Am 2019-10-31 18:35, schrieb Florian Fainelli:
On 10/31/19 10:22 AM, Michael Walle wrote:
Am 2019-10-31 00:59, schrieb Michael Walle:
+
+ if (of_property_read_bool(node, "atheros,keep-pll-enabled"))
+ priv->flags |= AT803X_KEEP_PLL_ENABLED;
This should probably be a PHY tunable rather than a Device Tree
property
as this delves more into the policy than the pure hardware
description.
To be frank. I'll first need to look into PHY tunables before
answering ;)
But keep in mind that this clock output might be used anywhere on the
board. It must not have something to do with networking. The PHY has
a
crystal and it can generate these couple of frequencies regardless of
its network operation.
Although it could be used to provide any clock on the board, I don't
know
if that is possible at the moment, because the PHY is configured in
config_init() which is only called when someone brings the interface
up,
correct?
Anyway, I don't know if that is worth the hassle because in almost all
cases the use case is to provide a fixed clock to the MAC for an RGMII
interface. I don't know if that really fits a PHY tunable, because in
the worst case the link won't work at all if the SoC expects an
always-on clock.
Well, that was my question really, is the clock output being controlled
the actual RXC that will feed back to the MAC or is this is another
clock output pin (sorry if you indicated that before and I missed it)?
No it is not the RX clock. The PHY has three clock pins, RX clock, TX
clock and a general purpose CLK_25M pin.
If this is the PHY's RXC, then does the configuration (DSP, PLL, XTAL)
matter at all on the generated output frequency, or is this just a
choice for the board designer, and whether the PHY is configured for
MII/RGMII, it outputs the appropriate clock at 25/125Mhz?
The RXC changes the frequency according to the speed.
--
-michael
