Linux Kernel  3.7.1
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clksel.c
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1 /*
2  * linux/arch/arm/mach-w90x900/clksel.c
3  *
4  * Copyright (c) 2008 Nuvoton technology corporation
5  *
6  * Wan ZongShun <[email protected]>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation;version 2 of the License.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/device.h>
16 #include <linux/list.h>
17 #include <linux/errno.h>
18 #include <linux/err.h>
19 #include <linux/string.h>
20 #include <linux/clk.h>
21 #include <linux/mutex.h>
22 #include <linux/io.h>
23 
24 #include <mach/hardware.h>
25 #include <mach/regs-clock.h>
26 
27 #define PLL0 0x00
28 #define PLL1 0x01
29 #define OTHER 0x02
30 #define EXT 0x03
31 #define MSOFFSET 0x0C
32 #define ATAOFFSET 0x0a
33 #define LCDOFFSET 0x06
34 #define AUDOFFSET 0x04
35 #define CPUOFFSET 0x00
36 
37 static DEFINE_MUTEX(clksel_sem);
38 
39 static void clock_source_select(const char *dev_id, unsigned int clkval)
40 {
41  unsigned int clksel, offset;
42 
43  clksel = __raw_readl(REG_CLKSEL);
44 
45  if (strcmp(dev_id, "nuc900-ms") == 0)
46  offset = MSOFFSET;
47  else if (strcmp(dev_id, "nuc900-atapi") == 0)
48  offset = ATAOFFSET;
49  else if (strcmp(dev_id, "nuc900-lcd") == 0)
50  offset = LCDOFFSET;
51  else if (strcmp(dev_id, "nuc900-ac97") == 0)
52  offset = AUDOFFSET;
53  else
54  offset = CPUOFFSET;
55 
56  clksel &= ~(0x03 << offset);
57  clksel |= (clkval << offset);
58 
59  __raw_writel(clksel, REG_CLKSEL);
60 }
61 
62 void nuc900_clock_source(struct device *dev, unsigned char *src)
63 {
64  unsigned int clkval;
65  const char *dev_id;
66 
67  BUG_ON(!src);
68  clkval = 0;
69 
70  mutex_lock(&clksel_sem);
71 
72  if (dev)
73  dev_id = dev_name(dev);
74  else
75  dev_id = "cpufreq";
76 
77  if (strcmp(src, "pll0") == 0)
78  clkval = PLL0;
79  else if (strcmp(src, "pll1") == 0)
80  clkval = PLL1;
81  else if (strcmp(src, "ext") == 0)
82  clkval = EXT;
83  else if (strcmp(src, "oth") == 0)
84  clkval = OTHER;
85 
86  clock_source_select(dev_id, clkval);
87 
88  mutex_unlock(&clksel_sem);
89 }
91