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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

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.

 */

struct clk *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.

 *

 * 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.

 *

 * 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.

 */

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);

#endif