Merge master.kernel.org:/home/rmk/linux-2.6-i2c manually
[linux-2.6] / arch / arm / plat-omap / cpu-omap.c
1 /*
2  *  linux/arch/arm/plat-omap/cpu-omap.c
3  *
4  *  CPU frequency scaling for OMAP
5  *
6  *  Copyright (C) 2005 Nokia Corporation
7  *  Written by Tony Lindgren <tony@atomide.com>
8  *
9  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/cpufreq.h>
19 #include <linux/delay.h>
20 #include <linux/init.h>
21 #include <linux/err.h>
22
23 #include <asm/hardware.h>
24 #include <asm/mach-types.h>
25 #include <asm/io.h>
26 #include <asm/system.h>
27
28 #include <asm/hardware/clock.h>
29
30 /* TODO: Add support for SDRAM timing changes */
31
32 int omap_verify_speed(struct cpufreq_policy *policy)
33 {
34         struct clk * mpu_clk;
35
36         if (policy->cpu)
37                 return -EINVAL;
38
39         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
40                                      policy->cpuinfo.max_freq);
41         mpu_clk = clk_get(NULL, "mpu");
42         if (IS_ERR(mpu_clk))
43                 return PTR_ERR(mpu_clk);
44         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
45         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
46         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
47                                      policy->cpuinfo.max_freq);
48         clk_put(mpu_clk);
49
50         return 0;
51 }
52
53 unsigned int omap_getspeed(unsigned int cpu)
54 {
55         struct clk * mpu_clk;
56         unsigned long rate;
57
58         if (cpu)
59                 return 0;
60
61         mpu_clk = clk_get(NULL, "mpu");
62         if (IS_ERR(mpu_clk))
63                 return 0;
64         rate = clk_get_rate(mpu_clk) / 1000;
65         clk_put(mpu_clk);
66
67         return rate;
68 }
69
70 static int omap_target(struct cpufreq_policy *policy,
71                        unsigned int target_freq,
72                        unsigned int relation)
73 {
74         struct clk * mpu_clk;
75         struct cpufreq_freqs freqs;
76         int ret = 0;
77
78         mpu_clk = clk_get(NULL, "mpu");
79         if (IS_ERR(mpu_clk))
80                 return PTR_ERR(mpu_clk);
81
82         freqs.old = omap_getspeed(0);
83         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
84         freqs.cpu = 0;
85
86         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
87         ret = clk_set_rate(mpu_clk, target_freq * 1000);
88         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
89         clk_put(mpu_clk);
90
91         return ret;
92 }
93
94 static int __init omap_cpu_init(struct cpufreq_policy *policy)
95 {
96         struct clk * mpu_clk;
97
98         mpu_clk = clk_get(NULL, "mpu");
99         if (IS_ERR(mpu_clk))
100                 return PTR_ERR(mpu_clk);
101
102         if (policy->cpu != 0)
103                 return -EINVAL;
104         policy->cur = policy->min = policy->max = omap_getspeed(0);
105         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
106         policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
107         policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000;
108         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
109         clk_put(mpu_clk);
110
111         return 0;
112 }
113
114 static struct cpufreq_driver omap_driver = {
115         .flags          = CPUFREQ_STICKY,
116         .verify         = omap_verify_speed,
117         .target         = omap_target,
118         .get            = omap_getspeed,
119         .init           = omap_cpu_init,
120         .name           = "omap",
121 };
122
123 static int __init omap_cpufreq_init(void)
124 {
125         return cpufreq_register_driver(&omap_driver);
126 }
127
128 arch_initcall(omap_cpufreq_init);