cpufreq: arm_big_little_dt: Register driver only if DT has valid data

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / cpufreq / arm_big_little_dt.c

diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c
index 173ed05..27e2f45 100644 (file)
--- a/drivers/cpufreq/arm_big_little_dt.c
+++ b/drivers/cpufreq/arm_big_little_dt.c
@@ -19,6 +19,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/device.h>
 #include <linux/export.h>
@@ -29,60 +30,63 @@
 #include <linux/types.h>
 #include "arm_big_little.h"
 
-static int dt_init_opp_table(struct device *cpu_dev)
+/* get cpu node with valid operating-points */
+static struct device_node *get_cpu_node_with_valid_op(int cpu)
 {
-       struct device_node *np, *parent;
-       int count = 0, ret;
+       struct device_node *np = NULL, *parent;
+       int count = 0;
 
        parent = of_find_node_by_path("/cpus");
        if (!parent) {
                pr_err("failed to find OF /cpus\n");
-               return -ENOENT;
+               return NULL;
        }
 
        for_each_child_of_node(parent, np) {
-               if (count++ != cpu_dev->id)
+               if (count++ != cpu)
                        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);
+                       np = NULL;
                }
-               of_node_put(np);
-               of_node_put(parent);
 
-               return ret;
+               break;
        }
 
-       return -ENODEV;
+       of_node_put(parent);
+       return np;
+}
+
+static int dt_init_opp_table(struct device *cpu_dev)
+{
+       struct device_node *np;
+       int ret;
+
+       np = get_cpu_node_with_valid_op(cpu_dev->id);
+       if (!np)
+               return -ENODATA;
+
+       cpu_dev->of_node = np;
+       ret = of_init_opp_table(cpu_dev);
+       of_node_put(np);
+
+       return ret;
 }
 
 static int dt_get_transition_latency(struct device *cpu_dev)
 {
-       struct device_node *np, *parent;
+       struct device_node *np;
        u32 transition_latency = CPUFREQ_ETERNAL;
-       int count = 0;
 
-       parent = of_find_node_by_path("/cpus");
-       if (!parent) {
-               pr_info("Failed to find OF /cpus. Use CPUFREQ_ETERNAL transition latency\n");
+       np = get_cpu_node_with_valid_op(cpu_dev->id);
+       if (!np)
                return CPUFREQ_ETERNAL;
-       }
-
-       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 transition_latency;
-       }
+       of_property_read_u32(np, "clock-latency", &transition_latency);
+       of_node_put(np);
 
-       pr_info("clock-latency isn't found, use CPUFREQ_ETERNAL transition latency\n");
-       return CPUFREQ_ETERNAL;
+       pr_debug("%s: clock-latency: %d\n", __func__, transition_latency);
+       return transition_latency;
 }
 
 static struct cpufreq_arm_bL_ops dt_bL_ops = {
@@ -93,6 +97,13 @@ static struct cpufreq_arm_bL_ops dt_bL_ops = {
 
 static int generic_bL_init(void)
 {
+       struct device_node *np;
+
+       np = get_cpu_node_with_valid_op(0);
+       if (!np)
+               return -ENODEV;
+
+       of_node_put(np);
        return bL_cpufreq_register(&dt_bL_ops);
 }
 module_init(generic_bL_init);