*
+ * arch/arm/mach-tegra/include/mach/clkdev.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 __MACH_CLKDEV_H
+#define __MACH_CLKDEV_H
+
+static inline int __clk_get(struct clk *clk)
+{
+	return 1;
+}
+
+static inline void __clk_put(struct clk *clk)
+{
+}
+
+#endif
diff --git a/arch/arm/mach-tegra/tegra2_clocks.c b/arch/arm/mach-tegra/tegra2_clocks.c
new file mode 100644
index 000000000000..426163231fff
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra2_clocks.c
@@ -0,0 +1,1359 @@
+/*
+ * arch/arm/mach-tegra/tegra2_clocks.c
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/hrtimer.h>
+
+#include <asm/clkdev.h>
+
+#include <mach/iomap.h>
+
+#include "clock.h"
+
+#define RST_DEVICES			0x004
+#define RST_DEVICES_SET			0x300
+#define RST_DEVICES_CLR			0x304
+
+#define CLK_OUT_ENB			0x010
+#define CLK_OUT_ENB_SET			0x320
+#define CLK_OUT_ENB_CLR			0x324
+
+#define OSC_CTRL			0x50
+#define OSC_CTRL_OSC_FREQ_MASK		(3<<30)
+#define OSC_CTRL_OSC_FREQ_13MHZ		(0<<30)
+#define OSC_CTRL_OSC_FREQ_19_2MHZ	(1<<30)
+#define OSC_CTRL_OSC_FREQ_12MHZ		(2<<30)
+#define OSC_CTRL_OSC_FREQ_26MHZ		(3<<30)
+
+#define OSC_FREQ_DET			0x58
+#define OSC_FREQ_DET_TRIG		(1<<31)
+
+#define OSC_FREQ_DET_STATUS		0x5C
+#define OSC_FREQ_DET_BUSY		(1<<31)
+#define OSC_FREQ_DET_CNT_MASK		0xFFFF
+
+#define PERIPH_CLK_SOURCE_MASK		(3<<30)
+#define PERIPH_CLK_SOURCE_SHIFT		30
+#define PERIPH_CLK_SOURCE_ENABLE	(1<<28)
+#define PERIPH_CLK_SOURCE_DIV_MASK	0xFF
+#define PERIPH_CLK_SOURCE_DIV_SHIFT	0
+
+#define PLL_BASE			0x0
+#define PLL_BASE_BYPASS			(1<<31)
+#define PLL_BASE_ENABLE			(1<<30)
+#define PLL_BASE_REF_ENABLE		(1<<29)
+#define PLL_BASE_OVERRIDE		(1<<28)
+#define PLL_BASE_LOCK			(1<<27)
+#define PLL_BASE_DIVP_MASK		(0x7<<20)
+#define PLL_BASE_DIVP_SHIFT		20
+#define PLL_BASE_DIVN_MASK		(0x3FF<<8)
+#define PLL_BASE_DIVN_SHIFT		8
+#define PLL_BASE_DIVM_MASK		(0x1F)
+#define PLL_BASE_DIVM_SHIFT		0
+
+#define PLL_OUT_RATIO_MASK		(0xFF<<8)
+#define PLL_OUT_RATIO_SHIFT		8
+#define PLL_OUT_OVERRIDE		(1<<2)
+#define PLL_OUT_CLKEN			(1<<1)
+#define PLL_OUT_RESET_DISABLE		(1<<0)
+
+#define PLL_MISC(c)			(((c)->flags & PLL_ALT_MISC_REG) ? 0x4 : 0xc)
+#define PLL_MISC_DCCON_SHIFT		20
+#define PLL_MISC_LOCK_ENABLE		(1<<18)
+#define PLL_MISC_CPCON_SHIFT		8
+#define PLL_MISC_CPCON_MASK		(0xF<<PLL_MISC_CPCON_SHIFT)
+#define PLL_MISC_LFCON_SHIFT		4
+#define PLL_MISC_LFCON_MASK		(0xF<<PLL_MISC_LFCON_SHIFT)
+#define PLL_MISC_VCOCON_SHIFT		0
+#define PLL_MISC_VCOCON_MASK		(0xF<<PLL_MISC_VCOCON_SHIFT)
+
+#define PLLD_MISC_CLKENABLE		(1<<30)
+#define PLLD_MISC_DIV_RST		(1<<23)
+#define PLLD_MISC_DCCON_SHIFT		12
+
+#define PERIPH_CLK_TO_ENB_REG(c)	((c->clk_num / 32) * 4)
+#define PERIPH_CLK_TO_ENB_SET_REG(c)	((c->clk_num / 32) * 8)
+#define PERIPH_CLK_TO_ENB_BIT(c)	(1 << (c->clk_num % 32))
+
+#define SUPER_CLK_MUX			0x00
+#define SUPER_STATE_SHIFT		28
+#define SUPER_STATE_MASK		(0xF << SUPER_STATE_SHIFT)
+#define SUPER_STATE_STANDBY		(0x0 << SUPER_STATE_SHIFT)
+#define SUPER_STATE_IDLE		(0x1 << SUPER_STATE_SHIFT)
+#define SUPER_STATE_RUN			(0x2 << SUPER_STATE_SHIFT)
+#define SUPER_STATE_IRQ			(0x3 << SUPER_STATE_SHIFT)
+#define SUPER_STATE_FIQ			(0x4 << SUPER_STATE_SHIFT)
+#define SUPER_SOURCE_MASK		0xF
