cpufreq: Introduce cpufreq_notify_post_transition()

This introduces a new routine cpufreq_notify_post_transition() which
can be used to send POSTCHANGE notification for new freq with or
without both {PRE|POST}CHANGE notifications for last freq. This is
useful at multiple places, especially for sending transition failure
notifications.

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

drivers/cpufreq/cpufreq.c

@@ -320,6 +320,20 @@ void cpufreq_notify_transition(struct cpufreq_policy *policy,
 }
 EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
 
+/* Do post notifications when there are chances that transition has failed */
+void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
+		struct cpufreq_freqs *freqs, int transition_failed)
+{
+	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
+	if (!transition_failed)
+		return;
+
+	swap(freqs->old, freqs->new);
+	cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
+	cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
+}
+EXPORT_SYMBOL_GPL(cpufreq_notify_post_transition);
+
 
 /*********************************************************************
  *                          SYSFS INTERFACE                          *

include/linux/cpufreq.h

@@ -306,6 +306,8 @@ int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
 
 void cpufreq_notify_transition(struct cpufreq_policy *policy,
 		struct cpufreq_freqs *freqs, unsigned int state);
+void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
+		struct cpufreq_freqs *freqs, int transition_failed);
 
 #else /* CONFIG_CPU_FREQ */
 static inline int cpufreq_register_notifier(struct notifier_block *nb,