linux/drivers/macintosh/windfarm_cpufreq_clamp.c
Benjamin Herrenschmidt 6cd3209967 powerpc/powermac: New windfarm driver for PowerMac G5 (AGP) and Xserve G5
This replaces the old therm_pm72 using the same windfarm infrastructure
that was used for other PowerMac G5 models. The fan speeds and sensors
should now be visible in the same location in sysfs.

The driver is split into separate core modules for PowerMac7,2 (and 7,3)
and RackMac3,1, with a lot of the shared code now in the separate sensor
and control modules.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-04-30 15:37:25 +10:00

107 lines
2.1 KiB
C

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/cpufreq.h>
#include <asm/prom.h>
#include "windfarm.h"
#define VERSION "0.3"
static int clamped;
static struct wf_control *clamp_control;
static int clamp_notifier_call(struct notifier_block *self,
unsigned long event, void *data)
{
struct cpufreq_policy *p = data;
unsigned long max_freq;
if (event != CPUFREQ_ADJUST)
return 0;
max_freq = clamped ? (p->cpuinfo.min_freq) : (p->cpuinfo.max_freq);
cpufreq_verify_within_limits(p, 0, max_freq);
return 0;
}
static struct notifier_block clamp_notifier = {
.notifier_call = clamp_notifier_call,
};
static int clamp_set(struct wf_control *ct, s32 value)
{
if (value)
printk(KERN_INFO "windfarm: Clamping CPU frequency to "
"minimum !\n");
else
printk(KERN_INFO "windfarm: CPU frequency unclamped !\n");
clamped = value;
cpufreq_update_policy(0);
return 0;
}
static int clamp_get(struct wf_control *ct, s32 *value)
{
*value = clamped;
return 0;
}
static s32 clamp_min(struct wf_control *ct)
{
return 0;
}
static s32 clamp_max(struct wf_control *ct)
{
return 1;
}
static struct wf_control_ops clamp_ops = {
.set_value = clamp_set,
.get_value = clamp_get,
.get_min = clamp_min,
.get_max = clamp_max,
.owner = THIS_MODULE,
};
static int __init wf_cpufreq_clamp_init(void)
{
struct wf_control *clamp;
clamp = kmalloc(sizeof(struct wf_control), GFP_KERNEL);
if (clamp == NULL)
return -ENOMEM;
cpufreq_register_notifier(&clamp_notifier, CPUFREQ_POLICY_NOTIFIER);
clamp->ops = &clamp_ops;
clamp->name = "cpufreq-clamp";
if (wf_register_control(clamp))
goto fail;
clamp_control = clamp;
return 0;
fail:
kfree(clamp);
return -ENODEV;
}
static void __exit wf_cpufreq_clamp_exit(void)
{
if (clamp_control)
wf_unregister_control(clamp_control);
}
module_init(wf_cpufreq_clamp_init);
module_exit(wf_cpufreq_clamp_exit);
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("CPU frequency clamp for PowerMacs thermal control");
MODULE_LICENSE("GPL");