+#define	SUPER_FIQ_SOURCE_SHIFT		12
+#define	SUPER_IRQ_SOURCE_SHIFT		8
+#define	SUPER_RUN_SOURCE_SHIFT		4
+#define	SUPER_IDLE_SOURCE_SHIFT		0
+
+#define SUPER_CLK_DIVIDER		0x04
+
+#define BUS_CLK_DISABLE			(1<<3)
+#define BUS_CLK_DIV_MASK		0x3
+
+static void __iomem *reg_clk_base = IO_ADDRESS(TEGRA_CLK_RESET_BASE);
+
+#define clk_writel(value, reg) \
+	__raw_writel(value, (u32)reg_clk_base + (reg))
+#define clk_readl(reg) \
+	__raw_readl((u32)reg_clk_base + (reg))
+
+unsigned long clk_measure_input_freq(void)
+{
+	u32 clock_autodetect;
+	clk_writel(OSC_FREQ_DET_TRIG | 1, OSC_FREQ_DET);
+	do {} while (clk_readl(OSC_FREQ_DET_STATUS) & OSC_FREQ_DET_BUSY);
+	clock_autodetect = clk_readl(OSC_FREQ_DET_STATUS);
+	if (clock_autodetect >= 732 - 3 && clock_autodetect <= 732 + 3) {
+		return 12000000;
+	} else if (clock_autodetect >= 794 - 3 && clock_autodetect <= 794 + 3) {
+		return 13000000;
+	} else if (clock_autodetect >= 1172 - 3 && clock_autodetect <= 1172 + 3) {
+		return 19200000;
+	} else if (clock_autodetect >= 1587 - 3 && clock_autodetect <= 1587 + 3) {
+		return 26000000;
+	} else {
+		pr_err("%s: Unexpected clock autodetect value %d", __func__, clock_autodetect);
+		BUG();
+		return 0;
+	}
+}
+
+static int clk_div71_get_divider(struct clk *c, unsigned long rate)
+{
+	unsigned long divider_u71;
+
+	divider_u71 = DIV_ROUND_UP(c->rate * 2, rate);
+
+	if (divider_u71 - 2 > 255 || divider_u71 - 2 < 0)
+		return -EINVAL;
+
+	return divider_u71 - 2;
+}
+
+static unsigned long tegra2_clk_recalculate_rate(struct clk *c)
+{
+	unsigned long rate;
+	rate = c->parent->rate;
+
+	if (c->mul != 0 && c->div != 0)
+		c->rate = rate * c->mul / c->div;
+	else
+		c->rate = rate;
+	return c->rate;
+}
+
+
+/* clk_m functions */
+static unsigned long tegra2_clk_m_autodetect_rate(struct clk *c)
+{
+	u32 auto_clock_control = clk_readl(OSC_CTRL) & ~OSC_CTRL_OSC_FREQ_MASK;
+
+	c->rate = clk_measure_input_freq();
+	switch (c->rate) {
+	case 12000000:
+		auto_clock_control |= OSC_CTRL_OSC_FREQ_12MHZ;
+		break;
+	case 13000000:
+		auto_clock_control |= OSC_CTRL_OSC_FREQ_13MHZ;
+		break;
+	case 19200000:
+		auto_clock_control |= OSC_CTRL_OSC_FREQ_19_2MHZ;
+		break;
+	case 26000000:
+		auto_clock_control |= OSC_CTRL_OSC_FREQ_26MHZ;
+		break;
+	default:
+		pr_err("%s: Unexpected clock rate %ld", __func__, c->rate);
+		BUG();
+	}
+	clk_writel(auto_clock_control, OSC_CTRL);
+	return c->rate;
+}
+
+static void tegra2_clk_m_init(struct clk *c)
+{
+	pr_debug("%s on clock %s\n", __func__, c->name);
+	tegra2_clk_m_autodetect_rate(c);
+}
+
+static int tegra2_clk_m_enable(struct clk *c)
+{
+	pr_debug("%s on clock %s\n", __func__, c->name);
+	return 0;
+}
+
+static void tegra2_clk_m_disable(struct clk *c)
+{
+	pr_debug("%s on clock %s\n", __func__, c->name);
+	BUG();
+}
+
+static struct clk_ops tegra_clk_m_ops = {
+	.init		= tegra2_clk_m_init,
+	.enable		= tegra2_clk_m_enable,
+	.disable	= tegra2_clk_m_disable,
+};
+
+/* super clock functions */
+/* "super clocks" on tegra have two-stage muxes and a clock skipping
+ * super divider.  We will ignore the clock skipping divider, since we
+ * can't lower the voltage when using the clock skip, but we can if we
+ * lower the PLL frequency.
