0.43 doesn't build with clang-13

[riesebie]

Is it possible to build tp-smapi with clang? I am running a clang built kernel 5.15.3. tp-smapi build fails with:

DKMS make.log for tp_smapi-0.43 for kernel 5.15.3-galadriel-lxtec-amd64 (x86_64)
2021-11-20T16:46:57 CET
make: Entering directory '/usr/src/linux-5.15.3'
   CC [M]  /var/lib/dkms/tp_smapi/0.43/build/thinkpad_ec.o                                                                                                                                                                                   
   LTO [M] /var/lib/dkms/tp_smapi/0.43/build/thinkpad_ec.lto.o                                                                                                                                                                               
   CC [M]  /var/lib/dkms/tp_smapi/0.43/build/tp_smapi.o
/var/lib/dkms/tp_smapi/0.43/build/tp_smapi.c:202:14: error: invalid use of a cast in a inline asm context requiring an lvalue: remove the cast or build with -fheinous-gnu-extensions                                                       
                           "m"((u16)smapi_port)                                                                                                                                                                                               
                               ~~~~~^~~~~~~~~~                                                                                                                                                                                                
  1 error generated.                                                                                                                                                                                                                          
  make[1]: *** [scripts/Makefile.build:277: /var/lib/dkms/tp_smapi/0.43/build/tp_smapi.o] Error 1                                                                                                                                             
  make: *** [Makefile:1871: /var/lib/dkms/tp_smapi/0.43/build] Error 2                                                                                                                                                                        
  make: Leaving directory '/usr/src/linux-5.15.3'

Same is with 5.14.20

[evgeni]

Given it doesn't build for you, I guess the answer is no? ;)

Never tried to use LLVM to compile it, and given the age of the code, I doubt it will be trivial to fix.

[evgeni]

On the other hand, that cast really seems unnecessary here, smapi_port is an unsigned short which is the same as u16?!

[riesebie]

Well, I would test a possible fix on a clang and a gcc compiled kernel. But I don't have skils to adapt a fix myself.

[evgeni]

I posted an untested (well, it compiles 🤷‍♀️) patch in #55 - mind testing it?