PM / sleep: Report interrupt that caused system wakeup

Add a sysfs attribute, /sys/power/pm_wakeup_irq, reporting the IRQ
number of the first wakeup interrupt (that is, the first interrupt
from an IRQ line armed for system wakeup) seen by the kernel during
the most recent system suspend/resume cycle.

This feature will be useful for system wakeup diagnostics of
spurious wakeup interrupts.

Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com>
[ rjw: Fixed up pm_wakeup_irq definition ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 51f15bc15774..3b361ecfaffc 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -25,6 +25,9 @@
  */
 bool events_check_enabled __read_mostly;
 
+/* First wakeup IRQ seen by the kernel in the last cycle. */
+unsigned int pm_wakeup_irq __read_mostly;
+
 /* If set and the system is suspending, terminate the suspend. */
 static bool pm_abort_suspend __read_mostly;
 
@@ -868,6 +871,15 @@ EXPORT_SYMBOL_GPL(pm_system_wakeup);
 void pm_wakeup_clear(void)
 {
         pm_abort_suspend = false;
+        pm_wakeup_irq = 0;
+}
+
+void pm_system_irq_wakeup(unsigned int irq_number)
+{
+        if (pm_wakeup_irq == 0) {
+                pm_wakeup_irq = irq_number;
+                pm_system_wakeup();
+        }
 }
 
 /**