Root/arch/arm/mach-w90x900/clksel.c

1/*
2 * linux/arch/arm/mach-w90x900/clksel.c
3 *
4 * Copyright (c) 2008 Nuvoton technology corporation
5 *
6 * Wan ZongShun <mcuos.com@gmail.com>
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
37static DEFINE_MUTEX(clksel_sem);
38
39static 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-audio") == 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
62void 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}
90EXPORT_SYMBOL(nuc900_clock_source);
91
92

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