On Sun, Oct 25, 2020 at 10:27:05PM +0800, Icenowy Zheng wrote:
>
>
> 于 2020年10月25日 GMT+08:00 下午10:18:25, Andrew Lunn <andrew@xxxxxxx> 写到:
> >On Sun, Oct 25, 2020 at 04:55:56PM +0800, Icenowy Zheng wrote:
> >> Currently there are many boards that just set "rgmii" as phy-mode in
> >the
> >> device tree, and leave the hardware [TR]XDLY pins to set PHY delay
> >mode.
> >>
> >> In order to keep old device tree working, omit setting delay for just
> >> "RGMII" without any internal delay suffix, otherwise many devices are
> >> broken.
> >
> >Hi Icenowy
> >
> >We have been here before with the Atheros PHY. It did not correctly
> >implement one of the delay modes, until somebody really did need that
> >mode. So the driver was fixed. And we then found a number of device
> >trees were also buggy. It was painful for a while, but all the device
> >trees got fixed.
>
> 1. As the PHY chip has hardware configuration for configuring delays,
> we should at least have a mode that respects what's set on the hardware.
Yes, that is PHY_INTERFACE_MODE_NA. In DT, set the phy-mode to "". Or
for most MAC drivers, don't list a phy-mode at all.
> 2. As I know, at least Fedora ships a device tree with their bootloader, and
> the DT will not be updated with kernel.
I would check that. Debian does the exact opposite, the last time i
looked. It always uses the DT that come with the kernel because it
understands DT can have bugs, like all software.
Andrew
