include/asm-arm/hardware/clock.h

   1 /*
   2  *  linux/include/asm-arm/hardware/clock.h
   3  *
   4  *  Copyright (C) 2004 ARM Limited.
   5  *  Written by Deep Blue Solutions Limited.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #ifndef ASMARM_CLOCK_H
  12 #define ASMARM_CLOCK_H
  13
  14 struct device;
  15
  16 /*
  17  * The base API.
  18  */
  19
  20
  21 /*
  22  * struct clk - an machine class defined object / cookie.
  23  */
  24 struct clk;
  25
  26 /**
  27  * clk_get - lookup and obtain a reference to a clock producer.
  28  * @dev: device for clock "consumer"
  29  * @id: device ID
  30  *
  31  * Returns a struct clk corresponding to the clock producer, or
  32  * valid IS_ERR() condition containing errno.
  33  */
  34 struct clk *clk_get(struct device *dev, const char *id);
  35
  36 /**
  37  * clk_enable - inform the system when the clock source should be running.
  38  * @clk: clock source
  39  *
  40  * If the clock can not be enabled/disabled, this should return success.
  41  *
  42  * Returns success (0) or negative errno.
  43  */
  44 int clk_enable(struct clk *clk);
  45
  46 /**
  47  * clk_disable - inform the system when the clock source is no longer required.
  48  * @clk: clock source
  49  */
  50 void clk_disable(struct clk *clk);
  51
  52 /**
  53  * clk_use - increment the use count
  54  * @clk: clock source
  55  *
  56  * Returns success (0) or negative errno.
  57  */
  58 int clk_use(struct clk *clk);
  59
  60 /**
  61  * clk_unuse - decrement the use count
  62  * @clk: clock source
  63  */
  64 void clk_unuse(struct clk *clk);
  65
  66 /**
  67  * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
  68  *                This is only valid once the clock source has been enabled.
  69  * @clk: clock source
  70  */
  71 unsigned long clk_get_rate(struct clk *clk);
  72
  73 /**
  74  * clk_put      - "free" the clock source
  75  * @clk: clock source
  76  */
  77 void clk_put(struct clk *clk);
  78
  79
  80 /*
  81  * The remaining APIs are optional for machine class support.
  82  */
  83
  84
  85 /**
  86  * clk_round_rate - adjust a rate to the exact rate a clock can provide
  87  * @clk: clock source
  88  * @rate: desired clock rate in Hz
  89  *
  90  * Returns rounded clock rate in Hz, or negative errno.
  91  */
  92 long clk_round_rate(struct clk *clk, unsigned long rate);
  93
  94 /**
  95  * clk_set_rate - set the clock rate for a clock source
  96  * @clk: clock source
  97  * @rate: desired clock rate in Hz
  98  *
  99  * Returns success (0) or negative errno.
 100  */
 101 int clk_set_rate(struct clk *clk, unsigned long rate);
 102
 103 /**
 104  * clk_set_parent - set the parent clock source for this clock
 105  * @clk: clock source
 106  * @parent: parent clock source
 107  *
 108  * Returns success (0) or negative errno.
 109  */
 110 int clk_set_parent(struct clk *clk, struct clk *parent);
 111
 112 /**
 113  * clk_get_parent - get the parent clock source for this clock
 114  * @clk: clock source
 115  *
 116  * Returns struct clk corresponding to parent clock source, or
 117  * valid IS_ERR() condition containing errno.
 118  */
 119 struct clk *clk_get_parent(struct clk *clk);
 120
 121 #endif