1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c
new file mode 100644
index 00000000000..44be3115375
--- /dev/null
+++ b/drivers/cpufreq/arm_big_little_dt.c
@@ -0,0 +1,107 @@
+/*
+ * Generic big.LITTLE CPUFreq Interface driver
+ *
+ * It provides necessary ops to arm_big_little cpufreq driver and gets
+ * Frequency information from Device Tree. Freq table in DT must be in KHz.
+ *
+ * Copyright (C) 2013 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/opp.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include "arm_big_little.h"
+
+static int dt_init_opp_table(struct device *cpu_dev)
+{
+	struct device_node *np, *parent;
+	int count = 0, ret;
+
+	parent = of_find_node_by_path("/cpus");
+	if (!parent) {
+		pr_err("failed to find OF /cpus\n");
+		return -ENOENT;
+	}
+
+	for_each_child_of_node(parent, np) {
+		if (count++ != cpu_dev->id)
+			continue;
+		if (!of_get_property(np, "operating-points", NULL)) {
+			ret = -ENODATA;
+		} else {
+			cpu_dev->of_node = np;
+			ret = of_init_opp_table(cpu_dev);
+		}
+		of_node_put(np);
+		of_node_put(parent);
+
+		return ret;
+	}
+
+	return -ENODEV;
+}
+
+static int dt_get_transition_latency(struct device *cpu_dev)
+{
+	struct device_node *np, *parent;
+	u32 transition_latency = CPUFREQ_ETERNAL;
+	int count = 0;
+
+	parent = of_find_node_by_path("/cpus");
+	if (!parent) {
+		pr_err("failed to find OF /cpus\n");
+		return -ENOENT;
+	}
+
+	for_each_child_of_node(parent, np) {
+		if (count++ != cpu_dev->id)
+			continue;
+
+		of_property_read_u32(np, "clock-latency", &transition_latency);
+		of_node_put(np);
+		of_node_put(parent);
+
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
+static struct cpufreq_arm_bL_ops dt_bL_ops = {
+	.name	= "dt-bl",
+	.get_transition_latency = dt_get_transition_latency,
+	.init_opp_table = dt_init_opp_table,
+};
+
+static int generic_bL_init(void)
+{
+	return bL_cpufreq_register(&dt_bL_ops);
+}
+module_init(generic_bL_init);
+
+static void generic_bL_exit(void)
+{
+	return bL_cpufreq_unregister(&dt_bL_ops);
+}
+module_exit(generic_bL_exit);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
+MODULE_LICENSE("GPL");