default or selected kernelversion does not have config value CONFIG_PORTWELL_EC.
Result is shown for kernelversion 6.16-rc7

Portwell Embedded Controller driver

modulename: portwell-ec.ko

configname: CONFIG_PORTWELL_EC

Linux Kernel Configuration
└─>Device Drivers
└─>X86 Platform Specific Device Drivers
└─>Watchdog Timer Support
└─>GPIO Support
└─>Portwell Embedded Controller driver
In linux kernel since version 6.1.145 (release Date: 2025-07-14)  
This driver provides support for the GPIO pins and watchdog timer
embedded in Portwell's EC.

Theoretically, this driver should work on multiple Portwell platforms,
but it has only been tested on the Portwell NANO-6064 board.
If you encounter any issues on other boards, please report them.

To compile this driver as a module, choose M here: the module
will be called portwell-ec.

source code: