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 devfreq_userspace_func(struct devfreq * df,unsigned long * freq)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 unsigned long adjusted_freq = data->user_frequency; 30 31 if (df->max_freq && adjusted_freq > df->max_freq) 32 adjusted_freq = df->max_freq; 33 34 if (df->min_freq && adjusted_freq < df->min_freq) 35 adjusted_freq = df->min_freq; 36 37 *freq = adjusted_freq; 38 } else { 39 *freq = df->previous_freq; /* No user freq specified yet */ 40 } 41 return 0; 42 } 43 store_freq(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)44 static ssize_t store_freq(struct device *dev, struct device_attribute *attr, 45 const char *buf, size_t count) 46 { 47 struct devfreq *devfreq = to_devfreq(dev); 48 struct userspace_data *data; 49 unsigned long wanted; 50 int err = 0; 51 52 53 mutex_lock(&devfreq->lock); 54 data = devfreq->data; 55 56 sscanf(buf, "%lu", &wanted); 57 data->user_frequency = wanted; 58 data->valid = true; 59 err = update_devfreq(devfreq); 60 if (err == 0) 61 err = count; 62 mutex_unlock(&devfreq->lock); 63 return err; 64 } 65 show_freq(struct device * dev,struct device_attribute * attr,char * buf)66 static ssize_t show_freq(struct device *dev, struct device_attribute *attr, 67 char *buf) 68 { 69 struct devfreq *devfreq = to_devfreq(dev); 70 struct userspace_data *data; 71 int err = 0; 72 73 mutex_lock(&devfreq->lock); 74 data = devfreq->data; 75 76 if (data->valid) 77 err = sprintf(buf, "%lu\n", data->user_frequency); 78 else 79 err = sprintf(buf, "undefined\n"); 80 mutex_unlock(&devfreq->lock); 81 return err; 82 } 83 84 static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq); 85 static struct attribute *dev_entries[] = { 86 &dev_attr_set_freq.attr, 87 NULL, 88 }; 89 static struct attribute_group dev_attr_group = { 90 .name = "userspace", 91 .attrs = dev_entries, 92 }; 93 userspace_init(struct devfreq * devfreq)94 static int userspace_init(struct devfreq *devfreq) 95 { 96 int err = 0; 97 struct userspace_data *data = kzalloc(sizeof(struct userspace_data), 98 GFP_KERNEL); 99 100 if (!data) { 101 err = -ENOMEM; 102 goto out; 103 } 104 data->valid = false; 105 devfreq->data = data; 106 107 err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); 108 out: 109 return err; 110 } 111 userspace_exit(struct devfreq * devfreq)112 static void userspace_exit(struct devfreq *devfreq) 113 { 114 sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); 115 kfree(devfreq->data); 116 devfreq->data = NULL; 117 } 118 119 const struct devfreq_governor devfreq_userspace = { 120 .name = "userspace", 121 .get_target_freq = devfreq_userspace_func, 122 .init = userspace_init, 123 .exit = userspace_exit, 124 .no_central_polling = true, 125 }; 126