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

3 files changed, 559 insertions, 5 deletions

diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
new file mode 100644
index 00000000000..5e4312b6f5c
--- /dev/null
+++ b/include/linux/clk-private.h
@@ -0,0 +1,196 @@
+/*
+ *  linux/include/linux/clk-private.h
+ *
+ *  Copyright (c) 2010-2011 Jeremy Kerr <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.
+ */
+#ifndef __LINUX_CLK_PRIVATE_H
+#define __LINUX_CLK_PRIVATE_H
+
+#include <linux/clk-provider.h>
+#include <linux/list.h>
+
+/*
+ * WARNING: Do not include clk-private.h from any file that implements struct
+ * clk_ops.  Doing so is a layering violation!
+ *
+ * This header exists only to allow for statically initialized clock data.  Any
+ * static clock data must be defined in a separate file from the logic that
+ * implements the clock operations for that same data.
+ */
+
+#ifdef CONFIG_COMMON_CLK
+
+struct clk {
+	const char		*name;
+	const struct clk_ops	*ops;
+	struct clk_hw		*hw;
+	struct clk		*parent;
+	char			**parent_names;
+	struct clk		**parents;
+	u8			num_parents;
+	unsigned long		rate;
+	unsigned long		new_rate;
+	unsigned long		flags;
+	unsigned int		enable_count;
+	unsigned int		prepare_count;
+	struct hlist_head	children;
+	struct hlist_node	child_node;
+	unsigned int		notifier_count;
+#ifdef CONFIG_COMMON_CLK_DEBUG
+	struct dentry		*dentry;
+#endif
+};
+
+/*
+ * DOC: Basic clock implementations common to many platforms
+ *
+ * Each basic clock hardware type is comprised of a structure describing the
+ * clock hardware, implementations of the relevant callbacks in struct clk_ops,
+ * unique flags for that hardware type, a registration function and an
+ * alternative macro for static initialization
+ */
+
+extern struct clk_ops clk_fixed_rate_ops;
+
+#define DEFINE_CLK_FIXED_RATE(_name, _flags, _rate,		\
+				_fixed_rate_flags)		\
+	static struct clk _name;				\
+	static char *_name##_parent_names[] = {};		\
+	static struct clk_fixed_rate _name##_hw = {		\
+		.hw = {						\
+			.clk = &_name,				\
+		},						\
+		.fixed_rate = _rate,				\
+		.flags = _fixed_rate_flags,			\
+	};							\
+	static struct clk _name = {				\
+		.name = #_name,					\
+		.ops = &clk_fixed_rate_ops,			\
+		.hw = &_name##_hw.hw,				\
+		.parent_names = _name##_parent_names,		\
+		.num_parents =					\
+			ARRAY_SIZE(_name##_parent_names),	\
+		.flags = _flags,				\
+	};
+
+extern struct clk_ops clk_gate_ops;
+
+#define DEFINE_CLK_GATE(_name, _parent_name, _parent_ptr,	\
+				_flags, _reg, _bit_idx,		\
+				_gate_flags, _lock)		\
+	static struct clk _name;				\
+	static char *_name##_parent_names[] = {			\
+		_parent_name,					\
+	};							\
+	static struct clk *_name##_parents[] = {		\
+		_parent_ptr,					\
+	};							\
+	static struct clk_gate _name##_hw = {			\
+		.hw = {						\
+			.clk = &_name,				\
+		},						\
+		.reg = _reg,					\
+		.bit_idx = _bit_idx,				\
+		.flags = _gate_flags,				\
+		.lock = _lock,					\
+	};							\
+	static struct clk _name = {				\
+		.name = #_name,					\
+		.ops = &clk_gate_ops,				\
+		.hw = &_name##_hw.hw,				\
+		.parent_names = _name##_parent_names,		\
+		.num_parents =					\
+			ARRAY_SIZE(_name##_parent_names),	\
+		.parents = _name##_parents,			\
+		.flags = _flags,				\
+	};
+
+extern struct clk_ops clk_divider_ops;
+
+#define DEFINE_CLK_DIVIDER(_name, _parent_name, _parent_ptr,	\
+				_flags, _reg, _shift, _width,	\
+				_divider_flags, _lock)		\
+	static struct clk _name;				\
+	static char *_name##_parent_names[] = {			\
+		_parent_name,					\
+	};							\
