Am 2019-10-31 17:45, schrieb Florian Fainelli:
On 10/30/19 5:14 PM, Michael Walle wrote:
So we can later add atheros,rgmii-io-2v5. That might need a regulator
as well. Maybe add that 2.5V is currently not supported.
There is no special setting for the 2.5V mode. This is how it works:
there is one voltage pad for the RGMII interface. Either you connect
this pad to a 2.5V voltage or you leave it open (well you would
connect some decoupling Cs). If you leave it open the internal LDO,
which seems to be enabled in any case takes over, supplying 1.5V. then
there is a bit in the debug register which can switch the internal LDO
to 1.8V. So if you'll use 2.5V the bit is irrelevant.
Like I said maybe a "rgmii-io-microvolts" is a better property and
only in the 1800000 setting would turn on this bit. but then both
other setting would be a noop.
That would align with the regulator subsystem units, but maybe you
should have the PHY driver be a regulator provider for itself so you
can
chose wether you want to operate at 1.5V or 1.8V, or you have an
external regulator providing I/O supplies. That would make the whole
thing consistent from the driver's perspective and would not
necessarily
be too far fetched from a HW description perspective?
Sounds good. But again, I'm not too familiar with that. Could you give
an
example how the device tree would look like then? Maybe that way I can
work
myself through that regulator stuff.
--
michael
