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Based on the normalized pattern: 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference. Reviewed-by: Allison Randal <allison@lohutok.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
231 lines
5.1 KiB
C
231 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* System Control and Power Interface (SCPI) based CPUFreq Interface driver
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*
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* Copyright (C) 2015 ARM Ltd.
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* Sudeep Holla <sudeep.holla@arm.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/clk.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/pm_opp.h>
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#include <linux/scpi_protocol.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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struct scpi_data {
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struct clk *clk;
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struct device *cpu_dev;
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};
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static struct scpi_ops *scpi_ops;
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static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
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struct scpi_data *priv = policy->driver_data;
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unsigned long rate = clk_get_rate(priv->clk);
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return rate / 1000;
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}
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static int
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scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
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{
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u64 rate = policy->freq_table[index].frequency * 1000;
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struct scpi_data *priv = policy->driver_data;
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int ret;
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ret = clk_set_rate(priv->clk, rate);
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if (ret)
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return ret;
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if (clk_get_rate(priv->clk) != rate)
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return -EIO;
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return 0;
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}
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static int
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scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
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{
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int cpu, domain, tdomain;
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struct device *tcpu_dev;
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domain = scpi_ops->device_domain_id(cpu_dev);
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if (domain < 0)
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return domain;
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for_each_possible_cpu(cpu) {
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if (cpu == cpu_dev->id)
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continue;
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tcpu_dev = get_cpu_device(cpu);
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if (!tcpu_dev)
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continue;
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tdomain = scpi_ops->device_domain_id(tcpu_dev);
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if (tdomain == domain)
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cpumask_set_cpu(cpu, cpumask);
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}
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return 0;
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}
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static int scpi_cpufreq_init(struct cpufreq_policy *policy)
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{
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int ret;
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unsigned int latency;
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struct device *cpu_dev;
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struct scpi_data *priv;
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struct cpufreq_frequency_table *freq_table;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("failed to get cpu%d device\n", policy->cpu);
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return -ENODEV;
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}
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ret = scpi_ops->add_opps_to_device(cpu_dev);
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if (ret) {
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dev_warn(cpu_dev, "failed to add opps to the device\n");
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return ret;
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}
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ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_warn(cpu_dev, "failed to get sharing cpumask\n");
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return ret;
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}
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ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
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__func__, ret);
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return ret;
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}
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ret = dev_pm_opp_get_opp_count(cpu_dev);
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if (ret <= 0) {
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dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
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ret = -EPROBE_DEFER;
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goto out_free_opp;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto out_free_opp;
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}
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ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
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if (ret) {
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dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
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goto out_free_priv;
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}
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priv->cpu_dev = cpu_dev;
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priv->clk = clk_get(cpu_dev, NULL);
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if (IS_ERR(priv->clk)) {
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dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
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__func__, cpu_dev->id);
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ret = PTR_ERR(priv->clk);
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goto out_free_cpufreq_table;
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}
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policy->driver_data = priv;
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policy->freq_table = freq_table;
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/* scpi allows DVFS request for any domain from any CPU */
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policy->dvfs_possible_from_any_cpu = true;
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latency = scpi_ops->get_transition_latency(cpu_dev);
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if (!latency)
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latency = CPUFREQ_ETERNAL;
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policy->cpuinfo.transition_latency = latency;
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policy->fast_switch_possible = false;
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return 0;
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out_free_cpufreq_table:
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dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
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out_free_priv:
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kfree(priv);
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out_free_opp:
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dev_pm_opp_remove_all_dynamic(cpu_dev);
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return ret;
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}
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static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct scpi_data *priv = policy->driver_data;
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clk_put(priv->clk);
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dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
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dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
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kfree(priv);
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return 0;
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}
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static struct cpufreq_driver scpi_cpufreq_driver = {
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.name = "scpi-cpufreq",
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.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
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CPUFREQ_NEED_INITIAL_FREQ_CHECK |
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CPUFREQ_IS_COOLING_DEV,
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.verify = cpufreq_generic_frequency_table_verify,
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.attr = cpufreq_generic_attr,
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.get = scpi_cpufreq_get_rate,
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.init = scpi_cpufreq_init,
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.exit = scpi_cpufreq_exit,
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.target_index = scpi_cpufreq_set_target,
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.register_em = cpufreq_register_em_with_opp,
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};
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static int scpi_cpufreq_probe(struct platform_device *pdev)
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{
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int ret;
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scpi_ops = get_scpi_ops();
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if (!scpi_ops)
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return -EIO;
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ret = cpufreq_register_driver(&scpi_cpufreq_driver);
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if (ret)
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dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
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__func__, ret);
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return ret;
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}
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static int scpi_cpufreq_remove(struct platform_device *pdev)
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{
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cpufreq_unregister_driver(&scpi_cpufreq_driver);
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scpi_ops = NULL;
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return 0;
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}
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static struct platform_driver scpi_cpufreq_platdrv = {
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.driver = {
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.name = "scpi-cpufreq",
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},
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.probe = scpi_cpufreq_probe,
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.remove = scpi_cpufreq_remove,
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};
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module_platform_driver(scpi_cpufreq_platdrv);
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MODULE_ALIAS("platform:scpi-cpufreq");
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
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MODULE_LICENSE("GPL v2");
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