linux/drivers/cpufreq/loongson2_cpufreq.c
Viresh Kumar c4dcc8a162 cpufreq: Make cpufreq_generic_init() return void
It always returns 0 (success) and its return type should really be void.

Over that, many drivers have added error handling code based on its
return value, which is not required at all.

Change its return type to void and update all the callers.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-16 10:20:11 +02:00

198 lines
4.5 KiB
C

/*
* Cpufreq driver for the loongson-2 processors
*
* The 2E revision of loongson processor not support this feature.
*
* Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
* Author: Yanhua, yanh@lemote.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/sched.h> /* set_cpus_allowed() */
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <asm/clock.h>
#include <asm/idle.h>
#include <asm/mach-loongson64/loongson.h>
static uint nowait;
static void (*saved_cpu_wait) (void);
static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
unsigned long val, void *data);
static struct notifier_block loongson2_cpufreq_notifier_block = {
.notifier_call = loongson2_cpu_freq_notifier
};
static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
unsigned long val, void *data)
{
if (val == CPUFREQ_POSTCHANGE)
current_cpu_data.udelay_val = loops_per_jiffy;
return 0;
}
/*
* Here we notify other drivers of the proposed change and the final change.
*/
static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
unsigned int freq;
freq =
((cpu_clock_freq / 1000) *
loongson2_clockmod_table[index].driver_data) / 8;
/* setting the cpu frequency */
clk_set_rate(policy->clk, freq * 1000);
return 0;
}
static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
struct clk *cpuclk;
int i;
unsigned long rate;
int ret;
cpuclk = clk_get(NULL, "cpu_clk");
if (IS_ERR(cpuclk)) {
pr_err("couldn't get CPU clk\n");
return PTR_ERR(cpuclk);
}
rate = cpu_clock_freq / 1000;
if (!rate) {
clk_put(cpuclk);
return -EINVAL;
}
/* clock table init */
for (i = 2;
(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
i++)
loongson2_clockmod_table[i].frequency = (rate * i) / 8;
ret = clk_set_rate(cpuclk, rate * 1000);
if (ret) {
clk_put(cpuclk);
return ret;
}
policy->clk = cpuclk;
cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
return 0;
}
static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
{
clk_put(policy->clk);
return 0;
}
static struct cpufreq_driver loongson2_cpufreq_driver = {
.name = "loongson2",
.init = loongson2_cpufreq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = loongson2_cpufreq_target,
.get = cpufreq_generic_get,
.exit = loongson2_cpufreq_exit,
.attr = cpufreq_generic_attr,
};
static const struct platform_device_id platform_device_ids[] = {
{
.name = "loongson2_cpufreq",
},
{}
};
MODULE_DEVICE_TABLE(platform, platform_device_ids);
static struct platform_driver platform_driver = {
.driver = {
.name = "loongson2_cpufreq",
},
.id_table = platform_device_ids,
};
/*
* This is the simple version of Loongson-2 wait, Maybe we need do this in
* interrupt disabled context.
*/
static DEFINE_SPINLOCK(loongson2_wait_lock);
static void loongson2_cpu_wait(void)
{
unsigned long flags;
u32 cpu_freq;
spin_lock_irqsave(&loongson2_wait_lock, flags);
cpu_freq = LOONGSON_CHIPCFG(0);
LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */
LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */
spin_unlock_irqrestore(&loongson2_wait_lock, flags);
local_irq_enable();
}
static int __init cpufreq_init(void)
{
int ret;
/* Register platform stuff */
ret = platform_driver_register(&platform_driver);
if (ret)
return ret;
pr_info("Loongson-2F CPU frequency driver\n");
cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
if (!ret && !nowait) {
saved_cpu_wait = cpu_wait;
cpu_wait = loongson2_cpu_wait;
}
return ret;
}
static void __exit cpufreq_exit(void)
{
if (!nowait && saved_cpu_wait)
cpu_wait = saved_cpu_wait;
cpufreq_unregister_driver(&loongson2_cpufreq_driver);
cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
platform_driver_unregister(&platform_driver);
}
module_init(cpufreq_init);
module_exit(cpufreq_exit);
module_param(nowait, uint, 0644);
MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
MODULE_LICENSE("GPL");