On 19/08/2021 17:17:05+0000, Vladimir Oltean wrote:
> On Thu, Aug 19, 2021 at 08:04:16PM +0300, Vladimir Oltean wrote:
> > The ocelot driver was converted to phylink, and that expects a valid
> > phy_interface_t. Without a phy-mode, of_get_phy_mode returns
> > PHY_INTERFACE_MODE_NA, which is not ideal because phylink rejects that.
> >
> > The ocelot driver was patched to treat PHY_INTERFACE_MODE_NA as
> > PHY_INTERFACE_MODE_INTERNAL to work with the broken DT blobs, but we
> > should fix the device trees and specify the phy-mode too.
> >
> > Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> > ---
>
> Please note that the pre-phylink driver has this check:
>
> switch (ocelot_port->phy_mode) {
> case PHY_INTERFACE_MODE_NA:
> (...)
> case PHY_INTERFACE_MODE_SGMII:
> (...)
> case PHY_INTERFACE_MODE_QSGMII:
> (...)
> default:
> dev_err(ocelot->dev,
> "invalid phy mode for port%d, (Q)SGMII only\n",
> port);
> of_node_put(portnp);
> err = -EINVAL;
> goto out_teardown;
> }
>
> So it does not actually expect PHY_INTERFACE_MODE_INTERNAL and will
> error out.
>
> Are we okay with the new device tree blobs breaking the old kernel?
>From my point of view, newer device trees are not required to work on
older kernel, this would impose an unreasonable limitation and the use
case is very limited.
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
