[CPUFREQ] Export scaling cur frequencies

Many users want to know the current cpu freqeuncy, even if not using
the userspace frequency. On ->target cpufreq drivers (if they do their
calls to cpufreq_notify_transition correctly) this just means reading
out cpufreq_policy->cur.

drivers/cpufreq/cpufreq.c

@@ -161,6 +161,7 @@ show_one(cpuinfo_min_freq, cpuinfo.min_freq);
 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
 show_one(scaling_min_freq, min);
 show_one(scaling_max_freq, max);
+show_one(scaling_cur_freq, cur);
 
 /**
  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
@@ -279,6 +280,7 @@ define_one_ro(cpuinfo_min_freq);
 define_one_ro(cpuinfo_max_freq);
 define_one_ro(scaling_available_governors);
 define_one_ro(scaling_driver);
+define_one_ro(scaling_cur_freq);
 define_one_rw(scaling_min_freq);
 define_one_rw(scaling_max_freq);
 define_one_rw(scaling_governor);
@@ -394,6 +396,8 @@ static int cpufreq_add_dev (struct sys_device * sys_dev)
 		sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
 		drv_attr++;
 	}
+	if (cpufreq_driver->target)
+		sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
 
 	spin_lock_irqsave(&cpufreq_driver_lock, flags);
 	cpufreq_cpu_data[cpu] = policy;