drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/Documentation/gpu/nova/guidelines.rst b/Documentation/gpu/nova/guidelines.rst
new file mode 100644
index 000000000..13ab13984
--- /dev/null
+++ b/Documentation/gpu/nova/guidelines.rst
@@ -0,0 +1,69 @@
+.. SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+==========
+Guidelines
+==========
+
+This document describes the general project guidelines that apply to nova-core
+and nova-drm.
+
+Language
+========
+
+The Nova project uses the Rust programming language. In this context, all rules
+of the Rust for Linux project as documented in
+:doc:`../../rust/general-information` apply. Additionally, the following rules
+apply.
+
+- Unless technically necessary otherwise (e.g. uAPI), any driver code is written
+  in Rust.
+
+- Unless technically necessary, unsafe Rust code must be avoided. In case of
+  technical necessity, unsafe code should be isolated in a separate component
+  providing a safe API for other driver code to use.
+
+Style
+-----
+
+All rules of the Rust for Linux project as documented in
+:doc:`../../rust/coding-guidelines` apply.
+
+For a submit checklist, please also see the `Rust for Linux Submit checklist
+addendum <https://rust-for-linux.com/contributing#submit-checklist-addendum>`_.
+
+Documentation
+=============
+
+The availability of proper documentation is essential in terms of scalability,
+accessibility for new contributors and maintainability of a project in general,
+but especially for a driver running as complex hardware as Nova is targeting.
+
+Hence, adding documentation of any kind is very much encouraged by the project.
+
+Besides that, there are some minimum requirements.
+
+- Every non-private structure needs at least a brief doc comment explaining the
+  semantical sense of the structure, as well as potential locking and lifetime
+  requirements. It is encouraged to have the same minimum documentation for
+  non-trivial private structures.
+
+- uAPIs must be fully documented with kernel-doc comments; additionally, the
+  semantical behavior must be explained including potential special or corner
+  cases.
+
+- The APIs connecting the 1st level driver (nova-core) with 2nd level drivers
+  must be fully documented. This includes doc comments, potential locking and
+  lifetime requirements, as well as example code if applicable.
+
+- Abbreviations must be explained when introduced; terminology must be uniquely
+  defined.
+
+- Register addresses, layouts, shift values and masks must be defined properly;
+  unless obvious, the semantical sense must be documented. This only applies if
+  the author is able to obtain the corresponding information.
+
+Acceptance Criteria
+===================
+
+- Patches must only be applied if reviewed by at least one other person on the
+  mailing list; this also applies for maintainers.