Current File : //usr/src/kernels/3.10.0-957.21.3.el7.centos.plus.x86_64/include/linux/clk.h
/*
* linux/include/linux/clk.h
*
* 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
* published by the Free Software Foundation.
*/
#ifndef __LINUX_CLK_H
#define __LINUX_CLK_H
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/notifier.h>
struct device;
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, NOTIFY_OK,
* NOTIFY_STOP or NOTIFY_BAD.
*
* 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 or NOTIFY_OK.
*
* POST_RATE_CHANGE - called after the clk rate change has successfully
* completed. Callbacks must always return NOTIFY_DONE or NOTIFY_OK.
*
*/
#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_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_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
/**
* clk_prepare - prepare a clock source
* @clk: clock source
*
* This prepares the clock source for use.
*
* Must not be called from within atomic context.
*/
#ifdef CONFIG_HAVE_CLK_PREPARE
int clk_prepare(struct clk *clk);
#else
static inline int clk_prepare(struct clk *clk)
{
might_sleep();
return 0;
}
#endif
/**
* clk_unprepare - undo preparation of a clock source
* @clk: clock source
*
* This undoes a previously prepared clock. The caller must balance
* the number of prepare and unprepare calls.
*
* Must not be called from within atomic context.
*/
#ifdef CONFIG_HAVE_CLK_PREPARE
void clk_unprepare(struct clk *clk);
#else
static inline void clk_unprepare(struct clk *clk)
{
might_sleep();
}
#endif
#ifdef CONFIG_HAVE_CLK
/**
* clk_get - lookup and obtain a reference to a clock producer.
* @dev: device for clock "consumer"
* @id: clock consumer ID
*
* Returns a struct clk corresponding to the clock producer, or
* valid IS_ERR() condition containing errno. The implementation
* uses @dev and @id to determine the clock consumer, and thereby
* the clock producer. (IOW, @id may be identical strings, but
* clk_get may return different clock producers depending on @dev.)
*
* Drivers must assume that the clock source is not enabled.
*
* clk_get should not be called from within interrupt context.
*/
struct clk *clk_get(struct device *dev, const char *id);
/**
* devm_clk_get - lookup and obtain a managed reference to a clock producer.
* @dev: device for clock "consumer"
* @id: clock consumer ID
*
* Returns a struct clk corresponding to the clock producer, or
* valid IS_ERR() condition containing errno. The implementation
* uses @dev and @id to determine the clock consumer, and thereby
* the clock producer. (IOW, @id may be identical strings, but
* clk_get may return different clock producers depending on @dev.)
*
* Drivers must assume that the clock source is not enabled.
*
* devm_clk_get should not be called from within interrupt context.
*
* The clock will automatically be freed when the device is unbound
* from the bus.
*/
struct clk *devm_clk_get(struct device *dev, const char *id);
/**
* clk_enable - inform the system when the clock source should be running.
* @clk: clock source
*
* If the clock can not be enabled/disabled, this should return success.
*
* May be called from atomic contexts.
*
* Returns success (0) or negative errno.
*/
int clk_enable(struct clk *clk);
/**
* clk_disable - inform the system when the clock source is no longer required.
* @clk: clock source
*
* Inform the system that a clock source is no longer required by
* a driver and may be shut down.
*
* May be called from atomic contexts.
*
* Implementation detail: if the clock source is shared between
* multiple drivers, clk_enable() calls must be balanced by the
* same number of clk_disable() calls for the clock source to be
* disabled.
*/
void clk_disable(struct clk *clk);
/**
* clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
* This is only valid once the clock source has been enabled.
* @clk: clock source
*/
unsigned long clk_get_rate(struct clk *clk);
/**
* clk_put - "free" the clock source
* @clk: clock source
*
* Note: drivers must ensure that all clk_enable calls made on this
* clock source are balanced by clk_disable calls prior to calling
* this function.
*
* clk_put should not be called from within interrupt context.
