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From:   Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
To:     Sean Wang <sean.wang@mediatek.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Russell King <linux@armlinux.org.uk>, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Subject: [PATCH net] net: dsa: mt7530: setup core clock even in TRGMII mode
Date:   Wed, 10 Mar 2021 17:21:08 -0800
Message-Id: <20210311012108.7190-1-ilya.lipnitskiy@gmail.com>
MIME-Version: 1.0
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A recent change to MIPS ralink reset logic made it so mt7530 actually
resets the switch on platforms such as mt7621 (where bit 2 is the reset
line for the switch). That exposed an issue where the switch would not
function properly in TRGMII mode after a reset.

Reconfigure core clock in TRGMII mode to fix the issue.

Tested on Ubiquiti ER-X (MT7621) with TRGMII mode enabled.

Fixes: 3f9ef7785a9c ("MIPS: ralink: manage low reset lines")
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
---
 drivers/net/dsa/mt7530.c | 52 +++++++++++++++++++---------------------
 1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index f06f5fa2f898..9871d7cff93a 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -436,34 +436,32 @@ mt7530_pad_clk_setup(struct dsa_switch *ds, phy_interface_t interface)
 			     TD_DM_DRVP(8) | TD_DM_DRVN(8));
 
 	/* Setup core clock for MT7530 */
-	if (!trgint) {
-		/* Disable MT7530 core clock */
-		core_clear(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
-
-		/* Disable PLL, since phy_device has not yet been created
-		 * provided for phy_[read,write]_mmd_indirect is called, we
-		 * provide our own core_write_mmd_indirect to complete this
-		 * function.
-		 */
-		core_write_mmd_indirect(priv,
-					CORE_GSWPLL_GRP1,
-					MDIO_MMD_VEND2,
-					0);
-
-		/* Set core clock into 500Mhz */
-		core_write(priv, CORE_GSWPLL_GRP2,
-			   RG_GSWPLL_POSDIV_500M(1) |
-			   RG_GSWPLL_FBKDIV_500M(25));
+	/* Disable MT7530 core clock */
+	core_clear(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
 
-		/* Enable PLL */
-		core_write(priv, CORE_GSWPLL_GRP1,
-			   RG_GSWPLL_EN_PRE |
-			   RG_GSWPLL_POSDIV_200M(2) |
-			   RG_GSWPLL_FBKDIV_200M(32));
-
-		/* Enable MT7530 core clock */
-		core_set(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
-	}
+	/* Disable PLL, since phy_device has not yet been created
+	 * provided for phy_[read,write]_mmd_indirect is called, we
+	 * provide our own core_write_mmd_indirect to complete this
+	 * function.
+	 */
+	core_write_mmd_indirect(priv,
+				CORE_GSWPLL_GRP1,
+				MDIO_MMD_VEND2,
+				0);
+
+	/* Set core clock into 500Mhz */
+	core_write(priv, CORE_GSWPLL_GRP2,
+		   RG_GSWPLL_POSDIV_500M(1) |
+		   RG_GSWPLL_FBKDIV_500M(25));
+
+	/* Enable PLL */
+	core_write(priv, CORE_GSWPLL_GRP1,
+		   RG_GSWPLL_EN_PRE |
+		   RG_GSWPLL_POSDIV_200M(2) |
+		   RG_GSWPLL_FBKDIV_200M(32));
+
+	/* Enable MT7530 core clock */
+	core_set(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
 
 	/* Setup the MT7530 TRGMII Tx Clock */
 	core_set(priv, CORE_TRGMII_GSW_CLK_CG, REG_GSWCK_EN);
-- 
2.30.2