| MyungJoo Ham | ce26c5b | 2011-10-02 00:19:34 +0200 | [diff] [blame] | 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 | }; |