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| 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 <linux/module.h> |
| 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 | |
| 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 { |
| 40 | *freq = df->previous_freq; /* No user freq specified yet */ |
| 41 | } |
| 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 | |
| 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 | |
| 139 | static struct devfreq_governor devfreq_userspace = { |
| 140 | .name = "userspace", |
| 141 | .get_target_freq = devfreq_userspace_func, |
| 142 | .event_handler = devfreq_userspace_handler, |
| 143 | }; |
| 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); |
| 162 | MODULE_LICENSE("GPL"); |
| 163 |
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