[PATCH net-next] net: ethernet: mtk_eth_soc: add support for MT7988 internal 2.5G PHY

[Daniel Golle]

On Fri, Apr 25, 2025 at 10:51:18PM +0100, Daniel Golle wrote:
> The MediaTek MT7988 SoC comes with an single built-in Ethernet PHY
> supporting 2500Base-T/1000Base-T/100Base-TX/10Base-T link partners in
> addition to the built-in MT7531-like 1GE switch. The built-in PHY only
> supports full duplex.
> 
> Add muxes allowing to select GMAC2->2.5G PHY path and add basic support
> for XGMAC as the built-in 2.5G PHY is internally connected via XGMII.
> The XGMAC features will also be used by 5GBase-R, 10GBase-R and USXGMII
> SerDes modes which are going to be added once support for standalone PCS
> drivers is in place.
> 
> In order to make use of the built-in 2.5G PHY the appropriate PHY driver
> as well as (proprietary) PHY firmware has to be present as well.
> 
> Signed-off-by: Daniel Golle <daniel at makrotopia.org>
> ---
> [...]
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> index 88ef2e9c50fc..e3a8b24dd3d3 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> [...]
> @@ -587,6 +603,10 @@
>  #define GEPHY_MAC_SEL          BIT(1)
>  
>  /* Top misc registers */
> +#define TOP_MISC_NETSYS_PCS_MUX	0x84

This offset still assumes topmisc syscon to start at 0x11d10000.
If the pending series[1] adding that syscon at 0x11d10084 gets merged
first, this offset will have to be changed to
#define TOP_MISC_NETSYS_PCS_MUX	0x0

[1]: https://patchwork.kernel.org/project/linux-mediatek/patch/20250422132438.15735-8-linux@fw-web.de/