2 * Clock framework for Telechips SoCs
3 * Based on arch/arm/plat-mxc/clock.c
5 * Copyright (C) 2004 - 2005 Nokia corporation
6 * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
7 * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
8 * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
9 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
10 * Copyright 2010 Hans J. Koch, hjk@linutronix.de
12 * Licensed under the terms of the GPL v2.
15 #include <linux/clk.h>
16 #include <linux/err.h>
17 #include <linux/errno.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
20 #include <linux/string.h>
22 #include <mach/clock.h>
23 #include <mach/hardware.h>
25 static DEFINE_MUTEX(clocks_mutex
);
27 /*-------------------------------------------------------------------------
28 * Standard clock functions defined in include/linux/clk.h
29 *-------------------------------------------------------------------------*/
31 static void __clk_disable(struct clk
*clk
)
33 BUG_ON(clk
->refcount
== 0);
35 if (!(--clk
->refcount
) && clk
->disable
) {
36 /* Unconditionally disable the clock in hardware */
38 /* recursively disable parents */
40 __clk_disable(clk
->parent
);
44 static int __clk_enable(struct clk
*clk
)
48 if (clk
->refcount
++ == 0 && clk
->enable
) {
50 ret
= __clk_enable(clk
->parent
);
54 return clk
->enable(clk
);
60 /* This function increments the reference count on the clock and enables the
61 * clock if not already enabled. The parent clock tree is recursively enabled
63 int clk_enable(struct clk
*clk
)
70 mutex_lock(&clocks_mutex
);
71 ret
= __clk_enable(clk
);
72 mutex_unlock(&clocks_mutex
);
76 EXPORT_SYMBOL_GPL(clk_enable
);
78 /* This function decrements the reference count on the clock and disables
79 * the clock when reference count is 0. The parent clock tree is
80 * recursively disabled
82 void clk_disable(struct clk
*clk
)
87 mutex_lock(&clocks_mutex
);
89 mutex_unlock(&clocks_mutex
);
91 EXPORT_SYMBOL_GPL(clk_disable
);
93 /* Retrieve the *current* clock rate. If the clock itself
94 * does not provide a special calculation routine, ask
95 * its parent and so on, until one is able to return
98 unsigned long clk_get_rate(struct clk
*clk
)
104 return clk
->get_rate(clk
);
106 return clk_get_rate(clk
->parent
);
108 EXPORT_SYMBOL_GPL(clk_get_rate
);
110 /* Round the requested clock rate to the nearest supported
111 * rate that is less than or equal to the requested rate.
112 * This is dependent on the clock's current parent.
114 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
118 if (!clk
->round_rate
)
121 return clk
->round_rate(clk
, rate
);
123 EXPORT_SYMBOL_GPL(clk_round_rate
);
125 /* Set the clock to the requested clock rate. The rate must
126 * match a supported rate exactly based on what clk_round_rate returns
128 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
134 if (!clk
->set_rate
|| !rate
)
137 mutex_lock(&clocks_mutex
);
138 ret
= clk
->set_rate(clk
, rate
);
139 mutex_unlock(&clocks_mutex
);
143 EXPORT_SYMBOL_GPL(clk_set_rate
);
145 /* Set the clock's parent to another clock source */
146 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
153 if (!clk
->set_parent
|| !parent
)
156 mutex_lock(&clocks_mutex
);
159 __clk_enable(parent
);
160 ret
= clk
->set_parent(clk
, parent
);
165 mutex_unlock(&clocks_mutex
);
169 EXPORT_SYMBOL_GPL(clk_set_parent
);
171 /* Retrieve the clock's parent clock source */
172 struct clk
*clk_get_parent(struct clk
*clk
)
179 EXPORT_SYMBOL_GPL(clk_get_parent
);
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