From b66105968b8c37c26a75b9da9281cbc1c8f73594 Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Sun, 22 Jan 2023 23:58:36 +0000
Subject: [PATCH] net: ethernet: mtk_eth_soc: reset PCS state
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Reset PCS state when changing interface mode.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Tested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 ++++
 drivers/net/ethernet/mediatek/mtk_sgmii.c   | 4 ++++
 2 files changed, 8 insertions(+)

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -529,6 +529,10 @@
 #define SGMII_SEND_AN_ERROR_EN		BIT(11)
 #define SGMII_IF_MODE_MASK		GENMASK(5, 1)
 
+/* Register to reset SGMII design */
+#define SGMII_RESERVED_0	0x34
+#define SGMII_SW_RESET		BIT(0)
+
 /* Register to set SGMII speed, ANA RG_ Control Signals III*/
 #define SGMSYS_ANA_RG_CS3	0x2028
 #define RG_PHY_SPEED_MASK	(BIT(2) | BIT(3))
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -90,6 +90,10 @@ static int mtk_pcs_config(struct phylink
 		regmap_update_bits(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL,
 				   SGMII_PHYA_PWD, SGMII_PHYA_PWD);
 
+		/* Reset SGMII PCS state */
+		regmap_update_bits(mpcs->regmap, SGMII_RESERVED_0,
+				   SGMII_SW_RESET, SGMII_SW_RESET);
+
 		mpcs->interface = interface;
 	}
 
