125 lines
3.2 KiB
C
125 lines
3.2 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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*
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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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struct device;
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/*
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* The base API.
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*/
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/*
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* struct clk - an machine class defined object / cookie.
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*/
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struct clk;
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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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struct clk *clk_get(struct device *dev, const char *id);
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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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* 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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* 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_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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void clk_put(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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#endif
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