[PATCH v2] drm/etnaviv: Fix driver unregistering

[Fabio Estevam <festevam@gmail.com>]

From: Fabio Estevam <fabio.estevam@nxp.com>

Russell King reported:

"When removing and reloading the etnaviv module, the following splat
occurs:

sysfs: cannot create duplicate filename '/devices/platform/etnaviv'
CPU: 0 PID: 1471 Comm: modprobe Not tainted 4.17.0+ #1608
Hardware name: Marvell Dove (Cubox)
Backtrace:
[<c00157d4>] (dump_backtrace) from [<c0015b8c>] (show_stack+0x18/0x1c)
 r6:ef033e38 r5:ee07b340 r4:edb9d000 r3:00000000
[<c0015b74>] (show_stack) from [<c0620784>] (dump_stack+0x20/0x28)
[<c0620764>] (dump_stack) from [<c01bcd24>] (sysfs_warn_dup+0x5c/0x70)
[<c01bccc8>] (sysfs_warn_dup) from [<c01bce14>] (sysfs_create_dir_ns+0x90/0x98)
..."

Commit 246774d17fc0 ("drm/etnaviv: remove the need for a gpu-subsystem
DT node") introduced DRM registration via
platform_device_register_simple(), but missed to call
platform_device_unregister() inside etnaviv_exit().

Fix the problem by calling platform_device_unregister() inside
etnaviv_exit(). While at it, also rearrange the function calls
in the exit path to make them happen in the opposite order of
registration.

Tested on a imx6-sabresd board.

Cc: <stable@vger.kernel.org>
Fixes: 246774d17fc0 ("drm/etnaviv: remove the need for a gpu-subsystem DT node")
Reported-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
Changes since v1:
- Make the exit path symmetrical to the init path by calling
platform_device_unregister() inside for_each_compatible_node()

 drivers/gpu/drm/etnaviv/etnaviv_drv.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index e5013a9..626ad8b 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -631,6 +631,8 @@ static struct platform_driver etnaviv_platform_driver = {
 	},
 };
 
+static struct platform_device *etnaviv_drm;
+
 static int __init etnaviv_init(void)
 {
 	int ret;
@@ -654,7 +656,8 @@ static int __init etnaviv_init(void)
 		if (!of_device_is_available(np))
 			continue;
 
-		platform_device_register_simple("etnaviv", -1, NULL, 0);
+		etnaviv_drm = platform_device_register_simple("etnaviv", -1,
+							      NULL, 0);
 		of_node_put(np);
 		break;
 	}
@@ -665,8 +668,19 @@ module_init(etnaviv_init);
 
 static void __exit etnaviv_exit(void)
 {
-	platform_driver_unregister(&etnaviv_gpu_driver);
+	struct device_node *np;
+
+	for_each_compatible_node(np, NULL, "vivante,gc") {
+		if (!of_device_is_available(np))
+			continue;
+
+		platform_device_unregister(etnaviv_drm);
+		of_node_put(np);
+		break;
+	}
+
 	platform_driver_unregister(&etnaviv_platform_driver);
+	platform_driver_unregister(&etnaviv_gpu_driver);
 }
 module_exit(etnaviv_exit);
 
-- 
2.7.4