HID: add suspend/resume helpers

There is a lot of duplication of code in the HID low level drivers.
Better have everything in one place so we can eventually extend it
in a generic way.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211202095334.14399-4-benjamin.tissoires@redhat.com

drivers/hid/hid-core.c

@@ -2126,6 +2126,35 @@ void hid_hw_close(struct hid_device *hdev)
 }
 EXPORT_SYMBOL_GPL(hid_hw_close);
 
+#ifdef CONFIG_PM
+int hid_driver_suspend(struct hid_device *hdev, pm_message_t state)
+{
+	if (hdev->driver && hdev->driver->suspend)
+		return hdev->driver->suspend(hdev, state);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_driver_suspend);
+
+int hid_driver_reset_resume(struct hid_device *hdev)
+{
+	if (hdev->driver && hdev->driver->reset_resume)
+		return hdev->driver->reset_resume(hdev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_driver_reset_resume);
+
+int hid_driver_resume(struct hid_device *hdev)
+{
+	if (hdev->driver && hdev->driver->resume)
+		return hdev->driver->resume(hdev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_driver_resume);
+#endif /* CONFIG_PM */
+
 struct hid_dynid {
 	struct list_head list;
 	struct hid_device_id id;

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

@@ -1063,11 +1063,9 @@ static int i2c_hid_core_suspend(struct device *dev)
 	int ret;
 	int wake_status;
 
-	if (hid->driver && hid->driver->suspend) {
-		ret = hid->driver->suspend(hid, PMSG_SUSPEND);
-		if (ret < 0)
-			return ret;
-	}
+	ret = hid_driver_suspend(hid, PMSG_SUSPEND);
+	if (ret < 0)
+		return ret;
 
 	/* Save some power */
 	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
@@ -1125,12 +1123,7 @@ static int i2c_hid_core_resume(struct device *dev)
 	if (ret)
 		return ret;
 
-	if (hid->driver && hid->driver->reset_resume) {
-		ret = hid->driver->reset_resume(hid);
-		return ret;
-	}
-
-	return 0;
+	return hid_driver_reset_resume(hid);
 }
 #endif
 

drivers/hid/surface-hid/surface_hid_core.c

@@ -204,50 +204,35 @@ static int surface_hid_suspend(struct device *dev)
 {
 	struct surface_hid_device *d = dev_get_drvdata(dev);
 
-	if (d->hid->driver && d->hid->driver->suspend)
-		return d->hid->driver->suspend(d->hid, PMSG_SUSPEND);
-
-	return 0;
+	return hid_driver_suspend(d->hid, PMSG_SUSPEND);
 }
 
 static int surface_hid_resume(struct device *dev)
 {
 	struct surface_hid_device *d = dev_get_drvdata(dev);
 
-	if (d->hid->driver && d->hid->driver->resume)
-		return d->hid->driver->resume(d->hid);
-
-	return 0;
+	return hid_driver_resume(d->hid);
 }
 
 static int surface_hid_freeze(struct device *dev)
 {
 	struct surface_hid_device *d = dev_get_drvdata(dev);
 
-	if (d->hid->driver && d->hid->driver->suspend)
-		return d->hid->driver->suspend(d->hid, PMSG_FREEZE);
-
-	return 0;
+	return hid_driver_suspend(d->hid, PMSG_FREEZE);
 }
 
 static int surface_hid_poweroff(struct device *dev)
 {
 	struct surface_hid_device *d = dev_get_drvdata(dev);
 
-	if (d->hid->driver && d->hid->driver->suspend)
-		return d->hid->driver->suspend(d->hid, PMSG_HIBERNATE);
-
-	return 0;
+	return hid_driver_suspend(d->hid, PMSG_HIBERNATE);
 }
 
 static int surface_hid_restore(struct device *dev)
 {
 	struct surface_hid_device *d = dev_get_drvdata(dev);
 
-	if (d->hid->driver && d->hid->driver->reset_resume)
-		return d->hid->driver->reset_resume(d->hid);
-
-	return 0;
+	return hid_driver_reset_resume(d->hid);
 }
 
 const struct dev_pm_ops surface_hid_pm_ops = {

drivers/hid/usbhid/hid-core.c

@@ -1563,8 +1563,8 @@ static int hid_resume_common(struct hid_device *hid, bool driver_suspended)
 	int status = 0;
 
 	hid_restart_io(hid);
-	if (driver_suspended && hid->driver && hid->driver->resume)
-		status = hid->driver->resume(hid);
+	if (driver_suspended)
+		status = hid_driver_resume(hid);
 	return status;
 }
 
@@ -1588,11 +1588,9 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
 		{
 			set_bit(HID_SUSPENDED, &usbhid->iofl);
 			spin_unlock_irq(&usbhid->lock);
-			if (hid->driver && hid->driver->suspend) {
-				status = hid->driver->suspend(hid, message);
-				if (status < 0)
-					goto failed;
-			}
+			status = hid_driver_suspend(hid, message);
+			if (status < 0)
+				goto failed;
 			driver_suspended = true;
 		} else {
 			usbhid_mark_busy(usbhid);
@@ -1602,8 +1600,7 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
 
 	} else {
 		/* TODO: resume() might need to handle suspend failure */
-		if (hid->driver && hid->driver->suspend)
-			status = hid->driver->suspend(hid, message);
+		status = hid_driver_suspend(hid, message);
 		driver_suspended = true;
 		spin_lock_irq(&usbhid->lock);
 		set_bit(HID_SUSPENDED, &usbhid->iofl);
@@ -1644,8 +1641,8 @@ static int hid_reset_resume(struct usb_interface *intf)
 	int status;
 
 	status = hid_post_reset(intf);
-	if (status >= 0 && hid->driver && hid->driver->reset_resume) {
-		int ret = hid->driver->reset_resume(hid);
+	if (status >= 0) {
+		int ret = hid_driver_reset_resume(hid);
 		if (ret < 0)
 			status = ret;
 	}

include/linux/hid.h

@@ -923,6 +923,16 @@ s32 hid_snto32(__u32 value, unsigned n);
 __u32 hid_field_extract(const struct hid_device *hid, __u8 *report,
 		     unsigned offset, unsigned n);
 
+#ifdef CONFIG_PM
+int hid_driver_suspend(struct hid_device *hdev, pm_message_t state);
+int hid_driver_reset_resume(struct hid_device *hdev);
+int hid_driver_resume(struct hid_device *hdev);
+#else
+static inline int hid_driver_suspend(struct hid_device *hdev, pm_message_t state) { return 0; }
+static inline int hid_driver_reset_resume(struct hid_device *hdev) { return 0; }
+static inline int hid_driver_resume(struct hid_device *hdev) { return 0; }
+#endif
+
 /**
  * hid_device_io_start - enable HID input during probe, remove
  *