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From:   Alexander Couzens <lynxis@fe80.eu>
To:     Felix Fietkau <nbd@nbd.name>, John Crispin <john@phrozen.org>,
        Sean Wang <sean.wang@mediatek.com>,
        Mark Lee <Mark-MC.Lee@mediatek.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Russell King <linux@armlinux.org.uk>, netdev@vger.kernel.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Daniel Golle <daniel@makrotopia.org>,
        Alexander Couzens <lynxis@fe80.eu>
Subject: [PATCH 1/4] net: mediatek: sgmii: fix powering up the SGMII phy
Date:   Sun, 21 Aug 2022 00:45:35 +0200
Message-Id: <20220820224538.59489-2-lynxis@fe80.eu>
In-Reply-To: <20220820224538.59489-1-lynxis@fe80.eu>
References: <20220820224538.59489-1-lynxis@fe80.eu>
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There are cases when the SGMII_PHYA_PWD register contains 0x9 which
prevents SGMII from working. The SGMII still shows link but no traffic
can flow. Writing 0x0 to the PHYA_PWD register fix the issue. 0x0 was
taken from a good working state of the SGMII interface.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
---
 drivers/net/ethernet/mediatek/mtk_sgmii.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index 736839c84130..a01bb20ea957 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -36,9 +36,7 @@ static int mtk_pcs_setup_mode_an(struct mtk_pcs *mpcs)
 	val |= SGMII_AN_RESTART;
 	regmap_write(mpcs->regmap, SGMSYS_PCS_CONTROL_1, val);
 
-	regmap_read(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, &val);
-	val &= ~SGMII_PHYA_PWD;
-	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, val);
+	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);
 
 	return 0;
 
@@ -70,9 +68,7 @@ static int mtk_pcs_setup_mode_force(struct mtk_pcs *mpcs,
 	regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
 
 	/* Release PHYA power down state */
-	regmap_read(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, &val);
-	val &= ~SGMII_PHYA_PWD;
-	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, val);
+	regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);
 
 	return 0;
 }
-- 
2.35.1