*/
void clk_put(struct clk *clk);
/**
* devm_clk_put - "free" a managed clock source
* @dev: device used to acuqire the clock
* @clk: clock source acquired with devm_clk_get()
*
* Note: drivers must ensure that all clk_enable calls made on this
* clock source are balanced by clk_disable calls prior to calling
* this function.
*
* clk_put should not be called from within interrupt context.
*/
void devm_clk_put(struct device *dev, struct clk *clk);
/*
* The remaining APIs are optional for machine class support.
*/
/**
* clk_round_rate - adjust a rate to the exact rate a clock can provide
* @clk: clock source
* @rate: desired clock rate in Hz
*
* Returns rounded clock rate in Hz, or negative errno.
*/
long clk_round_rate(struct clk *clk, unsigned long rate);
/**
* clk_set_rate - set the clock rate for a clock source
* @clk: clock source
* @rate: desired clock rate in Hz
*
* Returns success (0) or negative errno.
*/
int clk_set_rate(struct clk *clk, unsigned long rate);
/**
* clk_set_parent - set the parent clock source for this clock
* @clk: clock source
* @parent: parent clock source
*
* Returns success (0) or negative errno.
*/
int clk_set_parent(struct clk *clk, struct clk *parent);
/**
* clk_get_parent - get the parent clock source for this clock
* @clk: clock source
*
* Returns struct clk corresponding to parent clock source, or
* valid IS_ERR() condition containing errno.
*/
struct clk *clk_get_parent(struct clk *clk);
/**
* clk_get_sys - get a clock based upon the device name
* @dev_id: device name
* @con_id: connection ID
*
* Returns a struct clk corresponding to the clock producer, or
* valid IS_ERR() condition containing errno. The implementation
* uses @dev_id and @con_id to determine the clock consumer, and
* thereby the clock producer. In contrast to clk_get() this function
* takes the device name instead of the device itself for identification.
*
* Drivers must assume that the clock source is not enabled.
*
* clk_get_sys should not be called from within interrupt context.
*/
struct clk *clk_get_sys(const char *dev_id, const char *con_id);
#else /* !CONFIG_HAVE_CLK */
static inline struct clk *clk_get(struct device *dev, const char *id)
{
return NULL;
}
static inline struct clk *devm_clk_get(struct device *dev, const char *id)
{
return NULL;
}
static inline void clk_put(struct clk *clk) {}
static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
static inline int clk_enable(struct clk *clk)
{
return 0;
}
static inline void clk_disable(struct clk *clk) {}
static inline unsigned long clk_get_rate(struct clk *clk)
{
return 0;
}
static inline int clk_set_rate(struct clk *clk, unsigned long rate)
{
return 0;
}
static inline long clk_round_rate(struct clk *clk, unsigned long rate)
{
return 0;
}
static inline int clk_set_parent(struct clk *clk, struct clk *parent)
{
return 0;
}
static inline struct clk *clk_get_parent(struct clk *clk)
{
return NULL;
}
#endif
/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
static inline int clk_prepare_enable(struct clk *clk)
{
int ret;
ret = clk_prepare(clk);
if (ret)
return ret;
ret = clk_enable(clk);
if (ret)
clk_unprepare(clk);
return ret;
}
/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
static inline void clk_disable_unprepare(struct clk *clk)
{
clk_disable(clk);
clk_unprepare(clk);
}
/**
* clk_add_alias - add a new clock alias
* @alias: name for clock alias
* @alias_dev_name: device name
* @id: platform specific clock name
* @dev: device
*
* Allows using generic clock names for drivers by adding a new alias.
* Assumes clkdev, see clkdev.h for more info.
*/
int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
struct device *dev);
struct device_node;
struct of_phandle_args;
#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
struct clk *of_clk_get(struct device_node *np, int index);
struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
#else
static inline struct clk *of_clk_get(struct device_node *np, int index)
{
return ERR_PTR(-ENOENT);
}
static inline struct clk *of_clk_get_by_name(struct device_node *np,
const char *name)
{
return ERR_PTR(-ENOENT);
}
#endif
#endif
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