+ */
+static void tegra2_super_clk_init(struct clk *c)
+{
+	u32 val;
+	int source;
+	int shift;
+	const struct clk_mux_sel *sel;
+	val = clk_readl(c->reg + SUPER_CLK_MUX);
+	c->state = ON;
+	BUG_ON(((val & SUPER_STATE_MASK) != SUPER_STATE_RUN) &&
+		((val & SUPER_STATE_MASK) != SUPER_STATE_IDLE));
+	shift = ((val & SUPER_STATE_MASK) == SUPER_STATE_IDLE) ?
+		SUPER_IDLE_SOURCE_SHIFT : SUPER_RUN_SOURCE_SHIFT;
+	source = (val >> shift) & SUPER_SOURCE_MASK;
+	for (sel = c->inputs; sel->input != NULL; sel++) {
+		if (sel->value == source)
+			break;
+	}
+	BUG_ON(sel->input == NULL);
+	c->parent = sel->input;
+	tegra2_clk_recalculate_rate(c);
+}
+
+static int tegra2_super_clk_enable(struct clk *c)
+{
+	clk_writel(0, c->reg + SUPER_CLK_DIVIDER);
+	return 0;
+}
+
+static void tegra2_super_clk_disable(struct clk *c)
+{
+	pr_debug("%s on clock %s\n", __func__, c->name);
+
+	/* oops - don't disable the CPU clock! */
+	BUG();
+}
+
+static int tegra2_super_clk_set_parent(struct clk *c, struct clk *p)
+{
+	u32 val;
+	const struct clk_mux_sel *sel;
+	int shift;
+	val = clk_readl(c->reg + SUPER_CLK_MUX);;
+	BUG_ON(((val & SUPER_STATE_MASK) != SUPER_STATE_RUN) &&
+		((val & SUPER_STATE_MASK) != SUPER_STATE_IDLE));
+	shift = ((val & SUPER_STATE_MASK) == SUPER_STATE_IDLE) ?
+		SUPER_IDLE_SOURCE_SHIFT : SUPER_RUN_SOURCE_SHIFT;
+	for (sel = c->inputs; sel->input != NULL; sel++) {
+		if (sel->input == p) {
+			clk_reparent(c, p);
+			val &= ~(SUPER_SOURCE_MASK << shift);
+			val |= sel->value << shift;
+			clk_writel(val, c->reg);
+			c->rate = c->parent->rate;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static struct clk_ops tegra_super_ops = {
+	.init			= tegra2_super_clk_init,
+	.enable			= tegra2_super_clk_enable,
+	.disable		= tegra2_super_clk_disable,
+	.set_parent		= tegra2_super_clk_set_parent,
+	.recalculate_rate	= tegra2_clk_recalculate_rate,
+};
+
+/* bus clock functions */
+static void tegra2_bus_clk_init(struct clk *c)
+{
+	u32 val = clk_readl(c->reg);
+	c->state = ((val >> c->reg_shift) & BUS_CLK_DISABLE) ? OFF : ON;
+	c->div = ((val >> c->reg_shift) & BUS_CLK_DIV_MASK) + 1;
+	c->mul = 1;
+	tegra2_clk_recalculate_rate(c);
+}
+
+static int tegra2_bus_clk_enable(struct clk *c)
+{
+	u32 val = clk_readl(c->reg);
+	val &= ~(BUS_CLK_DISABLE << c->reg_shift);
+	clk_writel(val, c->reg);
+	return 0;
+}
+
+static void tegra2_bus_clk_disable(struct clk *c)
+{
+	u32 val = clk_readl(c->reg);
+	val |= BUS_CLK_DISABLE << c->reg_shift;
+	clk_writel(val, c->reg);
+}
+
+static int tegra2_bus_clk_set_rate(struct clk *c, unsigned long rate)
+{
+	u32 val = clk_readl(c->reg);
+	unsigned long parent_rate = c->parent->rate;
+	int i;
+	for (i = 1; i <= 4; i++) {
+		if (rate == parent_rate / i) {
+			val &= ~(BUS_CLK_DIV_MASK << c->reg_shift);
+			val |= (i - 1) << c->reg_shift;
+			clk_writel(val, c->reg);
+			c->div = i;
+			c->mul = 1;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static struct clk_ops tegra_bus_ops = {
+	.init			= tegra2_bus_clk_init,
+	.enable			= tegra2_bus_clk_enable,
+	.disable		= tegra2_bus_clk_disable,
+	.set_rate		= tegra2_bus_clk_set_rate,
+	.recalculate_rate	= tegra2_clk_recalculate_rate,
+};
+
+/* PLL Functions */
+static unsigned long tegra2_pll_clk_recalculate_rate(struct clk *c)
+{
+	u64 rate;
+	rate = c->parent->rate;
+	rate *= c->n;
+	do_div(rate, c->m);
+	if (c->p == 2)
+		rate >>= 1;
+	c->rate = rate;
+	return c->rate;
+}
+
+static int tegra2_pll_clk_w