Merge branch 'drm-forlinus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[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 #include <linux/clk.h>
23
24 #include <asm/hardware.h>
25 #include <asm/io.h>
26 #include <asm/system.h>
27
28 /* TODO: Add support for SDRAM timing changes */
29
30 int omap_verify_speed(struct cpufreq_policy *policy)
31 {
32         struct clk * mpu_clk;
33
34         if (policy->cpu)
35                 return -EINVAL;
36
37         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
38                                      policy->cpuinfo.max_freq);
39         mpu_clk = clk_get(NULL, "mpu");
40         if (IS_ERR(mpu_clk))
41                 return PTR_ERR(mpu_clk);
42         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
43         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
44         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
45                                      policy->cpuinfo.max_freq);
46         clk_put(mpu_clk);
47
48         return 0;
49 }
50
51 unsigned int omap_getspeed(unsigned int cpu)
52 {
53         struct clk * mpu_clk;
54         unsigned long rate;
55
56         if (cpu)
57                 return 0;
58
59         mpu_clk = clk_get(NULL, "mpu");
60         if (IS_ERR(mpu_clk))
61                 return 0;
62         rate = clk_get_rate(mpu_clk) / 1000;
63         clk_put(mpu_clk);
64
65         return rate;
66 }
67
68 static int omap_target(struct cpufreq_policy *policy,
69                        unsigned int target_freq,
70                        unsigned int relation)
71 {
72         struct clk * mpu_clk;
73         struct cpufreq_freqs freqs;
74         int ret = 0;
75
76         mpu_clk = clk_get(NULL, "mpu");
77         if (IS_ERR(mpu_clk))
78                 return PTR_ERR(mpu_clk);
79
80         freqs.old = omap_getspeed(0);
81         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
82         freqs.cpu = 0;
83
84         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
85         ret = clk_set_rate(mpu_clk, target_freq * 1000);
86         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
87         clk_put(mpu_clk);
88
89         return ret;
90 }
91
92 static int __init omap_cpu_init(struct cpufreq_policy *policy)
93 {
94         struct clk * mpu_clk;
95
96         mpu_clk = clk_get(NULL, "mpu");
97         if (IS_ERR(mpu_clk))
98                 return PTR_ERR(mpu_clk);
99
100         if (policy->cpu != 0)
101                 return -EINVAL;
102         policy->cur = policy->min = policy->max = omap_getspeed(0);
103         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
104         policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
105         policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 216000000) / 1000;
106         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
107         clk_put(mpu_clk);
108
109         return 0;
110 }
111
112 static struct cpufreq_driver omap_driver = {
113         .flags          = CPUFREQ_STICKY,
114         .verify         = omap_verify_speed,
115         .target         = omap_target,
116         .get            = omap_getspeed,
117         .init           = omap_cpu_init,
118         .name           = "omap",
119 };
120
121 static int __init omap_cpufreq_init(void)
122 {
123         return cpufreq_register_driver(&omap_driver);
124 }
125
126 arch_initcall(omap_cpufreq_init);