Re: [PATCH net-next v2 5/5] net: dsa: bcm_sf2: Register our slave MDIO bus

Andrew Lunn [off-list ref] writes:

On Tue, Jun 07, 2016 at 12:48:37PM -0400, Vivien Didelot wrote:

quoted

Hi Florian, Andrew,

Vivien Didelot [off-list ref] writes:

quoted

Hum reviewing that again, I see that if one of the 2 subsequent calls to
request_irq fails, you end up with an unregistered MDIO bus.

We have the same issue in the mv88e6xxx legacy probe code if dsa.c fails
to allocate the dsa_switch structure. I'm moving the MDIO register code
to the setup function like you are doing here (good idea!) to fix that.

In fact it doesn't fix the issue because dsa_switch_driver doesn't
provide any remove/teardown function, in which mv88e6xxx and sf2 could
unregister their MDIO bus on switch removal.

Would it be worth it to add such optional function to DSA drivers?

It is not needed with DSA2 binding. The driver is always in control,
and it performs the unregister from the core. So it knows when to
unregister the mdio bus, either because probe has failed for some
reason, or it is being unloaded. That is also why i register the mdio
bus in probe, and unregister it in remove. Normal practice for a
driver.

Yes I know, I was still talking about the legacy code.

With the legacy interface it is tricky. When would you call such a
remove/tairdown function when using the old binding?

That'd go in dsa_switch_destroy I guess, but it just covers the case
where the whole DSA code is unloaded...

        Vivien