Device drivers should not invoke platform_driver_register()/unregister()
in their probe and remove paths. They should further not rely on
platform_driver_unregister() as their only means of "deleting" their
child devices.

Introduce a helper to unregister the child device and move the
platform_driver_register()/unregister() to module_init()/exit().

Fixes: 917809e2280b ("slimbus: ngd: Add qcom SLIMBus NGD driver")
Cc: stable@vger.kernel.org
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>
---
 drivers/slimbus/qcom-ngd-ctrl.c | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index 1ed6be6e85d2cfc0a2b65a5ae24f666de922c89d..b603b9337905438b6c9f5dbe800e560c864d946d 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -1560,6 +1560,13 @@ static int of_qcom_slim_ngd_register(struct device *parent,
 	return -ENODEV;
 }
 
+static void qcom_slim_ngd_unregister(struct qcom_slim_ngd_ctrl *ctrl)
+{
+	struct qcom_slim_ngd *ngd = ctrl->ngd;
+
+	platform_device_del(ngd->pdev);
+}
+
 static int qcom_slim_ngd_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1662,7 +1669,6 @@ static int qcom_slim_ngd_ctrl_probe(struct platform_device *pdev)
 		goto err_pdr_lookup;
 	}
 
-	platform_driver_register(&qcom_slim_ngd_driver);
 	return of_qcom_slim_ngd_register(dev, ctrl);
 
 err_pdr_alloc:
@@ -1676,7 +1682,9 @@ static int qcom_slim_ngd_ctrl_probe(struct platform_device *pdev)
 
 static void qcom_slim_ngd_ctrl_remove(struct platform_device *pdev)
 {
-	platform_driver_unregister(&qcom_slim_ngd_driver);
+	struct qcom_slim_ngd_ctrl *ctrl = platform_get_drvdata(pdev);
+
+	qcom_slim_ngd_unregister(ctrl);
 }
 
 static void qcom_slim_ngd_remove(struct platform_device *pdev)
@@ -1752,6 +1760,28 @@ static struct platform_driver qcom_slim_ngd_driver = {
 	},
 };
 
-module_platform_driver(qcom_slim_ngd_ctrl_driver);
+static int qcom_slim_ngd_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&qcom_slim_ngd_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&qcom_slim_ngd_ctrl_driver);
+	if (ret)
+		platform_driver_unregister(&qcom_slim_ngd_driver);
+
+	return ret;
+}
+
+static void qcom_slim_ngd_exit(void)
+{
+	platform_driver_unregister(&qcom_slim_ngd_ctrl_driver);
+	platform_driver_unregister(&qcom_slim_ngd_driver);
+}
+
+module_init(qcom_slim_ngd_init);
+module_exit(qcom_slim_ngd_exit);
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Qualcomm SLIMBus NGD controller");

-- 
2.51.0