+	static struct clk *_name##_parents[] = {		\
+		_parent_ptr,					\
+	};							\
+	static struct clk_divider _name##_hw = {		\
+		.hw = {						\
+			.clk = &_name,				\
+		},						\
+		.reg = _reg,					\
+		.shift = _shift,				\
+		.width = _width,				\
+		.flags = _divider_flags,			\
+		.lock = _lock,					\
+	};							\
+	static struct clk _name = {				\
+		.name = #_name,					\
+		.ops = &clk_divider_ops,			\
+		.hw = &_name##_hw.hw,				\
+		.parent_names = _name##_parent_names,		\
+		.num_parents =					\
+			ARRAY_SIZE(_name##_parent_names),	\
+		.parents = _name##_parents,			\
+		.flags = _flags,				\
+	};
+
+extern struct clk_ops clk_mux_ops;
+
+#define DEFINE_CLK_MUX(_name, _parent_names, _parents, _flags,	\
+				_reg, _shift, _width,		\
+				_mux_flags, _lock)		\
+	static struct clk _name;				\
+	static struct clk_mux _name##_hw = {			\
+		.hw = {						\
+			.clk = &_name,				\
+		},						\
+		.reg = _reg,					\
+		.shift = _shift,				\
+		.width = _width,				\
+		.flags = _mux_flags,				\
+		.lock = _lock,					\
+	};							\
+	static struct clk _name = {				\
+		.name = #_name,					\
+		.ops = &clk_mux_ops,				\
+		.hw = &_name##_hw.hw,				\
+		.parent_names = _parent_names,			\
+		.num_parents =					\
+			ARRAY_SIZE(_parent_names),		\
+		.parents = _parents,				\
+		.flags = _flags,				\
+	};
+
+/**
+ * __clk_init - initialize the data structures in a struct clk
+ * @dev:	device initializing this clk, placeholder for now
+ * @clk:	clk being initialized
+ *
+ * Initializes the lists in struct clk, queries the hardware for the
+ * parent and rate and sets them both.
+ *
+ * Any struct clk passed into __clk_init must have the following members
+ * populated:
+ * 	.name
+ * 	.ops
+ * 	.hw
+ * 	.parent_names
+ * 	.num_parents
+ * 	.flags
+ *
+ * It is not necessary to call clk_register if __clk_init is used directly with
+ * statically initialized clock data.
+ */
+void __clk_init(struct device *dev, struct clk *clk);
+
+#endif /* CONFIG_COMMON_CLK */
+#endif /* CLK_PRIVATE_H */
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
new file mode 100644
index 00000000000..5508897ad37
--- /dev/null
+++ b/include/linux/clk-provider.h
@@ -0,0 +1,300 @@
+/*
+ *  linux/include/linux/clk-provider.h
+ *
+ *  Copyright (c) 2010-2011 Jeremy Kerr <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.
+ */
+#ifndef __LINUX_CLK_PROVIDER_H
+#define __LINUX_CLK_PROVIDER_H
+
+#include <linux/clk.h>
+
+#ifdef CONFIG_COMMON_CLK
+
+/**
+ * struct clk_hw - handle for traversing from a struct clk to its corresponding
+ * hardware-specific structure.  struct clk_hw should be declared within struct
+ * clk_foo and then referenced by the struct clk instance that uses struct
+ * clk_foo's clk_ops
+ *
+ * clk: pointer to the struct clk instance that points back to this struct
+ * clk_hw instance
+ */
+struct clk_hw {
+	struct clk *clk;
+};
+
+/*
+ * flags used across common struct clk.  these flags should only affect the
+ * top-level framework.  custom flags for dealing with hardware specifics
+ * belong in struct clk_foo
+ */
+#define CLK_SET_RATE_GATE	BIT(0) /* must be gated across rate change */
+#define CLK_SET_PARENT_GATE	BIT(1) /* must be gated across re-parent */
+#define CLK_SET_RATE_PARENT	BIT(2) /* propagate rate change up one level */
+#define CLK_IGNORE_UNUSED	BIT(3) /* do not gate even if unused */
+#define CLK_IS_ROOT		BIT(4) /* root clk, has no parent */
+
+/**
+ * struct clk_ops -  Callback operations for hardware clocks; these are to
+ * be provided by the clock implementation, and will be called by drivers
+ * through the clk_* api.
