Merge master.kernel.org:/home/rmk/linux-2.6-drvmodel
[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/io.h>
25 #include <asm/system.h>
26
27 #include <asm/hardware/clock.h>
28
29 /* TODO: Add support for SDRAM timing changes */
30
31 int omap_verify_speed(struct cpufreq_policy *policy)
32 {
33         struct clk * mpu_clk;
34
35         if (policy->cpu)
36                 return -EINVAL;
37
38         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
39                                      policy->cpuinfo.max_freq);
40         mpu_clk = clk_get(NULL, "mpu");
41         if (IS_ERR(mpu_clk))
42                 return PTR_ERR(mpu_clk);
43         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
44         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
45         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
46                                      policy->cpuinfo.max_freq);
47         clk_put(mpu_clk);
48
49         return 0;
50 }
51
52 unsigned int omap_getspeed(unsigned int cpu)
53 {
54         struct clk * mpu_clk;
55         unsigned long rate;
56
57         if (cpu)
58                 return 0;
59
60         mpu_clk = clk_get(NULL, "mpu");
61         if (IS_ERR(mpu_clk))
62                 return 0;
63         rate = clk_get_rate(mpu_clk) / 1000;
64         clk_put(mpu_clk);
65
66         return rate;
67 }
68
69 static int omap_target(struct cpufreq_policy *policy,
70                        unsigned int target_freq,
71                        unsigned int relation)
72 {
73         struct clk * mpu_clk;
74         struct cpufreq_freqs freqs;
75         int ret = 0;
76
77         mpu_clk = clk_get(NULL, "mpu");
78         if (IS_ERR(mpu_clk))
79                 return PTR_ERR(mpu_clk);
80
81         freqs.old = omap_getspeed(0);
82         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
83         freqs.cpu = 0;
84
85         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
86         ret = clk_set_rate(mpu_clk, target_freq * 1000);
87         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
88         clk_put(mpu_clk);
89
90         return ret;
91 }
92
93 static int __init omap_cpu_init(struct cpufreq_policy *policy)
94 {
95         struct clk * mpu_clk;
96
97         mpu_clk = clk_get(NULL, "mpu");
98         if (IS_ERR(mpu_clk))
99                 return PTR_ERR(mpu_clk);
100
101         if (policy->cpu != 0)
102                 return -EINVAL;
103         policy->cur = policy->min = policy->max = omap_getspeed(0);
104         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
105         policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
106         policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000;
107         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
108         clk_put(mpu_clk);
109
110         return 0;
111 }
112
113 static struct cpufreq_driver omap_driver = {
114         .flags          = CPUFREQ_STICKY,
115         .verify         = omap_verify_speed,
116         .target         = omap_target,
117         .get            = omap_getspeed,
118         .init           = omap_cpu_init,
119         .name           = "omap",
120 };
121
122 static int __init omap_cpufreq_init(void)
123 {
124         return cpufreq_register_driver(&omap_driver);
125 }
126
127 arch_initcall(omap_cpufreq_init);