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, 31 insertions, 0 deletions

diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
new file mode 100644
index 000000000..37df7e805
--- /dev/null
+++ b/drivers/rtc/nvmem.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, nvmem interface
+ *
+ * Copyright (C) 2017 Alexandre Belloni
+ */
+
+#include <linux/err.h>
+#include <linux/types.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/rtc.h>
+
+int devm_rtc_nvmem_register(struct rtc_device *rtc,
+		       struct nvmem_config *nvmem_config)
+{
+	struct device *dev = rtc->dev.parent;
+	struct nvmem_device *nvmem;
+
+	if (!nvmem_config)
+		return -ENODEV;
+
+	nvmem_config->dev = dev;
+	nvmem_config->owner = rtc->owner;
+	nvmem_config->add_legacy_fixed_of_cells = true;
+	nvmem = devm_nvmem_register(dev, nvmem_config);
+	if (IS_ERR(nvmem))
+		dev_err(dev, "failed to register nvmem device for RTC\n");
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+EXPORT_SYMBOL_GPL(devm_rtc_nvmem_register);