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ce26c5bb MH |
1 | /* |
2 | * linux/drivers/devfreq/governor_simpleondemand.c | |
3 | * | |
4 | * Copyright (C) 2011 Samsung Electronics | |
5 | * MyungJoo Ham <myungjoo.ham@samsung.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/slab.h> | |
13 | #include <linux/device.h> | |
14 | #include <linux/devfreq.h> | |
15 | #include <linux/pm.h> | |
16 | #include <linux/mutex.h> | |
17 | #include "governor.h" | |
18 | ||
19 | struct userspace_data { | |
20 | unsigned long user_frequency; | |
21 | bool valid; | |
22 | }; | |
23 | ||
24 | static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) | |
25 | { | |
26 | struct userspace_data *data = df->data; | |
27 | ||
28 | if (!data->valid) | |
29 | *freq = df->previous_freq; /* No user freq specified yet */ | |
30 | else | |
31 | *freq = data->user_frequency; | |
32 | return 0; | |
33 | } | |
34 | ||
35 | static ssize_t store_freq(struct device *dev, struct device_attribute *attr, | |
36 | const char *buf, size_t count) | |
37 | { | |
38 | struct devfreq *devfreq = to_devfreq(dev); | |
39 | struct userspace_data *data; | |
40 | unsigned long wanted; | |
41 | int err = 0; | |
42 | ||
43 | ||
44 | mutex_lock(&devfreq->lock); | |
45 | data = devfreq->data; | |
46 | ||
47 | sscanf(buf, "%lu", &wanted); | |
48 | data->user_frequency = wanted; | |
49 | data->valid = true; | |
50 | err = update_devfreq(devfreq); | |
51 | if (err == 0) | |
52 | err = count; | |
53 | mutex_unlock(&devfreq->lock); | |
54 | return err; | |
55 | } | |
56 | ||
57 | static ssize_t show_freq(struct device *dev, struct device_attribute *attr, | |
58 | char *buf) | |
59 | { | |
60 | struct devfreq *devfreq = to_devfreq(dev); | |
61 | struct userspace_data *data; | |
62 | int err = 0; | |
63 | ||
64 | mutex_lock(&devfreq->lock); | |
65 | data = devfreq->data; | |
66 | ||
67 | if (data->valid) | |
68 | err = sprintf(buf, "%lu\n", data->user_frequency); | |
69 | else | |
70 | err = sprintf(buf, "undefined\n"); | |
71 | mutex_unlock(&devfreq->lock); | |
72 | return err; | |
73 | } | |
74 | ||
75 | static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq); | |
76 | static struct attribute *dev_entries[] = { | |
77 | &dev_attr_set_freq.attr, | |
78 | NULL, | |
79 | }; | |
80 | static struct attribute_group dev_attr_group = { | |
81 | .name = "userspace", | |
82 | .attrs = dev_entries, | |
83 | }; | |
84 | ||
85 | static int userspace_init(struct devfreq *devfreq) | |
86 | { | |
87 | int err = 0; | |
88 | struct userspace_data *data = kzalloc(sizeof(struct userspace_data), | |
89 | GFP_KERNEL); | |
90 | ||
91 | if (!data) { | |
92 | err = -ENOMEM; | |
93 | goto out; | |
94 | } | |
95 | data->valid = false; | |
96 | devfreq->data = data; | |
97 | ||
98 | err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); | |
99 | out: | |
100 | return err; | |
101 | } | |
102 | ||
103 | static void userspace_exit(struct devfreq *devfreq) | |
104 | { | |
105 | sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); | |
106 | kfree(devfreq->data); | |
107 | devfreq->data = NULL; | |
108 | } | |
109 | ||
110 | const struct devfreq_governor devfreq_userspace = { | |
111 | .name = "userspace", | |
112 | .get_target_freq = devfreq_userspace_func, | |
113 | .init = userspace_init, | |
114 | .exit = userspace_exit, | |
115 | .no_central_polling = true, | |
116 | }; |