1/*
  2 * CPUFreq support for Armada 370/XP platforms.
  3 *
  4 * Copyright (C) 2012-2016 Marvell
  5 *
  6 * Yehuda Yitschak <yehuday@marvell.com>
  7 * Gregory Clement <gregory.clement@free-electrons.com>
  8 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  9 *
 10 * This file is licensed under the terms of the GNU General Public
 11 * License version 2.  This program is licensed "as is" without any
 12 * warranty of any kind, whether express or implied.
 13 */
 14
 15#define pr_fmt(fmt) "mvebu-pmsu: " fmt
 16
 17#include <linux/clk.h>
 18#include <linux/cpu.h>
 19#include <linux/init.h>
 20#include <linux/kernel.h>
 21#include <linux/of_address.h>
 22#include <linux/platform_device.h>
 23#include <linux/pm_opp.h>
 24#include <linux/resource.h>
 25
 26static int __init armada_xp_pmsu_cpufreq_init(void)
 27{
 28	struct device_node *np;
 29	struct resource res;
 30	int ret, cpu;
 31
 32	if (!of_machine_is_compatible("marvell,armadaxp"))
 33		return 0;
 34
 35	/*
 36	 * In order to have proper cpufreq handling, we need to ensure
 37	 * that the Device Tree description of the CPU clock includes
 38	 * the definition of the PMU DFS registers. If not, we do not
 39	 * register the clock notifier and the cpufreq driver. This
 40	 * piece of code is only for compatibility with old Device
 41	 * Trees.
 42	 */
 43	np = of_find_compatible_node(NULL, NULL, "marvell,armada-xp-cpu-clock");
 44	if (!np)
 45		return 0;
 46
 47	ret = of_address_to_resource(np, 1, &res);
 48	if (ret) {
 49		pr_warn(FW_WARN "not enabling cpufreq, deprecated armada-xp-cpu-clock binding\n");
 50		of_node_put(np);
 51		return 0;
 52	}
 53
 54	of_node_put(np);
 55
 56	/*
 57	 * For each CPU, this loop registers the operating points
 58	 * supported (which are the nominal CPU frequency and half of
 59	 * it), and registers the clock notifier that will take care
 60	 * of doing the PMSU part of a frequency transition.
 61	 */
 62	for_each_possible_cpu(cpu) {
 63		struct device *cpu_dev;
 64		struct clk *clk;
 65		int ret;
 66
 67		cpu_dev = get_cpu_device(cpu);
 68		if (!cpu_dev) {
 69			pr_err("Cannot get CPU %d\n", cpu);
 70			continue;
 71		}
 72
 73		clk = clk_get(cpu_dev, NULL);
 74		if (IS_ERR(clk)) {
 75			pr_err("Cannot get clock for CPU %d\n", cpu);
 76			return PTR_ERR(clk);
 77		}
 78
 79		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk), 0);
 80		if (ret) {
 81			clk_put(clk);
 82			return ret;
 83		}
 84
 85		ret = dev_pm_opp_add(cpu_dev, clk_get_rate(clk) / 2, 0);
 86		if (ret) {
 87			dev_pm_opp_remove(cpu_dev, clk_get_rate(clk));
 88			clk_put(clk);
 89			dev_err(cpu_dev, "Failed to register OPPs\n");
 90			return ret;
 91		}
 92
 93		ret = dev_pm_opp_set_sharing_cpus(cpu_dev,
 94						  cpumask_of(cpu_dev->id));
 95		if (ret)
 96			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 97				__func__, ret);
 98		clk_put(clk);
 99	}
100
101	platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
102	return 0;
103}
104device_initcall(armada_xp_pmsu_cpufreq_init);