Return value of mii_bus->write()

I am preparing a patch to eliminate kernel-doc warnings in mdio_device.c and mdio_bus.c

I have ran into an ambiguity: what is mii_bus->write() supposed to return on success? Documentation/networking/phy.txt does not give any information about it, neither does the kdoc in include/linux/phy.h.

It is clear that 0 is treated as success, and a negative indicates failure. The reference implementation also follows this convention. But the code in mdio_bus.c, for example: __mdiobus_modify_changed(), seems to also expect positive return values from write().

Is there any other implementation that allows positive return values for success? Should it be mentioned in kernel-doc?

Thanks,
Csaba

Quoted 7 lines · Buday Csaba

I am preparing a patch to eliminate kernel-doc warnings in mdio_device.c and mdio_bus.c

I have ran into an ambiguity: what is mii_bus->write() supposed to return on success? Documentation/networking/phy.txt does not give any information about it, neither does the kdoc in include/linux/phy.h.

Quoted 5 lines

It is clear that 0 is treated as success, and a negative indicates failure. The reference implementation also follows this convention. But the code in mdio_bus.c, for example: __mdiobus_modify_changed(), seems to also expect positive return values from write().

I think you misread the code. __mdiobus_modify_changed() returns a positive value in case new and old value differ, but __mdiobus_write() never returns a positive value.