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/*
* CPUFreq support for Armada 370/XP platforms.
*
* Copyright (C) 2012-2016 Marvell
*
* Yehuda Yitschak <yehuday@marvell.com>
* Gregory Clement <gregory.clement@free-electrons.com>
* Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#define pr_fmt(fmt) "mvebu-pmsu: " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/resource.h>
static int __init armada_xp_pmsu_cpufreq_init(void)
{
struct device_node *np;
struct resource res;
int ret, cpu;
if (!of_machine_is_compatible("marvell,armadaxp"))
return 0;
/*
* In order to have proper cpufreq handling, we need to ensure
* that the Device Tree description of the CPU clock includes
* the definition of the PMU DFS registers. If not, we do not
* register the clock notifier and the cpufreq driver. This
* piece of code is only for compatibility with old Device
* Trees.
*/
np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock");
if (!np)
return 0;
ret = of_address_to_resource(np, 1, &res);
if (ret) {
pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n");
of_node_put(np);
return 0;
}
of_node_put(np);
/*
* For each CPU, this loop registers the operating points
* supported (which are the nominal CPU frequency and half of
* it), and registers the clock notifier that will take care
* of doing the PMSU part of a frequency transition.
*/
for_each_possible_cpu(cpu) {
struct device *cpu_dev;
struct clk *clk;
int ret;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("Cannot get CPU %d\n", cpu);
continue;
}
clk = clk_get(cpu_dev, 0);
if (IS_ERR(clk)) {
pr_err("Cannot get clock for CPU %d\n", cpu);
return PTR_ERR(clk);
}
/*
* In case of a failure of dev_pm_opp_add(), we don't
* bother with cleaning up the registered OPP (there's
* no function to do so), and simply cancel the
* registration of the cpufreq device.
*/
ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0);
if (ret) {
clk_put(clk);
return ret;
}
ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0);
if (ret) {
clk_put(clk);
return ret;
}
ret = dev_pm_opp_set_sharing_cpus(cpu_dev,
cpumask_of(cpu_dev->id));
if (ret)
dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
__func__, ret);
}
platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
return 0;
}
device_initcall(armada_xp_pmsu_cpufreq_init);
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