CONFIG_PTP_1588_CLOCK_OPTIONAL (not configurable)

configname: CONFIG_PTP_1588_CLOCK_OPTIONAL

Linux Kernel Configuration
└─>Device Drivers
└─>PTP clock support
└─>PTP_1588_CLOCK_OPTIONAL
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Drivers that can optionally use the PTP_1588_CLOCK framework
should depend on this symbol to prevent them from being built
into vmlinux while the PTP support itself is in a loadable
module.
If PTP support is disabled, this dependency will still be
met, and drivers refer to dummy helpers.