linux-stable/drivers/cpufreq/vexpress-spc-cpufreq.c

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/*
* Versatile Express SPC CPUFreq Interface driver
*
* It provides necessary ops to arm_big_little cpufreq driver.
*
* Copyright (C) 2013 ARM Ltd.
* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
*
* 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.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/types.h>
#include "arm_big_little.h"
static int ve_spc_init_opp_table(const struct cpumask *cpumask)
{
struct device *cpu_dev = get_cpu_device(cpumask_first(cpumask));
/*
* platform specific SPC code must initialise the opp table
* so just check if the OPP count is non-zero
*/
return dev_pm_opp_get_opp_count(cpu_dev) <= 0;
}
static int ve_spc_get_transition_latency(struct device *cpu_dev)
{
return 1000000; /* 1 ms */
}
static const struct cpufreq_arm_bL_ops ve_spc_cpufreq_ops = {
.name = "vexpress-spc",
.get_transition_latency = ve_spc_get_transition_latency,
.init_opp_table = ve_spc_init_opp_table,
};
static int ve_spc_cpufreq_probe(struct platform_device *pdev)
{
return bL_cpufreq_register(&ve_spc_cpufreq_ops);
}
static int ve_spc_cpufreq_remove(struct platform_device *pdev)
{
bL_cpufreq_unregister(&ve_spc_cpufreq_ops);
return 0;
}
static struct platform_driver ve_spc_cpufreq_platdrv = {
.driver = {
.name = "vexpress-spc-cpufreq",
},
.probe = ve_spc_cpufreq_probe,
.remove = ve_spc_cpufreq_remove,
};
module_platform_driver(ve_spc_cpufreq_platdrv);
MODULE_LICENSE("GPL");