From 422b5233b607476ac7176bfa2a101b9a103d7653 Mon Sep 17 00:00:00 2001 From: Frank Wunderlich Date: Tue, 26 May 2026 17:32:38 +0200 Subject: net: pcs: pcs-mtk-lynxi: fix bpi-r3 serdes configuration Commit 8871389da151 introduces common pcs dts properties which writes rx=normal,tx=normal polarity to register SGMSYS_QPHY_WRAP_CTRL of switch. This is initialized with tx-bit set and so change inverts polarity compared to before. It looks like mt7531 has tx polarity inverted in hardware and set tx-bit by default to restore the normal polarity. The MT7531 datasheet quite clearly states: Register 000050EC QPHY_WRAP_CTRL -- QPHY wrapper control Reset value: 0x00000501 BIT 1 RX_BIT_POLARITY -- RX bit polarity control 1'b0: normal 1'b1: inverted BIT 0 TX_BIT_POLARITY -- TX bit polarity control (TX default inversed in MT7531) 1'b0: normal 1'b1: inverted Till this patch the register write was only called when mediatek,pnswap property was set which cannot be done for switch because the fw-node param was always NULL from switch driver in the mtk_pcs_lynxi_create call. Do not configure switch side like it's done before. Fixes: 8871389da151 ("net: pcs: pcs-mtk-lynxi: deprecate "mediatek,pnswap"") Signed-off-by: Frank Wunderlich Reviewed-by: Vladimir Oltean Link: https://patch.msgid.link/20260526153239.30194-1-linux@fw-web.de Signed-off-by: Jakub Kicinski --- drivers/net/pcs/pcs-mtk-lynxi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/pcs/pcs-mtk-lynxi.c b/drivers/net/pcs/pcs-mtk-lynxi.c index c12f8087af9b..a753bd88cbc2 100644 --- a/drivers/net/pcs/pcs-mtk-lynxi.c +++ b/drivers/net/pcs/pcs-mtk-lynxi.c @@ -129,6 +129,9 @@ static int mtk_pcs_config_polarity(struct mtk_pcs_lynxi *mpcs, unsigned int val = 0; int ret; + if (!fwnode) + return 0; + if (fwnode_property_read_bool(fwnode, "mediatek,pnswap")) default_pol = PHY_POL_INVERT; -- cgit v1.2.3