platform/x86/lenovo: Yoga Book 9 keyboard dock detection

Hi Ilpo,

Thank you for the v7 review.  All nine items are addressed in v8.

One item needs a brief explanation: for the mutex lifecycle, I used
__MUTEX_INITIALIZER(yb9.lock) in the struct definition rather than
devm_mutex_init().  The yb9 struct is a module-level global with no
associated device at __init time, and since yb9_kbdock_block_probe()
acquires the lock and can run before yb9_kbdock_event_probe(), the
mutex must be valid before either probe runs.  Static initialization
achieves the same goal (no manual init/destroy lifecycle) without
requiring a device pointer.  If you'd prefer a different approach,
please let me know.

Changes in v8:
  - Add #include <linux/bits.h> (required for GENMASK).
  - Add #include <linux/dev_printk.h> (explicit include for dev_warn/dev_dbg).
  - Use __MUTEX_INITIALIZER(yb9.lock) for static mutex initialization;
    removes mutex_init() call and the need for mutex_destroy().
  - Update wmidev_query_block() call to pass min_size=8; remove manual
    length check now handled by the WMI core.
  - Move u8 *data __free(kfree) declaration to immediately after the
    successful wmidev_query_block() call (cleanup.h convention).
  - Change data type from void * to u8 * to allow pointer arithmetic
    without cast.
  - Remove (int) cast from FIELD_GET() return value.
  - Remove blank line between yb9_kbdock_query_locked() call and error
    check in keyboard_position_show().
  - Use %d format specifier in sysfs_emit(); remove (unsigned int) cast.

Patch 1/2 (lenovo-ymc) is unchanged from v7.

Tested on Lenovo Yoga Book 9 14IAH10 (model 83KJ), kernel 7.0.

Dave Carey (2):
  platform/x86/lenovo: lenovo-ymc: Suppress probe on Yoga Book 9 14IAH10
  platform/x86/lenovo: Add Yoga Book 9 keyboard dock detection driver

 .../testing/sysfs-driver-lenovo-yb9-kbdock    |  19 ++
 MAINTAINERS                                    |   7 +
 drivers/platform/x86/lenovo/Kconfig            |  14 +
 drivers/platform/x86/lenovo/Makefile           |   1 +
 drivers/platform/x86/lenovo/yb9-kbdock.c      | 312 ++++++++++++++++++
 drivers/platform/x86/lenovo/ymc.c              |  19 ++
 6 files changed, 372 insertions(+)

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2.54.0