On Mon, 18 May 2020 11:10:43 -0700, Nathan Chancellor wrote:

This causes a build error with CONFIG_WALNUT because kb_cs and kb_data
were removed in commit 917f0af9e5a9 ("powerpc: Remove arch/ppc and
include/asm-ppc").

ld.lld: error: undefined symbol: kb_cs

quoted

referenced by i8042-ppcio.h:28 (drivers/input/serio/i8042-ppcio.h:28)
input/serio/i8042.o:(__i8042_command) in archive drivers/built-in.a
referenced by i8042-ppcio.h:28 (drivers/input/serio/i8042-ppcio.h:28)
input/serio/i8042.o:(__i8042_command) in archive drivers/built-in.a
referenced by i8042-ppcio.h:28 (drivers/input/serio/i8042-ppcio.h:28)
input/serio/i8042.o:(__i8042_command) in archive drivers/built-in.a

[...]

Applied to powerpc/next.

[1/1] input: i8042 - Remove special PowerPC handling
      https://git.kernel.org/powerpc/c/e4f4ffa8a98c24a4ab482669b1e2b4cfce3f52f4

cheers