HID: i2c-hid: Use PM subsystem to manage wake irq

The I2C hid driver is currently manually managing the wake
IRQ. This change removes the explicit enable_irq_wake/disable_irq_wake
and instead relies on the PM subsystem. This is done by calling
dev_pm_set_wake_irq.

i2c_device_probe already calls dev_pm_set_wake_irq when using device
tree, and i2c_device_remove also already calls dev_pm_clear_wake_irq.
There could be some device tree systems that have incorrectly declared
`wake` capabilities, so this change will set the wake irq if one is
missing. This matches the previous behavior.

I tested this on an ACPI system that has a HID touchscreen and verified
the IRQ was armed for wake on suspend.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20220929093200.v6.1.Id4b4bdfe06e2caf2d5a3c9dd4a9b1080c38b539c@changeid
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/hid/i2c-hid/i2c-hid-core.c

@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/pm.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/device.h>
 #include <linux/wait.h>
 #include <linux/err.h>
@@ -112,7 +113,6 @@ struct i2c_hid {
 
 	wait_queue_head_t	wait;		/* For waiting the interrupt */
 
-	bool			irq_wake_enabled;
 	struct mutex		reset_lock;
 
 	struct i2chid_ops	*ops;
@@ -1018,6 +1018,15 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 	if (ret < 0)
 		goto err_powered;
 
+	/*
+	 * The wake IRQ should be declared via device tree instead of assuming
+	 * the IRQ can wake the system. This is here for legacy reasons and
+	 * will be removed once the i2c-core supports querying ACPI for wake
+	 * capabilities.
+	 */
+	if (!client->dev.power.wakeirq)
+		dev_pm_set_wake_irq(&client->dev, client->irq);
+
 	hid = hid_allocate_device();
 	if (IS_ERR(hid)) {
 		ret = PTR_ERR(hid);
@@ -1099,7 +1108,6 @@ static int i2c_hid_core_suspend(struct device *dev)
 	struct i2c_hid *ihid = i2c_get_clientdata(client);
 	struct hid_device *hid = ihid->hid;
 	int ret;
-	int wake_status;
 
 	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
 	if (ret < 0)
@@ -1110,16 +1118,8 @@ static int i2c_hid_core_suspend(struct device *dev)
 
 	disable_irq(client->irq);
 
-	if (device_may_wakeup(&client->dev)) {
-		wake_status = enable_irq_wake(client->irq);
-		if (!wake_status)
-			ihid->irq_wake_enabled = true;
-		else
-			hid_warn(hid, "Failed to enable irq wake: %d\n",
-				wake_status);
-	} else {
+	if (!device_may_wakeup(&client->dev))
 		i2c_hid_core_power_down(ihid);
-	}
 
 	return 0;
 }
@@ -1130,18 +1130,9 @@ static int i2c_hid_core_resume(struct device *dev)
 	struct i2c_client *client = to_i2c_client(dev);
 	struct i2c_hid *ihid = i2c_get_clientdata(client);
 	struct hid_device *hid = ihid->hid;
-	int wake_status;
 
-	if (!device_may_wakeup(&client->dev)) {
+	if (!device_may_wakeup(&client->dev))
 		i2c_hid_core_power_up(ihid);
-	} else if (ihid->irq_wake_enabled) {
-		wake_status = disable_irq_wake(client->irq);
-		if (!wake_status)
-			ihid->irq_wake_enabled = false;
-		else
-			hid_warn(hid, "Failed to disable irq wake: %d\n",
-				wake_status);
-	}
 
 	enable_irq(client->irq);