[PATCH] bus: fsl-mc: register the object drivers after misc_class exists

[Vincent Jardin via B4 Relay]

From: Vincent Jardin <vjardin at free.fr>

Unbinding and re-binding the root DPRC fails with:

  sysfs: cannot create duplicate filename '/dev/char/10:256'
    misc_register / fsl_mc_uapi_create_device_file /
    dprc_setup / dprc_probe

Cc: stable+noautosel at kernel.org # niche: root DPRC unbind/rebind only
Fixes: 2cf1e703f066 ("bus: fsl-mc: add fsl-mc userspace support")
Signed-off-by: Vincent Jardin <vjardin at free.fr>
---
Issue found when unbinding/rebinding the root DPRC on an LX2160A.

The failure is silent at bind time and only shows up as a
duplicate /dev/char entry on the second bind.
---
 drivers/bus/fsl-mc/fsl-mc-bus.c | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 66a4fa73c5b86..7f283844e4500 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -1264,35 +1264,43 @@ static int __init fsl_mc_bus_driver_init(void)
 	error = bus_register(&fsl_mc_bus_type);
 	if (error < 0) {
 		pr_err("bus type registration failed: %d\n", error);
-		goto error_cleanup_cache;
+		return error;
 	}
 
-	error = platform_driver_register(&fsl_mc_bus_driver);
-	if (error < 0) {
-		pr_err("platform_driver_register() failed: %d\n", error);
+	error = bus_register_notifier(&platform_bus_type, &fsl_mc_nb);
+	if (error < 0)
 		goto error_cleanup_bus;
-	}
+
+	return 0;
+
+error_cleanup_bus:
+	bus_unregister(&fsl_mc_bus_type);
+	return error;
+}
+postcore_initcall(fsl_mc_bus_driver_init);
+
+static int __init fsl_mc_bus_drivers_init(void)
+{
+	int error;
 
 	error = dprc_driver_init();
 	if (error < 0)
-		goto error_cleanup_driver;
+		return error;
 
 	error = fsl_mc_allocator_driver_init();
 	if (error < 0)
 		goto error_cleanup_dprc_driver;
 
-	return bus_register_notifier(&platform_bus_type, &fsl_mc_nb);
+	error = platform_driver_register(&fsl_mc_bus_driver);
+	if (error < 0) {
+		pr_err("platform_driver_register() failed: %d\n", error);
+		goto error_cleanup_dprc_driver;
+	}
+
+	return 0;
 
 error_cleanup_dprc_driver:
 	dprc_driver_exit();
-
-error_cleanup_driver:
-	platform_driver_unregister(&fsl_mc_bus_driver);
-
-error_cleanup_bus:
-	bus_unregister(&fsl_mc_bus_type);
-
-error_cleanup_cache:
 	return error;
 }
-postcore_initcall(fsl_mc_bus_driver_init);
+subsys_initcall_sync(fsl_mc_bus_drivers_init);

---
base-commit: 786262be6048deab760f68c8acc2c85607165894
change-id: 20260922-for-upstream-fsl-mc-initcall-order-e3316390712b

Best regards,
-- 
Vincent Jardin <vjardin at free.fr>