Add missing error check for platform_get_resource() return value to
prevent NULL pointer dereference when memory resource is not available.

Fixes: 718b3bb9c0ab ("drm/rockchip: analogix_dp: Expand device data to support multiple edp display")
Cc: stable@vger.kernel.org
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
---
Changes in v2:
- Add Reviewed-by tag from Dragan Simic
- Add Cc stable tag as suggested
---
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index fdab71d51e2a..3f5be14010c1 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -461,6 +461,8 @@ static int rockchip_dp_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
 
 	i = 0;
 	while (dp_data[i].reg) {
-- 
2.25.1