[PATCH v2 net-next] net: ethernet: ti: davinci_mdio: Add workaround for errata i2329
Ravi Gunasekaran
r-gunasekaran at ti.com
Thu Aug 11 21:36:05 PDT 2022
>> There is atleast one device sh_eth, which is not configured for autosuspend
>> but uses the bit bang core in sh_mdiobb_read() and invokes regular runtime
>> PM functions.
>
> And that is the point of moving it into the core. It would of just
> worked for you.
>
> If you don't feel comfortable with making this unconditional, please
> put runtime pm enabled version of mdiobb_read/mdiobb_write() in the
> core and swap sh_eth and any other drivers to using them.
>
sh_eth is not configured for autosuspend and uses only pm_runtime_put().
davinci_mdio is configured for autosuspend and it must invoke
pm_runtime_mark_last_busy() before calling pm_runtime_put_autosuspend().
So it looks like, there needs to be a runtime PM version of
mdiobb_read/mdiobb_write() for each pm_runtime_put_*(). As of now, it's
only sh_eth which is currently using runtime PM and davinci_mdio would
be the next one. So at least in this case, two variants of
mdiobb_read/mdiobb_write() could be added at the moment. By checking
against the dev->power.use_autosuspend flag, it is possible to support
both via a single version.
That being said, I'm quite inclined towards the existing implementation,
where drivers can have wrappers written around
mdiobb_read/mdiobb_write(). But I might be failing to see the broader
picture. If having multiple runtime PM versions of
mdiobb_read/mdiobb_write() benefits many other future drivers, then I
will go ahead and add the variant(s) in the bitbang core.
Please provide your views on this. Your inputs on the next course of
action would be helpful.
--
Regards,
Ravi
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