+ *
+ * @prepare:	Prepare the clock for enabling. This must not return until
+ * 		the clock is fully prepared, and it's safe to call clk_enable.
+ * 		This callback is intended to allow clock implementations to
+ * 		do any initialisation that may sleep. Called with
+ * 		prepare_lock held.
+ *
+ * @unprepare:	Release the clock from its prepared state. This will typically
+ * 		undo any work done in the @prepare callback. Called with
+ * 		prepare_lock held.
+ *
+ * @enable:	Enable the clock atomically. This must not return until the
+ * 		clock is generating a valid clock signal, usable by consumer
+ * 		devices. Called with enable_lock held. This function must not
+ * 		sleep.
+ *
+ * @disable:	Disable the clock atomically. Called with enable_lock held.
+ * 		This function must not sleep.
+ *
+ * @recalc_rate	Recalculate the rate of this clock, by quering hardware.  The
+ * 		parent rate is an input parameter.  It is up to the caller to
+ * 		insure that the prepare_mutex is held across this call.
+ * 		Returns the calculated rate.  Optional, but recommended - if
+ * 		this op is not set then clock rate will be initialized to 0.
+ *
+ * @round_rate:	Given a target rate as input, returns the closest rate actually
+ * 		supported by the clock.
+ *
+ * @get_parent:	Queries the hardware to determine the parent of a clock.  The
+ * 		return value is a u8 which specifies the index corresponding to
+ * 		the parent clock.  This index can be applied to either the
+ * 		.parent_names or .parents arrays.  In short, this function
+ * 		translates the parent value read from hardware into an array
+ * 		index.  Currently only called when the clock is initialized by
+ * 		__clk_init.  This callback is mandatory for clocks with
+ * 		multiple parents.  It is optional (and unnecessary) for clocks
+ * 		with 0 or 1 parents.
+ *
+ * @set_parent:	Change the input source of this clock; for clocks with multiple
+ * 		possible parents specify a new parent by passing in the index
+ * 		as a u8 corresponding to the parent in either the .parent_names
+ * 		or .parents arrays.  This function in affect translates an
+ * 		array index into the value programmed into the hardware.
+ * 		Returns 0 on success, -EERROR otherwise.
+ *
+ * @set_rate:	Change the rate of this clock. If this callback returns
+ * 		CLK_SET_RATE_PARENT, the rate change will be propagated to the
+ * 		parent clock (which may propagate again if the parent clock
+ * 		also sets this flag). The requested rate of the parent is
+ * 		passed back from the callback in the second 'unsigned long *'
+ * 		argument.  Note that it is up to the hardware clock's set_rate
+ * 		implementation to insure that clocks do not run out of spec
+ * 		when propgating the call to set_rate up to the parent.  One way
+ * 		to do this is to gate the clock (via clk_disable and/or
+ * 		clk_unprepare) before calling clk_set_rate, then ungating it
+ * 		afterward.  If your clock also has the CLK_GATE_SET_RATE flag
+ * 		set then this will insure safety.  Returns 0 on success,
+ * 		-EERROR otherwise.
+ *
+ * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
+ * implementations to split any work between atomic (enable) and sleepable
+ * (prepare) contexts.  If enabling a clock requires code that might sleep,
+ * this must be done in clk_prepare.  Clock enable code that will never be
+ * called in a sleepable context may be implement in clk_enable.
+ *
+ * Typically, drivers will call clk_prepare when a clock may be needed later
+ * (eg. when a device is opened), and clk_enable when the clock is actually
+ * required (eg. from an interrupt). Note that clk_prepare MUST have been
+ * called before clk_enable.
