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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 23:38:06 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 23:38:06 +0400
commit735e941caa9a35f933297af0ab1e0ad6447411c4 (patch)
treead05f19a0e748061d743f9f4d99cde9923b192c2 /include/linux
parent09893ee84591b0417a9186a7e7cf1503ccf99ac2 (diff)
parent8fb61e33507e5d76b69467b4f96290338e96b733 (diff)
downloadlinux-735e941caa9a35f933297af0ab1e0ad6447411c4.tar.xz
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
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/clk-private.h196
-rw-r--r--include/linux/clk-provider.h300
-rw-r--r--include/linux/clk.h68
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 000000000000..5e4312b6f5cc
--- /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 000000000000..5508897ad376
--- /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 b9d46fa154b4..b0252726df61 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.