You can find these drafts on GitHub. They are usually titled ldd4 or linux-device-drivers-4th-early-draft .
You can find early draft chapters, community-updated versions, and Greg KH’s own driver course materials on GitHub. If you combine the 3rd Edition PDF (legally purchased) with the driver-development GitHub repo , you effectively have a 4th edition. Linux Device Drivers 4th Edition Pdf Github
Many consider this the spiritual successor to the LDD series, covering modern 5.x kernels in depth. You can find these drafts on GitHub