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/*
* linux/include/linux/clk.h
*
* Copyright (C) 2004 ARM Limited.
* Written by Deep Blue Solutions Limited.
*
* 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/kernel.h>
struct device;
/*
* The base API.
*/
/*
* struct clk - an machine class defined object / cookie.
*/
struct clk;
/**
* clk_get - lookup and obtain a reference to a clock producer.
* @dev: device for clock "consumer"
* @id: clock comsumer 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);
/**
* 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_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_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
/* 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_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);
/*
* 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);
/**
* 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);
#endif
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