alistair23-linux/drivers/cpufreq/cpufreq_powersave.c
Rafael J. Wysocki e788892ba3 cpufreq: governor: Get rid of governor events
The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different code paths for different purposes.  The purpose it is
invoked for is determined by its second "event" argument, causing it
to act as a "callback multiplexer" of sorts.

Unfortunately, that leads to extra complexity in governors, some of
which implement the ->governor() callback as a switch statement
that simply checks the event argument and invokes a separate function
to handle that specific event.

That extra complexity can be eliminated by replacing the all-purpose
->governor() callback with a family of callbacks to carry out specific
governor operations: initialization and exit, start and stop and policy
limits updates.  That also turns out to reduce the code size too, so
do it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-06-02 23:24:15 +02:00

56 lines
1.4 KiB
C

/*
* linux/drivers/cpufreq/cpufreq_powersave.c
*
* Copyright (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
*
*
* 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.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpufreq.h>
#include <linux/init.h>
#include <linux/module.h>
static void cpufreq_gov_powersave_limits(struct cpufreq_policy *policy)
{
pr_debug("setting to %u kHz\n", policy->min);
__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
}
static struct cpufreq_governor cpufreq_gov_powersave = {
.name = "powersave",
.limits = cpufreq_gov_powersave_limits,
.owner = THIS_MODULE,
};
static int __init cpufreq_gov_powersave_init(void)
{
return cpufreq_register_governor(&cpufreq_gov_powersave);
}
static void __exit cpufreq_gov_powersave_exit(void)
{
cpufreq_unregister_governor(&cpufreq_gov_powersave);
}
MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION("CPUfreq policy governor 'powersave'");
MODULE_LICENSE("GPL");
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE
struct cpufreq_governor *cpufreq_default_governor(void)
{
return &cpufreq_gov_powersave;
}
fs_initcall(cpufreq_gov_powersave_init);
#else
module_init(cpufreq_gov_powersave_init);
#endif
module_exit(cpufreq_gov_powersave_exit);