[PATCH] rust: driver: fix broken intra-doc links to example driver types

[Alice Ryhl <aliceryhl@google.com>]

The `auxiliary` and `pci` modules are conditional on
`CONFIG_AUXILIARY_BUS` and `CONFIG_PCI` respectively. When these are
disabled, the intra-doc links to `auxiliary::Driver` and `pci::Driver`
break, causing rustdoc warnings (or errors with `-D warnings`).

error: unresolved link to `kernel::auxiliary::Driver`
  --> rust/kernel/driver.rs:82:28
   |
82 | //! [`auxiliary::Driver`]: kernel::auxiliary::Driver
   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `auxiliary` in module `kernel`

Fix this by making the documentation for these examples conditional on
the corresponding configuration options.

Fixes: 970a7c68788e ("driver: rust: expand documentation for driver infrastructure")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/driver.rs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
index 9beae2e3d57e72d5155419bc16f58896a3fc38d7..649d06468f411ddf80fac5f3be22d9f83fd404df 100644
--- a/rust/kernel/driver.rs
+++ b/rust/kernel/driver.rs
@@ -33,7 +33,14 @@
 //! }
 //! ```
 //!
-//! For specific examples see [`auxiliary::Driver`], [`pci::Driver`] and [`platform::Driver`].
+//! For specific examples see:
+//!
+//! * [`platform::Driver`](kernel::platform::Driver)
+#![cfg_attr(
+    CONFIG_AUXILIARY_BUS,
+    doc = "* [`auxiliary::Driver`](kernel::auxiliary::Driver)"
+)]
+#![cfg_attr(CONFIG_PCI, doc = "* [`pci::Driver`](kernel::pci::Driver)")]
 //!
 //! The `probe()` callback should return a `impl PinInit<Self, Error>`, i.e. the driver's private
 //! data. The bus abstraction should store the pointer in the corresponding bus device. The generic
@@ -79,7 +86,6 @@
 //!
 //! For this purpose the generic infrastructure in [`device_id`] should be used.
 //!
-//! [`auxiliary::Driver`]: kernel::auxiliary::Driver
 //! [`Core`]: device::Core
 //! [`Device`]: device::Device
 //! [`Device<Core>`]: device::Device<device::Core>
@@ -87,8 +93,6 @@
 //! [`DeviceContext`]: device::DeviceContext
 //! [`device_id`]: kernel::device_id
 //! [`module_driver`]: kernel::module_driver
-//! [`pci::Driver`]: kernel::pci::Driver
-//! [`platform::Driver`]: kernel::platform::Driver
 
 use crate::error::{Error, Result};
 use crate::{acpi, device, of, str::CStr, try_pin_init, types::Opaque, ThisModule};

---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251227-driver-types-5a42cb829b71

Best regards,
-- 
Alice Ryhl <aliceryhl@google.com>