1 /* 2 * linux/drivers/devfreq/governor_powersave.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/devfreq.h> 13 #include <linux/module.h> 14 #include "governor.h" 15 16 static int devfreq_powersave_func(struct devfreq *df, 17 unsigned long *freq) 18 { 19 /* 20 * target callback should be able to get ceiling value as 21 * said in devfreq.h 22 */ 23 *freq = DEVFREQ_MIN_FREQ; 24 return 0; 25 } 26 27 static int devfreq_powersave_handler(struct devfreq *devfreq, 28 unsigned int event, void *data) 29 { 30 int ret = 0; 31 32 if (event == DEVFREQ_GOV_START) { 33 mutex_lock(&devfreq->lock); 34 ret = update_devfreq(devfreq); 35 mutex_unlock(&devfreq->lock); 36 } 37 38 return ret; 39 } 40 41 static struct devfreq_governor devfreq_powersave = { 42 .name = DEVFREQ_GOV_POWERSAVE, 43 .get_target_freq = devfreq_powersave_func, 44 .event_handler = devfreq_powersave_handler, 45 }; 46 47 static int __init devfreq_powersave_init(void) 48 { 49 return devfreq_add_governor(&devfreq_powersave); 50 } 51 subsys_initcall(devfreq_powersave_init); 52 53 static void __exit devfreq_powersave_exit(void) 54 { 55 int ret; 56 57 ret = devfreq_remove_governor(&devfreq_powersave); 58 if (ret) 59 pr_err("%s: failed remove governor %d\n", __func__, ret); 60 61 return; 62 } 63 module_exit(devfreq_powersave_exit); 64 MODULE_LICENSE("GPL"); 65