default or selected kernelversion does not have config value CONFIG_DRM_OMAP_ENCODER_TPD12S015.
Result is shown for kernelversion 6.9.9

TPD12S015 HDMI ESD protection and level shifter

modulename: encoder-tpd12s015.ko

configname: CONFIG_DRM_OMAP_ENCODER_TPD12S015

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>OMAPDRM External Display Device Drivers
└─>TPD12S015 HDMI ESD protection and level shifter
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Driver for TPD12S015, which offers HDMI ESD protection and level
shifting.

source code: