Building with the attached random configuration file,

drivers/built-in.o: In function `sur40_disconnect':
sur40.c:(.text+0x15c1cc): undefined reference to
`input_unregister_polled_device'
sur40.c:(.text+0x15c1d5): undefined reference to `input_free_polled_device'
drivers/built-in.o: In function `sur40_probe':
sur40.c:(.text+0x15c47a): undefined reference to `input_allocate_polled_device'
sur40.c:(.text+0x15c65b): undefined reference to `input_register_polled_device'
sur40.c:(.text+0x15c68b): undefined reference to `input_free_polled_device'
make: *** [vmlinux] Error 1