/* * 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, NULL); if (IS_ERR(clk)) { pr_err("Cannot get clock for CPU %d\n", cpu); return PTR_ERR(clk); } 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) { dev_pm_opp_remove(cpu_dev, clk_get_rate(clk)); clk_put(clk); dev_err(cpu_dev, "Failed to register OPPs\n"); 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); clk_put(clk); } platform_device_register_simple("cpufreq-dt", -1, NULL, 0); return 0; } device_initcall(armada_xp_pmsu_cpufreq_init);