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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> | |
eff607fd | 17 | #include <linux/module.h> |
ce26c5bb MH |
18 | #include "governor.h" |
19 | ||
20 | struct userspace_data { | |
21 | unsigned long user_frequency; | |
22 | bool valid; | |
23 | }; | |
24 | ||
25 | static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) | |
26 | { | |
27 | struct userspace_data *data = df->data; | |
28 | ||
6530b9de MH |
29 | if (data->valid) { |
30 | unsigned long adjusted_freq = data->user_frequency; | |
31 | ||
32 | if (df->max_freq && adjusted_freq > df->max_freq) | |
33 | adjusted_freq = df->max_freq; | |
34 | ||
35 | if (df->min_freq && adjusted_freq < df->min_freq) | |
36 | adjusted_freq = df->min_freq; | |
37 | ||
38 | *freq = adjusted_freq; | |
39 | } else { | |
ce26c5bb | 40 | *freq = df->previous_freq; /* No user freq specified yet */ |
6530b9de | 41 | } |
ce26c5bb MH |
42 | return 0; |
43 | } | |
44 | ||
45 | static ssize_t store_freq(struct device *dev, struct device_attribute *attr, | |
46 | const char *buf, size_t count) | |
47 | { | |
48 | struct devfreq *devfreq = to_devfreq(dev); | |
49 | struct userspace_data *data; | |
50 | unsigned long wanted; | |
51 | int err = 0; | |
52 | ||
53 | ||
54 | mutex_lock(&devfreq->lock); | |
55 | data = devfreq->data; | |
56 | ||
57 | sscanf(buf, "%lu", &wanted); | |
58 | data->user_frequency = wanted; | |
59 | data->valid = true; | |
60 | err = update_devfreq(devfreq); | |
61 | if (err == 0) | |
62 | err = count; | |
63 | mutex_unlock(&devfreq->lock); | |
64 | return err; | |
65 | } | |
66 | ||
67 | static ssize_t show_freq(struct device *dev, struct device_attribute *attr, | |
68 | char *buf) | |
69 | { | |
70 | struct devfreq *devfreq = to_devfreq(dev); | |
71 | struct userspace_data *data; | |
72 | int err = 0; | |
73 | ||
74 | mutex_lock(&devfreq->lock); | |
75 | data = devfreq->data; | |
76 | ||
77 | if (data->valid) | |
78 | err = sprintf(buf, "%lu\n", data->user_frequency); | |
79 | else | |
80 | err = sprintf(buf, "undefined\n"); | |
81 | mutex_unlock(&devfreq->lock); | |
82 | return err; | |
83 | } | |
84 | ||
85 | static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq); | |
86 | static struct attribute *dev_entries[] = { | |
87 | &dev_attr_set_freq.attr, | |
88 | NULL, | |
89 | }; | |
90 | static struct attribute_group dev_attr_group = { | |
91 | .name = "userspace", | |
92 | .attrs = dev_entries, | |
93 | }; | |
94 | ||
95 | static int userspace_init(struct devfreq *devfreq) | |
96 | { | |
97 | int err = 0; | |
98 | struct userspace_data *data = kzalloc(sizeof(struct userspace_data), | |
99 | GFP_KERNEL); | |
100 | ||
101 | if (!data) { | |
102 | err = -ENOMEM; | |
103 | goto out; | |
104 | } | |
105 | data->valid = false; | |
106 | devfreq->data = data; | |
107 | ||
108 | err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); | |
109 | out: | |
110 | return err; | |
111 | } | |
112 | ||
113 | static void userspace_exit(struct devfreq *devfreq) | |
114 | { | |
115 | sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); | |
116 | kfree(devfreq->data); | |
117 | devfreq->data = NULL; | |
118 | } | |
119 | ||
7e6fdd4b RV |
120 | static int devfreq_userspace_handler(struct devfreq *devfreq, |
121 | unsigned int event, void *data) | |
122 | { | |
123 | int ret = 0; | |
124 | ||
125 | switch (event) { | |
126 | case DEVFREQ_GOV_START: | |
127 | ret = userspace_init(devfreq); | |
128 | break; | |
129 | case DEVFREQ_GOV_STOP: | |
130 | userspace_exit(devfreq); | |
131 | break; | |
132 | default: | |
133 | break; | |
134 | } | |
135 | ||
136 | return ret; | |
137 | } | |
138 | ||
1b5c1be2 | 139 | static struct devfreq_governor devfreq_userspace = { |
ce26c5bb MH |
140 | .name = "userspace", |
141 | .get_target_freq = devfreq_userspace_func, | |
7e6fdd4b | 142 | .event_handler = devfreq_userspace_handler, |
ce26c5bb | 143 | }; |
83116e66 NM |
144 | |
145 | static int __init devfreq_userspace_init(void) | |
146 | { | |
147 | return devfreq_add_governor(&devfreq_userspace); | |
148 | } | |
149 | subsys_initcall(devfreq_userspace_init); | |
150 | ||
151 | static void __exit devfreq_userspace_exit(void) | |
152 | { | |
153 | int ret; | |
154 | ||
155 | ret = devfreq_remove_governor(&devfreq_userspace); | |
156 | if (ret) | |
157 | pr_err("%s: failed remove governor %d\n", __func__, ret); | |
158 | ||
159 | return; | |
160 | } | |
161 | module_exit(devfreq_userspace_exit); | |
eff607fd | 162 | MODULE_LICENSE("GPL"); |