Claude review: drm: verisilicon: make vs_format conversion function return int

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Purpose:** Convert `drm_format_to_vs_format()` from void to int return type to enable error reporting.

**Code Analysis:**

```c
-void drm_format_to_vs_format(u32 drm_format, struct vs_format *vs_format)
+int drm_format_to_vs_format(u32 drm_format, struct vs_format *vs_format)
```

This is a straightforward API change. The function signature update is correct.

```c
 	default:
-		pr_warn("Unexpected drm format!\n");
+		return -EINVAL;
 	}
```

**Issue 1 - Error handling improvement:**
Good: Replacing a warning with proper error propagation is correct. However, it would be better to log which format was unexpected for debugging:
```c
default:
	pr_err("Unsupported drm format: 0x%08x\n", drm_format);
	return -EINVAL;
```

```c
 	/* N/A for non-YUV formats */
 	vs_format->uv_swizzle = false;
+
+	return 0;
 }
```

**Issue 2 - Success path:**
The success return is only at the very end. This means if the first switch statement matches a format, but execution continues through the second switch, we always return 0. This appears correct since the default case in the first switch would have returned -EINVAL already. However, this creates implicit coupling between the two switch statements that should be documented.

**Issue 3 - Header includes:**
```c
+#include <drm/drm_atomic_state_helper.h>
```
This include appears unrelated to this patch's functionality (making the function return int). It's likely needed for patch 2 or 3 but was mistakenly added here. This breaks the logical separation of changes and could cause bisection issues.

**Verdict:** The core change is correct, but has header inclusion and error message issues.

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Generated by Claude Code Patch Reviewer