1 /*
2  *  linux/arch/arm/mach-sa1100/clock.c
3  */
4 #include <linux/module.h>
5 #include <linux/kernel.h>
6 #include <linux/device.h>
7 #include <linux/list.h>
8 #include <linux/errno.h>
9 #include <linux/err.h>
10 #include <linux/string.h>
11 #include <linux/clk.h>
12 #include <linux/spinlock.h>
13 #include <linux/mutex.h>
14 
15 #include <mach/hardware.h>
16 
17 /*
18  * Very simple clock implementation - we only have one clock to deal with.
19  */
20 struct clk {
21 	unsigned int		enabled;
22 };
23 
clk_gpio27_enable(void)24 static void clk_gpio27_enable(void)
25 {
26 	/*
27 	 * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
28 	 * (SA-1110 Developer's Manual, section 9.1.2.1)
29 	 */
30 	GAFR |= GPIO_32_768kHz;
31 	GPDR |= GPIO_32_768kHz;
32 	TUCR = TUCR_3_6864MHz;
33 }
34 
clk_gpio27_disable(void)35 static void clk_gpio27_disable(void)
36 {
37 	TUCR = 0;
38 	GPDR &= ~GPIO_32_768kHz;
39 	GAFR &= ~GPIO_32_768kHz;
40 }
41 
42 static struct clk clk_gpio27;
43 
44 static DEFINE_SPINLOCK(clocks_lock);
45 
clk_get(struct device * dev,const char * id)46 struct clk *clk_get(struct device *dev, const char *id)
47 {
48 	const char *devname = dev_name(dev);
49 
50 	return strcmp(devname, "sa1111.0") ? ERR_PTR(-ENOENT) : &clk_gpio27;
51 }
52 EXPORT_SYMBOL(clk_get);
53 
clk_put(struct clk * clk)54 void clk_put(struct clk *clk)
55 {
56 }
57 EXPORT_SYMBOL(clk_put);
58 
clk_enable(struct clk * clk)59 int clk_enable(struct clk *clk)
60 {
61 	unsigned long flags;
62 
63 	spin_lock_irqsave(&clocks_lock, flags);
64 	if (clk->enabled++ == 0)
65 		clk_gpio27_enable();
66 	spin_unlock_irqrestore(&clocks_lock, flags);
67 	return 0;
68 }
69 EXPORT_SYMBOL(clk_enable);
70 
clk_disable(struct clk * clk)71 void clk_disable(struct clk *clk)
72 {
73 	unsigned long flags;
74 
75 	WARN_ON(clk->enabled == 0);
76 
77 	spin_lock_irqsave(&clocks_lock, flags);
78 	if (--clk->enabled == 0)
79 		clk_gpio27_disable();
80 	spin_unlock_irqrestore(&clocks_lock, flags);
81 }
82 EXPORT_SYMBOL(clk_disable);
83 
clk_get_rate(struct clk * clk)84 unsigned long clk_get_rate(struct clk *clk)
85 {
86 	return 3686400;
87 }
88 EXPORT_SYMBOL(clk_get_rate);
89