Re: [PATCH v3] ptp: add ToD device driver for Intel FPGA cards

On Tue, Mar 28, 2023, at 16:42, Richard Cochran wrote:

On Tue, Mar 28, 2023 at 10:24:55AM -0400, Tianfei Zhang wrote:

quoted

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...

quoted

+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.

I think this one is one of the (few) cases where the 'depends on
PTP_1588_CLOCK' is correct and 'depends on PTP_1588_CLOCK_OPTIONAL'
would be wrong:

Using PTP_1588_CLOCK_OPTIONAL as a dependency for PTP_DFL_TOD would
allow enabling the driver even when PTP_1588_CLOCK is completely
disabled, which would cleanly build but not do anything useful
because the driver only handles PTP and not also networking.

     Arnd