PM / Wakeirq: Add automated device wake IRQ handling

Turns out we can automate the handling for the device_may_wakeup()
quite a bit by using the kernel wakeup source list as suggested
by Rafael J. Wysocki <rjw@rjwysocki.net>.

And as some hardware has separate dedicated wake-up interrupt
in addition to the IO interrupt, we can automate the handling by
adding a generic threaded interrupt handler that just calls the
device PM runtime to wake up the device.

This allows dropping code from device drivers as we currently
are doing it in multiple ways, and often wrong.

For most drivers, we should be able to drop the following
boilerplate code from runtime_suspend and runtime_resume
functions:

	...
	device_init_wakeup(dev, true);
	...
	if (device_may_wakeup(dev))
		enable_irq_wake(irq);
	...
	if (device_may_wakeup(dev))
		disable_irq_wake(irq);
	...
	device_init_wakeup(dev, false);
	...

We can replace it with just the following init and exit
time code:

	...
	device_init_wakeup(dev, true);
	dev_pm_set_wake_irq(dev, irq);
	...
	dev_pm_clear_wake_irq(dev);
	device_init_wakeup(dev, false);
	...

And for hardware with dedicated wake-up interrupts:

	...
	device_init_wakeup(dev, true);
	dev_pm_set_dedicated_wake_irq(dev, irq);
	...
	dev_pm_clear_wake_irq(dev);
	device_init_wakeup(dev, false);
	...

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 77262009f89d..7332ebc9cab0 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -14,6 +14,7 @@
 #include <linux/suspend.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
+#include <linux/pm_wakeirq.h>
 #include <trace/events/power.h>
 
 #include "power.h"
@@ -239,6 +240,97 @@ int device_wakeup_enable(struct device *dev)
 EXPORT_SYMBOL_GPL(device_wakeup_enable);
 
 /**
+ * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
+ * @dev: Device to handle
+ * @wakeirq: Device specific wakeirq entry
+ *
+ * Attach a device wakeirq to the wakeup source so the device
+ * wake IRQ can be configured automatically for suspend and
+ * resume.
+ */
+int device_wakeup_attach_irq(struct device *dev,
+			     struct wake_irq *wakeirq)
+{
+	struct wakeup_source *ws;
+	int ret = 0;
+
+	spin_lock_irq(&dev->power.lock);
+	ws = dev->power.wakeup;
+	if (!ws) {
+		dev_err(dev, "forgot to call call device_init_wakeup?\n");
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	if (ws->wakeirq) {
+		ret = -EEXIST;
+		goto unlock;
+	}
+
+	ws->wakeirq = wakeirq;
+
+unlock:
+	spin_unlock_irq(&dev->power.lock);
+
+	return ret;
+}
+
+/**
+ * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
+ * @dev: Device to handle
+ *
+ * Removes a device wakeirq from the wakeup source.
+ */
+void device_wakeup_detach_irq(struct device *dev)
+{
+	struct wakeup_source *ws;
+
+	spin_lock_irq(&dev->power.lock);
+	ws = dev->power.wakeup;
+	if (!ws)
+		goto unlock;
+
+	ws->wakeirq = NULL;
+
+unlock:
+	spin_unlock_irq(&dev->power.lock);
+}
+
+/**
+ * device_wakeup_arm_wake_irqs(void)
+ *
+ * Itereates over the list of device wakeirqs to arm them.
+ */
+void device_wakeup_arm_wake_irqs(void)
+{
+	struct wakeup_source *ws;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+		if (ws->wakeirq)
+			dev_pm_arm_wake_irq(ws->wakeirq);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * device_wakeup_disarm_wake_irqs(void)
+ *
+ * Itereates over the list of device wakeirqs to disarm them.
+ */
+void device_wakeup_disarm_wake_irqs(void)
+{
+	struct wakeup_source *ws;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+		if (ws->wakeirq)
+			dev_pm_disarm_wake_irq(ws->wakeirq);
+	}
+	rcu_read_unlock();
+}
+
+/**
  * device_wakeup_detach - Detach a device's wakeup source object from it.
  * @dev: Device to detach the wakeup source object from.
  *