cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

When we don't have any file in cpu/cpufreq directory we shouldn't
create it. Specially with the introduction of per-policy governor
instance patchset, even governors are moved to
cpu/cpu*/cpufreq/governor-name directory and so this directory is
just not required.

Lets have it only when required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 44 insertions, 4 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index c6ab21880c07..ce9273a7b4e3 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
         NULL
 };
 
-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)
 
@@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
         .release        = cpufreq_sysfs_release,
 };
 
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int cpufreq_get_global_kobject(void)
+{
+        if (!cpufreq_global_kobject_usage++)
+                return kobject_add(cpufreq_global_kobject,
+                                &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+        return 0;
+}
+EXPORT_SYMBOL(cpufreq_get_global_kobject);
+
+void cpufreq_put_global_kobject(void)
+{
+        if (!--cpufreq_global_kobject_usage)
+                kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(cpufreq_put_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+        int ret = cpufreq_get_global_kobject();
+
+        if (!ret) {
+                ret = sysfs_create_file(cpufreq_global_kobject, attr);
+                if (ret)
+                        cpufreq_put_global_kobject();
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+        sysfs_remove_file(cpufreq_global_kobject, attr);
+        cpufreq_put_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
                                    struct cpufreq_policy *policy)
@@ -2020,7 +2060,7 @@ static int __init cpufreq_core_init(void)
                 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
         }
 
-        cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
+        cpufreq_global_kobject = kobject_create();
         BUG_ON(!cpufreq_global_kobject);
         register_syscore_ops(&cpufreq_syscore_ops);