Messages in this thread | | | Date | Fri, 3 Feb 2023 16:18:40 +0200 | From | Vladimir Oltean <> | Subject | Re: [PATCH 1/9] net: ethernet: mtk_eth_soc: add support for MT7981 SoC |
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On Fri, Feb 03, 2023 at 07:00:21AM +0000, Daniel Golle wrote: > The MediaTek MT7981 SoC comes two 1G/2.5G SGMII, just like MT7986. > > In addition MT7981 comes with a built-in 1000Base-T PHY which can be > used with GMAC1. > > As many MT7981 boards make use of swapping SGMII phase and neutral, add > new device-tree attribute 'mediatek,pn_swap' to support them. > > Signed-off-by: Daniel Golle <daniel@makrotopia.org> > ---
Phase and neutral? What is this, a power plug? Since SGMII uses differential signaling, I wonder if this isn't about the polarity of the TX lane (which pin carries the Positive signal and which the Negative one).
I think there is room for a more general device tree property name than "mediatek,pn_swap". The Designware XPCS also supports this, see DW_VR_MII_DIG_CTRL2_TX_POL_INV and the comments in nxp_sja1105_sgmii_pma_config().
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