PM / domains: Add perf_state attribute to genpd debugfs

Now that genpd supports performance states, add this additional
attribute as part of the power domains debugfs entry, to display
the current performance state for the Power domain.

Suggested-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -2713,6 +2713,19 @@ static int genpd_devices_show(struct seq_file *s, void *data)
 	return ret;
 }
 
+static int genpd_perf_state_show(struct seq_file *s, void *data)
+{
+	struct generic_pm_domain *genpd = s->private;
+
+	if (genpd_lock_interruptible(genpd))
+		return -ERESTARTSYS;
+
+	seq_printf(s, "%u\n", genpd->performance_state);
+
+	genpd_unlock(genpd);
+	return 0;
+}
+
 #define define_genpd_open_function(name) \
 static int genpd_##name##_open(struct inode *inode, struct file *file) \
 { \
@@ -2726,6 +2739,7 @@ define_genpd_open_function(idle_states);
 define_genpd_open_function(active_time);
 define_genpd_open_function(total_idle_time);
 define_genpd_open_function(devices);
+define_genpd_open_function(perf_state);
 
 #define define_genpd_debugfs_fops(name) \
 static const struct file_operations genpd_##name##_fops = { \
@@ -2742,6 +2756,7 @@ define_genpd_debugfs_fops(idle_states);
 define_genpd_debugfs_fops(active_time);
 define_genpd_debugfs_fops(total_idle_time);
 define_genpd_debugfs_fops(devices);
+define_genpd_debugfs_fops(perf_state);
 
 static int __init genpd_debug_init(void)
 {
@@ -2775,6 +2790,9 @@ static int __init genpd_debug_init(void)
 				d, genpd, &genpd_total_idle_time_fops);
 		debugfs_create_file("devices", 0444,
 				d, genpd, &genpd_devices_fops);
+		if (genpd->set_performance_state)
+			debugfs_create_file("perf_state", 0444,
+					    d, genpd, &genpd_perf_state_fops);
 	}
 
 	return 0;