2 * Based on arch/arm/plat-omap/clock.c
4 * Copyright (C) 2004 - 2005 Nokia corporation
5 * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
6 * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
7 * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
8 * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
27 #include <linux/clk.h>
28 #include <linux/err.h>
29 #include <linux/errno.h>
30 #include <linux/init.h>
32 #include <linux/kernel.h>
33 #include <linux/list.h>
34 #include <linux/module.h>
35 #include <linux/mutex.h>
36 #include <linux/platform_device.h>
37 #include <linux/proc_fs.h>
38 #include <linux/semaphore.h>
39 #include <linux/string.h>
41 #include <mach/clock.h>
42 #include <mach/hardware.h>
44 static LIST_HEAD(clocks
);
45 static DEFINE_MUTEX(clocks_mutex
);
47 /*-------------------------------------------------------------------------
48 * Standard clock functions defined in include/linux/clk.h
49 *-------------------------------------------------------------------------*/
51 static void __clk_disable(struct clk
*clk
)
53 if (clk
== NULL
|| IS_ERR(clk
))
55 WARN_ON(!clk
->usecount
);
57 if (!(--clk
->usecount
)) {
60 __clk_disable(clk
->parent
);
61 __clk_disable(clk
->secondary
);
65 static int __clk_enable(struct clk
*clk
)
67 if (clk
== NULL
|| IS_ERR(clk
))
70 if (clk
->usecount
++ == 0) {
71 __clk_enable(clk
->parent
);
72 __clk_enable(clk
->secondary
);
80 /* This function increments the reference count on the clock and enables the
81 * clock if not already enabled. The parent clock tree is recursively enabled
83 int clk_enable(struct clk
*clk
)
87 if (clk
== NULL
|| IS_ERR(clk
))
90 mutex_lock(&clocks_mutex
);
91 ret
= __clk_enable(clk
);
92 mutex_unlock(&clocks_mutex
);
96 EXPORT_SYMBOL(clk_enable
);
98 /* This function decrements the reference count on the clock and disables
99 * the clock when reference count is 0. The parent clock tree is
100 * recursively disabled
102 void clk_disable(struct clk
*clk
)
104 if (clk
== NULL
|| IS_ERR(clk
))
107 mutex_lock(&clocks_mutex
);
109 mutex_unlock(&clocks_mutex
);
111 EXPORT_SYMBOL(clk_disable
);
113 /* Retrieve the *current* clock rate. If the clock itself
114 * does not provide a special calculation routine, ask
115 * its parent and so on, until one is able to return
118 unsigned long clk_get_rate(struct clk
*clk
)
120 if (clk
== NULL
|| IS_ERR(clk
))
124 return clk
->get_rate(clk
);
126 return clk_get_rate(clk
->parent
);
128 EXPORT_SYMBOL(clk_get_rate
);
130 /* Round the requested clock rate to the nearest supported
131 * rate that is less than or equal to the requested rate.
132 * This is dependent on the clock's current parent.
134 long clk_round_rate(struct clk
*clk
, unsigned long rate
)
136 if (clk
== NULL
|| IS_ERR(clk
) || !clk
->round_rate
)
139 return clk
->round_rate(clk
, rate
);
141 EXPORT_SYMBOL(clk_round_rate
);
143 /* Set the clock to the requested clock rate. The rate must
144 * match a supported rate exactly based on what clk_round_rate returns
146 int clk_set_rate(struct clk
*clk
, unsigned long rate
)
150 if (clk
== NULL
|| IS_ERR(clk
) || clk
->set_rate
== NULL
|| rate
== 0)
153 mutex_lock(&clocks_mutex
);
154 ret
= clk
->set_rate(clk
, rate
);
155 mutex_unlock(&clocks_mutex
);
159 EXPORT_SYMBOL(clk_set_rate
);
161 /* Set the clock's parent to another clock source */
162 int clk_set_parent(struct clk
*clk
, struct clk
*parent
)
167 if (clk
== NULL
|| IS_ERR(clk
) || parent
== NULL
||
168 IS_ERR(parent
) || clk
->set_parent
== NULL
)
174 mutex_lock(&clocks_mutex
);
175 ret
= clk
->set_parent(clk
, parent
);
178 clk
->parent
= parent
;
182 mutex_unlock(&clocks_mutex
);
189 EXPORT_SYMBOL(clk_set_parent
);
191 /* Retrieve the clock's parent clock source */
192 struct clk
*clk_get_parent(struct clk
*clk
)
194 struct clk
*ret
= NULL
;
196 if (clk
== NULL
|| IS_ERR(clk
))
201 EXPORT_SYMBOL(clk_get_parent
);
204 * Get the resulting clock rate from a PLL register value and the input
205 * frequency. PLLs with this register layout can at least be found on
206 * MX1, MX21, MX27 and MX31
208 * mfi + mfn / (mfd + 1)
209 * f = 2 * f_ref * --------------------
212 unsigned long mxc_decode_pll(unsigned int reg_val
, u32 freq
)
216 unsigned int mfi
, mfn
, mfd
, pd
;
218 mfi
= (reg_val
>> 10) & 0xf;
219 mfn
= reg_val
& 0x3ff;
220 mfd
= (reg_val
>> 16) & 0x3ff;
221 pd
= (reg_val
>> 26) & 0xf;
223 mfi
= mfi
<= 5 ? 5 : mfi
;
227 /* On all i.MXs except i.MX1 and i.MX21 mfn is a 10bit
228 * 2's complements number
230 if (!cpu_is_mx1() && !cpu_is_mx21() && mfn
>= 0x200)
231 mfn_abs
= 0x400 - mfn
;
236 ll
= (unsigned long long)freq
* mfn_abs
;
240 if (!cpu_is_mx1() && !cpu_is_mx21() && mfn
>= 0x200)
243 ll
= (freq
* mfi
) + ll
;
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