e12ff34402
* depends/rmk/clkdev: CLKDEV: provide helpers for common clock framework ARM: 7392/1: CLKDEV: Optimize clk_find() ARM: 7376/1: clkdev: Implement managed clk_get()
313 lines
8.9 KiB
C
313 lines
8.9 KiB
C
/*
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* linux/include/linux/clk.h
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*
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* Copyright (C) 2004 ARM Limited.
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* Written by Deep Blue Solutions Limited.
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* Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __LINUX_CLK_H
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#define __LINUX_CLK_H
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#include <linux/kernel.h>
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#include <linux/notifier.h>
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struct device;
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struct clk;
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#ifdef CONFIG_COMMON_CLK
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/**
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* DOC: clk notifier callback types
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*
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* PRE_RATE_CHANGE - called immediately before the clk rate is changed,
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* to indicate that the rate change will proceed. Drivers must
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* immediately terminate any operations that will be affected by the
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* rate change. Callbacks may either return NOTIFY_DONE or
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* NOTIFY_STOP.
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*
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* ABORT_RATE_CHANGE: called if the rate change failed for some reason
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* after PRE_RATE_CHANGE. In this case, all registered notifiers on
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* the clk will be called with ABORT_RATE_CHANGE. Callbacks must
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* always return NOTIFY_DONE.
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*
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* POST_RATE_CHANGE - called after the clk rate change has successfully
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* completed. Callbacks must always return NOTIFY_DONE.
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*
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*/
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#define PRE_RATE_CHANGE BIT(0)
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#define POST_RATE_CHANGE BIT(1)
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#define ABORT_RATE_CHANGE BIT(2)
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/**
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* struct clk_notifier - associate a clk with a notifier
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* @clk: struct clk * to associate the notifier with
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* @notifier_head: a blocking_notifier_head for this clk
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* @node: linked list pointers
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*
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* A list of struct clk_notifier is maintained by the notifier code.
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* An entry is created whenever code registers the first notifier on a
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* particular @clk. Future notifiers on that @clk are added to the
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* @notifier_head.
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*/
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struct clk_notifier {
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struct clk *clk;
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struct srcu_notifier_head notifier_head;
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struct list_head node;
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};
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/**
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* struct clk_notifier_data - rate data to pass to the notifier callback
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* @clk: struct clk * being changed
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* @old_rate: previous rate of this clk
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* @new_rate: new rate of this clk
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*
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* For a pre-notifier, old_rate is the clk's rate before this rate
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* change, and new_rate is what the rate will be in the future. For a
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* post-notifier, old_rate and new_rate are both set to the clk's
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* current rate (this was done to optimize the implementation).
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*/
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struct clk_notifier_data {
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struct clk *clk;
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unsigned long old_rate;
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unsigned long new_rate;
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};
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int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
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int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
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#endif
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/**
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* clk_get - lookup and obtain a reference to a clock producer.
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* @dev: device for clock "consumer"
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* @id: clock comsumer ID
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*
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* Returns a struct clk corresponding to the clock producer, or
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* valid IS_ERR() condition containing errno. The implementation
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* uses @dev and @id to determine the clock consumer, and thereby
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* the clock producer. (IOW, @id may be identical strings, but
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* clk_get may return different clock producers depending on @dev.)
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*
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* Drivers must assume that the clock source is not enabled.
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*
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* clk_get should not be called from within interrupt context.
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*/
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struct clk *clk_get(struct device *dev, const char *id);
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/**
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* devm_clk_get - lookup and obtain a managed reference to a clock producer.
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* @dev: device for clock "consumer"
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* @id: clock comsumer ID
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*
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* Returns a struct clk corresponding to the clock producer, or
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* valid IS_ERR() condition containing errno. The implementation
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* uses @dev and @id to determine the clock consumer, and thereby
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* the clock producer. (IOW, @id may be identical strings, but
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* clk_get may return different clock producers depending on @dev.)
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*
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* Drivers must assume that the clock source is not enabled.
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*
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* devm_clk_get should not be called from within interrupt context.
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*
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* The clock will automatically be freed when the device is unbound
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* from the bus.
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*/
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struct clk *devm_clk_get(struct device *dev, const char *id);
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/**
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* clk_prepare - prepare a clock source
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* @clk: clock source
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*
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* This prepares the clock source for use.
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*
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* Must not be called from within atomic context.
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*/
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#ifdef CONFIG_HAVE_CLK_PREPARE
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int clk_prepare(struct clk *clk);
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#else
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static inline int clk_prepare(struct clk *clk)
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{
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might_sleep();
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return 0;
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}
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#endif
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/**
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* clk_enable - inform the system when the clock source should be running.
