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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
commit863981e96738983919de841ec669e157e6bdaeb0 (patch)
treed6d89a12e7eb8017837c057935a2271290907f76 /drivers/cpufreq/mvebu-cpufreq.c
parent8dec7c70575785729a6a9e6719a955e9c545bcab (diff)
Linux-libre 4.7.1-gnupck-4.7.1-gnu
Diffstat (limited to 'drivers/cpufreq/mvebu-cpufreq.c')
-rw-r--r--drivers/cpufreq/mvebu-cpufreq.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/cpufreq/mvebu-cpufreq.c b/drivers/cpufreq/mvebu-cpufreq.c
new file mode 100644
index 000000000..e920889b9
--- /dev/null
+++ b/drivers/cpufreq/mvebu-cpufreq.c
@@ -0,0 +1,107 @@
+/*
+ * 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);