Slimbus devices can be allocated dynamically upon reception of
report-present messages.

Make sure to drop the reference taken when looking up already registered
devices.

Note that this requires taking an extra reference in case the device has
not yet been registered and has to be allocated.

Fixes: 46a2bb5a7f7e ("slimbus: core: Add slim controllers support")
Cc: stable@vger.kernel.org	# 4.16
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/slimbus/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/slimbus/core.c b/drivers/slimbus/core.c
index 9f85c4280171..b4ab9a5d44b3 100644
--- a/drivers/slimbus/core.c
+++ b/drivers/slimbus/core.c
@@ -379,6 +379,8 @@ struct slim_device *slim_get_device(struct slim_controller *ctrl,
 		sbdev = slim_alloc_device(ctrl, e_addr, NULL);
 		if (!sbdev)
 			return ERR_PTR(-ENOMEM);
+
+		get_device(&sbdev->dev);
 	}
 
 	return sbdev;
@@ -505,6 +507,7 @@ int slim_device_report_present(struct slim_controller *ctrl,
 		ret = slim_device_alloc_laddr(sbdev, true);
 	}
 
+	put_device(&sbdev->dev);
 out_put_rpm:
 	pm_runtime_mark_last_busy(ctrl->dev);
 	pm_runtime_put_autosuspend(ctrl->dev);
-- 
2.51.2