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* @clk: clock source
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*
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* If the clock can not be enabled/disabled, this should return success.
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*
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* May be called from atomic contexts.
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*
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* Returns success (0) or negative errno.
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*/
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int clk_enable(struct clk *clk);
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/**
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* clk_disable - inform the system when the clock source is no longer required.
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* @clk: clock source
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*
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* Inform the system that a clock source is no longer required by
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* a driver and may be shut down.
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*
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* May be called from atomic contexts.
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*
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* Implementation detail: if the clock source is shared between
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* multiple drivers, clk_enable() calls must be balanced by the
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* same number of clk_disable() calls for the clock source to be
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* disabled.
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*/
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void clk_disable(struct clk *clk);
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/**
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* clk_unprepare - undo preparation of a clock source
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* @clk: clock source
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*
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* This undoes a previously prepared clock. The caller must balance
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* the number of prepare and unprepare calls.
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*
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* Must not be called from within atomic context.
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*/
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#ifdef CONFIG_HAVE_CLK_PREPARE
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void clk_unprepare(struct clk *clk);
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#else
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static inline void clk_unprepare(struct clk *clk)
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{
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might_sleep();
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}
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#endif
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/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
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static inline int clk_prepare_enable(struct clk *clk)
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{
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int ret;
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ret = clk_prepare(clk);
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if (ret)
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return ret;
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ret = clk_enable(clk);
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if (ret)
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clk_unprepare(clk);
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return ret;
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}
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/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
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static inline void clk_disable_unprepare(struct clk *clk)
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{
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clk_disable(clk);
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clk_unprepare(clk);
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}
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/**
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* clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
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* This is only valid once the clock source has been enabled.
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* @clk: clock source
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*/
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unsigned long clk_get_rate(struct clk *clk);
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/**
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* clk_put - "free" the clock source
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* @clk: clock source
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*
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* Note: drivers must ensure that all clk_enable calls made on this
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* clock source are balanced by clk_disable calls prior to calling
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* this function.
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*
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* clk_put should not be called from within interrupt context.
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*/
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void clk_put(struct clk *clk);
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/**
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* devm_clk_put - "free" a managed clock source
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* @dev: device used to acuqire the clock
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* @clk: clock source acquired with devm_clk_get()
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*
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* Note: drivers must ensure that all clk_enable calls made on this
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* clock source are balanced by clk_disable calls prior to calling
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* this function.
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*
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* clk_put should not be called from within interrupt context.
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*/
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void devm_clk_put(struct device *dev, struct clk *clk);
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/*
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* The remaining APIs are optional for machine class support.
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*/
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/**
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* clk_round_rate - adjust a rate to the exact rate a clock can provide
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* @clk: clock source
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* @rate: desired clock rate in Hz
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*
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* Returns rounded clock rate in Hz, or negative errno.
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*/
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long clk_round_rate(struct clk *clk, unsigned long rate);
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/**
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* clk_set_rate - set the clock rate for a clock source
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* @clk: clock source
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* @rate: desired clock rate in Hz
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*
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* Returns success (0) or negative errno.
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*/
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int clk_set_rate(struct clk *clk, unsigned long rate);
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/**
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* clk_set_parent - set the parent clock source for this clock
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* @clk: clock source
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* @parent: parent clock source
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*
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* Returns success (0) or negative errno.
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*/
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int clk_set_parent(struct clk *clk, struct clk *parent);
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/**
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* clk_get_parent - get the parent clock source for this clock
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* @clk: clock source
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*
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* Returns struct clk corresponding to parent clock source, or
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* valid IS_ERR() condition containing errno.
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*/
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struct clk *clk_get_parent(struct clk *clk);
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/**
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* clk_get_sys - get a clock based upon the device name
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* @dev_id: device name
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* @con_id: connection ID
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*
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* Returns a struct clk corresponding to the clock producer, or
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* valid IS_ERR() condition containing errno. The implementation
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* uses @dev_id and @con_id to determine the clock consumer, and
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* thereby the clock producer. In contrast to clk_get() this function
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* takes the device name instead of the device itself for identification.
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*
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* Drivers must assume that the clock source is not enabled.
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*
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* clk_get_sys should not be called from within interrupt context.
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*/
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struct clk *clk_get_sys(const char *dev_id, const char *con_id);
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/**
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* clk_add_alias - add a new clock alias
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* @alias: name for clock alias
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* @alias_dev_name: device name
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* @id: platform specific clock name
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* @dev: device
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*
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* Allows using generic clock names for drivers by adding a new alias.
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* Assumes clkdev, see clkdev.h for more info.
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*/
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int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
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struct device *dev);
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#endif
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