[PATCH 2/2] net: ethernet: stmicro: stmmac: dwmac-rk: Add rv1126 support

[Anand Moon]

Hi Andrew,

On Mon, 29 Aug 2022 at 18:40, Andrew Lunn <andrew at lunn.ch> wrote:
>
> On Mon, Aug 29, 2022 at 06:50:42AM +0000, Anand Moon wrote:
> > Rockchip RV1126 has GMAC 10/100/1000M ethernet controller
> > via RGMII and RMII interfaces are configured via M0 and M1 pinmux.
> >
> > This patch adds rv1126 support by adding delay lines of M0 and M1
> > simultaneously.
>
> What does 'delay lines' mean with respect to RGMII?
>
> The RGMII signals need a 2ns delay between the clock and the data
> lines. There are three places this can happen:
>
> 1) In the PHY
> 2) Extra long lines on the PCB
> 3) In the MAC
>
> Generally, 1) is used, and controlled via phy-mode. A value of
> PHY_INTERFACE_MODE_RGMII_ID passed to the PHY driver means it will add
> these delays.
>
> You don't want both the MAC and the PHY adding delays.
>
These are set to enable MAC transmit clock delay set for Tx and Rx for
iomux group.
>
>     Andrew

Thanks
-Anand