+ */
+struct clk_ops {
+	int		(*prepare)(struct clk_hw *hw);
+	void		(*unprepare)(struct clk_hw *hw);
+	int		(*enable)(struct clk_hw *hw);
+	void		(*disable)(struct clk_hw *hw);
+	int		(*is_enabled)(struct clk_hw *hw);
+	unsigned long	(*recalc_rate)(struct clk_hw *hw,
+					unsigned long parent_rate);
+	long		(*round_rate)(struct clk_hw *hw, unsigned long,
+					unsigned long *);
+	int		(*set_parent)(struct clk_hw *hw, u8 index);
+	u8		(*get_parent)(struct clk_hw *hw);
+	int		(*set_rate)(struct clk_hw *hw, unsigned long);
+	void		(*init)(struct clk_hw *hw);
+};
+
+/*
+ * DOC: Basic clock implementations common to many platforms
+ *
+ * Each basic clock hardware type is comprised of a structure describing the
+ * clock hardware, implementations of the relevant callbacks in struct clk_ops,
+ * unique flags for that hardware type, a registration function and an
+ * alternative macro for static initialization
+ */
+
+/**
+ * struct clk_fixed_rate - fixed-rate clock
+ * @hw:		handle between common and hardware-specific interfaces
+ * @fixed_rate:	constant frequency of clock
+ */
+struct clk_fixed_rate {
+	struct		clk_hw hw;
+	unsigned long	fixed_rate;
+	u8		flags;
+};
+
+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_gate - gating clock
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @reg:	register controlling gate
+ * @bit_idx:	single bit controlling gate
+ * @flags:	hardware-specific flags
+ * @lock:	register lock
+ *
+ * Clock which can gate its output.  Implements .enable & .disable
+ *
+ * Flags:
+ * CLK_GATE_SET_DISABLE - by default this clock sets the bit at bit_idx to
+ * 	enable the clock.  Setting this flag does the opposite: setting the bit
+ * 	disable the clock and clearing it enables the clock
+ */
+struct clk_gate {
+	struct clk_hw hw;
+	void __iomem	*reg;
+	u8		bit_idx;
+	u8		flags;
+	spinlock_t	*lock;
+	char		*parent[1];
+};
+
+#define CLK_GATE_SET_TO_DISABLE		BIT(0)
+
+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_divider - adjustable divider clock
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @reg:	register containing the divider
+ * @shift:	shift to the divider bit field
+ * @width:	width of the divider bit field
+ * @lock:	register lock
+ *
+ * Clock with an adjustable divider affecting its output frequency.  Implements
+ * .recalc_rate, .set_rate and .round_rate
+ *
+ * Flags:
+ * CLK_DIVIDER_ONE_BASED - by default the divisor is the value read from the
+ * 	register plus one.  If CLK_DIVIDER_ONE_BASED is set then the divider is
+ * 	the raw value read from the register, with the value of zero considered
+ * 	invalid
+ * CLK_DIVIDER_POWER_OF_TWO - clock divisor is 2 raised to the value read from
+ * 	the hardware register
+ */
+struct clk_divider {
+	struct clk_hw	hw;
+	void __iomem	*reg;
+	u8		shift;
+	u8		width;
+	u8		flags;
+	spinlock_t	*lock;
+	char		*parent[1];
+};
+
+#define CLK_DIVIDER_ONE_BASED		BIT(0)
+#define CLK_DIVIDER_POWER_OF_TWO	BIT(1)
+
+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_mux - multiplexer clock
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @reg:	register controlling multiplexer
+ * @shift:	shift to multiplexer bit field
+ * @width:	width of mutliplexer bit field
+ * @num_clks:	number of parent clocks
+ * @lock:	register lock
+ *
+ * Clock with multiple selectable parents.  Implements .get_parent, .set_parent
+ * and .recalc_rate
+ *
+ * Flags:
+ * CLK_MUX_INDEX_ONE - register index starts at 1, not 0
+ * CLK_MUX_INDEX_BITWISE - register index is a single bit (power of two)
+ */
+struct clk_mux {
+	struct clk_hw	hw;
+	void __iomem	*reg;
+	u8		shift;
+	u8		width;
+	u8		flags;
+	spinlock_t	*lock;
+};
+
+#define CLK_MUX_INDEX_ONE		BIT(0)
+#define CLK_MUX_INDEX_BIT		BIT(1)
+
+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);
+
+/**
+ * clk_register - allocate a new clock, register it and return an opaque cookie
+ * @dev: device that is registering this clock
+ * @name: clock name
+ * @ops: operations this clock supports
+ * @hw: link to hardware-specific clock data
+ * @parent_names: array of string names for all possible parents
+ * @num_parents: number of possible parents
+ * @flags: framework-level hints and quirks
+ *
+ * clk_register is the primary interface for populating the clock tree with new
+ * clock nodes.  It returns a pointer to the newly allocated struct clk which
+ * cannot be dereferenced by driver code but may be used in conjuction with the
+ * rest of the clock API.
