Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
[linux-2.6.git] / drivers / macintosh / windfarm_cpufreq_clamp.c
1 #include <linux/types.h>
2 #include <linux/errno.h>
3 #include <linux/kernel.h>
4 #include <linux/delay.h>
5 #include <linux/slab.h>
6 #include <linux/init.h>
7 #include <linux/wait.h>
8 #include <linux/cpufreq.h>
9
10 #include <asm/prom.h>
11
12 #include "windfarm.h"
13
14 #define VERSION "0.3"
15
16 static int clamped;
17 static struct wf_control *clamp_control;
18
19 static int clamp_notifier_call(struct notifier_block *self,
20                                unsigned long event, void *data)
21 {
22         struct cpufreq_policy *p = data;
23         unsigned long max_freq;
24
25         if (event != CPUFREQ_ADJUST)
26                 return 0;
27
28         max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
29         cpufreq_verify_within_limits(p, 0, max_freq);
30
31         return 0;
32 }
33
34 static struct notifier_block clamp_notifier = {
35         .notifier_call = clamp_notifier_call,
36 };
37
38 static int clamp_set(struct wf_control *ct, s32 value)
39 {
40         if (value)
41                 printk(KERN_INFO "windfarm: Clamping CPU frequency to "
42                        "minimum !\n");
43         else
44                 printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
45         clamped = value;
46         cpufreq_update_policy(0);
47         return 0;
48 }
49
50 static int clamp_get(struct wf_control *ct, s32 *value)
51 {
52         *value = clamped;
53         return 0;
54 }
55
56 static s32 clamp_min(struct wf_control *ct)
57 {
58         return 0;
59 }
60
61 static s32 clamp_max(struct wf_control *ct)
62 {
63         return 1;
64 }
65
66 static struct wf_control_ops clamp_ops = {
67         .set_value      = clamp_set,
68         .get_value      = clamp_get,
69         .get_min        = clamp_min,
70         .get_max        = clamp_max,
71         .owner          = THIS_MODULE,
72 };
73
74 static int __init wf_cpufreq_clamp_init(void)
75 {
76         struct wf_control *clamp;
77
78         /* Don't register on old machines that use therm_pm72 for now */
79         if (of_machine_is_compatible("PowerMac7,2") ||
80             of_machine_is_compatible("PowerMac7,3") ||
81             of_machine_is_compatible("RackMac3,1"))
82                 return -ENODEV;
83
84         clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
85         if (clamp == NULL)
86                 return -ENOMEM;
87         cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
88         clamp->ops = &clamp_ops;
89         clamp->name = "cpufreq-clamp";
90         if (wf_register_control(clamp))
91                 goto fail;
92         clamp_control = clamp;
93         return 0;
94  fail:
95         kfree(clamp);
96         return -ENODEV;
97 }
98
99 static void __exit wf_cpufreq_clamp_exit(void)
100 {
101         if (clamp_control)
102                 wf_unregister_control(clamp_control);
103 }
104
105
106 module_init(wf_cpufreq_clamp_init);
107 module_exit(wf_cpufreq_clamp_exit);
108
109 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
110 MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
111 MODULE_LICENSE("GPL");
112