Hi,
When I try to install TLP on my Thinkpad X250 the install fails and is unable to pull the dependency tp_smapi.
Error message “target not found: tp_smapi”
This happens with the official and AUR versions.
Thanks for your help.
Welcome to the forum! 
The tp_smapi dependency is only optional, not required. You would only need it if you have an older ThinkPad with an Intel CPU before Sandy Bridge.
Install the package corresponding with the kernel you’re using; i.e. for 6.1 install linux61-rt-tp_smapi:
❯ pamac search --repos tp_smapi
tpacpi-bat 3.2-1 extra
A Perl script with ACPI calls for recent ThinkPads (such as T420 and W520) whose battery thresholds are not supported by tp_smapi
linux65-tp_smapi 0.43-9 extra
Modules for ThinkPad's SMAPI functionality
linux65-rt-tp_smapi 0.43-1 extra
Modules for ThinkPad's SMAPI functionality
linux64-tp_smapi 0.43-29 extra
Modules for ThinkPad's SMAPI functionality
linux64-rt-tp_smapi 0.43-4 extra
Modules for ThinkPad's SMAPI functionality
linux61-tp_smapi 0.43-62 extra
Modules for ThinkPad's SMAPI functionality
linux61-rt-tp_smapi 0.43-7 extra
Modules for ThinkPad's SMAPI functionality
linux54-tp_smapi 0.43-283 extra
Modules for ThinkPad's SMAPI functionality
linux515-tp_smapi 0.43-157 extra
Modules for ThinkPad's SMAPI functionality
linux510-tp_smapi 0.43-229 extra
Modules for ThinkPad's SMAPI functionality
linux419-tp_smapi 0.43-256 extra
Modules for ThinkPad's SMAPI functionality
EDIT:
That will no longer happen as of the 0.44-1 packages in the Manjaro unstable branch:
❯ pamac install --as-deps tp_smapi
Choose a provider for tp_smapi:
1: linux419-tp_smapi 0.44-1 extra
2: linux510-tp_smapi 0.44-1 extra
3: linux515-tp_smapi 0.44-1 extra
4: linux54-tp_smapi 0.44-1 extra
5: linux61-rt-tp_smapi 0.44-1 extra
6: linux61-tp_smapi 0.44-1 extra
7: linux64-rt-tp_smapi 0.44-1 extra
8: linux64-tp_smapi 0.44-1 extra
9: linux65-rt-tp_smapi 0.44-1 extra
10: linux65-tp_smapi 0.44-1 extra
Enter a number (default=1):