+ */
+struct clk *clk_register(struct device *dev, const char *name,
+		const struct clk_ops *ops, struct clk_hw *hw,
+		char **parent_names, u8 num_parents, unsigned long flags);
+
+/* helper functions */
+const char *__clk_get_name(struct clk *clk);
+struct clk_hw *__clk_get_hw(struct clk *clk);
+u8 __clk_get_num_parents(struct clk *clk);
+struct clk *__clk_get_parent(struct clk *clk);
+inline int __clk_get_enable_count(struct clk *clk);
+inline int __clk_get_prepare_count(struct clk *clk);
+unsigned long __clk_get_rate(struct clk *clk);
+unsigned long __clk_get_flags(struct clk *clk);
+int __clk_is_enabled(struct clk *clk);
+struct clk *__clk_lookup(const char *name);
+
+/*
+ * FIXME clock api without lock protection
+ */
+int __clk_prepare(struct clk *clk);
+void __clk_unprepare(struct clk *clk);
+void __clk_reparent(struct clk *clk, struct clk *new_parent);
+unsigned long __clk_round_rate(struct clk *clk, unsigned long rate);
+
+#endif /* CONFIG_COMMON_CLK */
+#endif /* CLK_PROVIDER_H */
diff --git a/include/linux/clk.h b/include/linux/clk.h
index b9d46fa154b..b0252726df6 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -3,6 +3,7 @@
  *
  *  Copyright (C) 2004 ARM Limited.
  *  Written by Deep Blue Solutions Limited.
+ *  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
@@ -12,18 +13,75 @@
 #define __LINUX_CLK_H
 
 #include <linux/kernel.h>
+#include <linux/notifier.h>
 
 struct device;
 
-/*
- * The base API.
+struct clk;
+
+#ifdef CONFIG_COMMON_CLK
+
+/**
+ * DOC: clk notifier callback types
+ *
+ * PRE_RATE_CHANGE - called immediately before the clk rate is changed,
+ *     to indicate that the rate change will proceed.  Drivers must
+ *     immediately terminate any operations that will be affected by the
+ *     rate change.  Callbacks may either return NOTIFY_DONE or
+ *     NOTIFY_STOP.
+ *
+ * ABORT_RATE_CHANGE: called if the rate change failed for some reason
+ *     after PRE_RATE_CHANGE.  In this case, all registered notifiers on
+ *     the clk will be called with ABORT_RATE_CHANGE. Callbacks must
+ *     always return NOTIFY_DONE.
+ *
+ * POST_RATE_CHANGE - called after the clk rate change has successfully
+ *     completed.  Callbacks must always return NOTIFY_DONE.
+ *
  */
+#define PRE_RATE_CHANGE			BIT(0)
+#define POST_RATE_CHANGE		BIT(1)
+#define ABORT_RATE_CHANGE		BIT(2)
 
+/**
+ * struct clk_notifier - associate a clk with a notifier
+ * @clk: struct clk * to associate the notifier with
+ * @notifier_head: a blocking_notifier_head for this clk
+ * @node: linked list pointers
+ *
+ * A list of struct clk_notifier is maintained by the notifier code.
+ * An entry is created whenever code registers the first notifier on a
+ * particular @clk.  Future notifiers on that @clk are added to the
+ * @notifier_head.
+ */
+struct clk_notifier {
+	struct clk			*clk;
+	struct srcu_notifier_head	notifier_head;
+	struct list_head		node;
+};
 
-/*
- * struct clk - an machine class defined object / cookie.
+/**
+ * struct clk_notifier_data - rate data to pass to the notifier callback
+ * @clk: struct clk * being changed
+ * @old_rate: previous rate of this clk
+ * @new_rate: new rate of this clk
+ *
+ * For a pre-notifier, old_rate is the clk's rate before this rate
+ * change, and new_rate is what the rate will be in the future.  For a
+ * post-notifier, old_rate and new_rate are both set to the clk's
+ * current rate (this was done to optimize the implementation).
  */
-struct clk;
+struct clk_notifier_data {
+	struct clk		*clk;
+	unsigned long		old_rate;
+	unsigned long		new_rate;
+};
+
+int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
+
+int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
+
+#endif /* !CONFIG_COMMON_CLK */
 
 /**
  * clk_get - lookup and obtain a reference to a clock producer.