Although the source code is there for the driver, the configuration file KConfig does not seem to be actualized with the source code in the directory: drivers/input/misc As a result the "yealink" driver for the Yealink USB phone is not built. I did not try to match other entries in KConfig with the files available in the directory, but there may be other configuration options missing. I made the change myself in the config file and now it builds fine. However, I think that Kconfig should be fixed in the main tree. Thanks.
This driver depends on "EXPERIMENTAL": config INPUT_YEALINK tristate "Yealink usb-p1k voip phone" depends on EXPERIMENTAL so if you enable that EXPERIMENTAL kconfig symbol, you should be able to also enable the yealink driver.
Thanks, it works. I had no idea that the driver depends on experimental. It would be nice if it will show grayed out so I know that it exists somehow. I'll close the bug. Sorry for the inconvenience.
xconfig will show it grayed out if you have Option: Show all options enabled/set/checked. menuconfig and/or nconfig will show it if you search for "yealink" using the / (slash) search command. You can see there that it depends on EXPERIMENTAL.