CCing Arnd... On Tue, Mar 28, 2023 at 10:24:55AM -0400, Tianfei Zhang wrote: > v3: > - add PTP_1588_CLOCK dependency for PTP_DFL_TOD in Kconfig file. > - don't need handle NULL case for ptp_clock_register() after adding > PTP_1588_CLOCK dependency. Sorry, but this isn't how it is done... > +config PTP_DFL_TOD > + tristate "FPGA DFL ToD Driver" > + depends on FPGA_DFL > + depends on PTP_1588_CLOCK Try these commands: git grep "depends on PTP_1588_CLOCK_OPTIONAL" git grep "depends on PTP_1588_CLOCK_OPTIONAL" | grep -v OPTIONAL Driver must depend on PTP_1588_CLOCK_OPTIONAL and then handle the NULL case correctly. Thanks, Richard