diff options
Diffstat (limited to 'drivers/devfreq/governor_userspace.c')
| -rw-r--r-- | drivers/devfreq/governor_userspace.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c new file mode 100644 index 000000000..080607c3f --- /dev/null +++ b/drivers/devfreq/governor_userspace.c @@ -0,0 +1,167 @@ +/* + * linux/drivers/devfreq/governor_userspace.c + * + * Copyright (C) 2011 Samsung Electronics + * MyungJoo Ham <myungjoo.ham@samsung.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/slab.h> +#include <linux/device.h> +#include <linux/devfreq.h> +#include <linux/pm.h> +#include <linux/mutex.h> +#include <linux/module.h> +#include "governor.h" + +struct userspace_data { + unsigned long user_frequency; + bool valid; +}; + +static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) +{ + struct userspace_data *data = df->data; + + if (data->valid) { + unsigned long adjusted_freq = data->user_frequency; + + if (df->max_freq && adjusted_freq > df->max_freq) + adjusted_freq = df->max_freq; + + if (df->min_freq && adjusted_freq < df->min_freq) + adjusted_freq = df->min_freq; + + *freq = adjusted_freq; + } else { + *freq = df->previous_freq; /* No user freq specified yet */ + } + return 0; +} + +static ssize_t store_freq(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *devfreq = to_devfreq(dev); + struct userspace_data *data; + unsigned long wanted; + int err = 0; + + mutex_lock(&devfreq->lock); + data = devfreq->data; + + sscanf(buf, "%lu", &wanted); + data->user_frequency = wanted; + data->valid = true; + err = update_devfreq(devfreq); + if (err == 0) + err = count; + mutex_unlock(&devfreq->lock); + return err; +} + +static ssize_t show_freq(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct devfreq *devfreq = to_devfreq(dev); + struct userspace_data *data; + int err = 0; + + mutex_lock(&devfreq->lock); + data = devfreq->data; + + if (data->valid) + err = sprintf(buf, "%lu\n", data->user_frequency); + else + err = sprintf(buf, "undefined\n"); + mutex_unlock(&devfreq->lock); + return err; +} + +static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq); +static struct attribute *dev_entries[] = { + &dev_attr_set_freq.attr, + NULL, +}; +static const struct attribute_group dev_attr_group = { + .name = DEVFREQ_GOV_USERSPACE, + .attrs = dev_entries, +}; + +static int userspace_init(struct devfreq *devfreq) +{ + int err = 0; + struct userspace_data *data = kzalloc(sizeof(struct userspace_data), + GFP_KERNEL); + + if (!data) { + err = -ENOMEM; + goto out; + } + data->valid = false; + devfreq->data = data; + + err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); +out: + return err; +} + +static void userspace_exit(struct devfreq *devfreq) +{ + /* + * Remove the sysfs entry, unless this is being called after + * device_del(), which should have done this already via kobject_del(). + */ + if (devfreq->dev.kobj.sd) + sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); + + kfree(devfreq->data); + devfreq->data = NULL; +} + +static int devfreq_userspace_handler(struct devfreq *devfreq, + unsigned int event, void *data) +{ + int ret = 0; + + switch (event) { + case DEVFREQ_GOV_START: + ret = userspace_init(devfreq); + break; + case DEVFREQ_GOV_STOP: + userspace_exit(devfreq); + break; + default: + break; + } + + return ret; +} + +static struct devfreq_governor devfreq_userspace = { + .name = "userspace", + .get_target_freq = devfreq_userspace_func, + .event_handler = devfreq_userspace_handler, +}; + +static int __init devfreq_userspace_init(void) +{ + return devfreq_add_governor(&devfreq_userspace); +} +subsys_initcall(devfreq_userspace_init); + +static void __exit devfreq_userspace_exit(void) +{ + int ret; + + ret = devfreq_remove_governor(&devfreq_userspace); + if (ret) + pr_err("%s: failed remove governor %d\n", __func__, ret); + + return; +} +module_exit(devfreq_userspace_exit); +MODULE_LICENSE("GPL"); |