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From:   Samin Guo <samin.guo@starfivetech.com>
To:     <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <netdev@vger.kernel.org>, Peter Geis <pgwipeout@gmail.com>,
        Frank <Frank.Sae@motor-comm.com>
CC:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Andrew Lunn <andrew@lunn.ch>,
        "Heiner Kallweit" <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "Samin Guo" <samin.guo@starfivetech.com>,
        Yanhong Wang <yanhong.wang@starfivetech.com>
Subject: [PATCH v3 2/2] net: phy: motorcomm: Add pad drive strength cfg support
Date:   Fri, 26 May 2023 17:05:02 +0800
Message-ID: <20230526090502.29835-3-samin.guo@starfivetech.com>
In-Reply-To: <20230526090502.29835-1-samin.guo@starfivetech.com>
References: <20230526090502.29835-1-samin.guo@starfivetech.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

The motorcomm phy (YT8531) supports the ability to adjust the drive
strength of the rx_clk/rx_data, and the default strength may not be
suitable for all boards. So add configurable options to better match
the boards.(e.g. StarFive VisionFive 2)

Signed-off-by: Samin Guo <samin.guo@starfivetech.com>
---
 drivers/net/phy/motorcomm.c | 46 +++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/net/phy/motorcomm.c b/drivers/net/phy/motorcomm.c
index 2fa5a90e073b..e5d6b491046e 100644
--- a/drivers/net/phy/motorcomm.c
+++ b/drivers/net/phy/motorcomm.c
@@ -236,6 +236,15 @@
  */
 #define YTPHY_WCR_TYPE_PULSE			BIT(0)
 
+#define YTPHY_PAD_DRIVE_STRENGTH_REG		0xA010
+#define YT8531_RGMII_RXC_DS_DEFAULT		0x3
+#define YT8531_RGMII_RXC_DS_MAX			0x7
+#define YT8531_RGMII_RXC_DS			GENMASK(15, 13)
+#define YT8531_RGMII_RXD_DS_DEFAULT		0x3
+#define YT8531_RGMII_RXD_DS_MAX			0x7
+#define YT8531_RGMII_RXD_DS_LOW			GENMASK(5, 4) /* Bit 1/0 of rxd_ds */
+#define YT8531_RGMII_RXD_DS_HI			BIT(12) /* Bit 2 of rxd_ds */
+
 #define YTPHY_SYNCE_CFG_REG			0xA012
 #define YT8521_SCR_SYNCE_ENABLE			BIT(5)
 /* 1b0 output 25m clock
@@ -1494,6 +1503,7 @@ static int yt8521_config_init(struct phy_device *phydev)
 static int yt8531_config_init(struct phy_device *phydev)
 {
 	struct device_node *node = phydev->mdio.dev.of_node;
+	u32 ds, val;
 	int ret;
 
 	ret = ytphy_rgmii_clk_delay_config_with_lock(phydev);
@@ -1518,6 +1528,42 @@ static int yt8531_config_init(struct phy_device *phydev)
 			return ret;
 	}
 
+	ds = YT8531_RGMII_RXC_DS_DEFAULT;
+	if (!of_property_read_u32(node, "motorcomm,rx-clk-driver-strength", &val)) {
+		if (val > YT8531_RGMII_RXC_DS_MAX)
+			return -EINVAL;
+
+		ds = val;
+	}
+
+	ret = ytphy_modify_ext_with_lock(phydev,
+					 YTPHY_PAD_DRIVE_STRENGTH_REG,
+					 YT8531_RGMII_RXC_DS,
+					 FIELD_PREP(YT8531_RGMII_RXC_DS, ds));
+	if (ret < 0)
+		return ret;
+
+	ds = FIELD_PREP(YT8531_RGMII_RXD_DS_LOW, YT8531_RGMII_RXD_DS_DEFAULT);
+	if (!of_property_read_u32(node, "motorcomm,rx-data-driver-strength", &val)) {
+		if (val > YT8531_RGMII_RXD_DS_MAX)
+			return -EINVAL;
+
+		if (val > FIELD_MAX(YT8531_RGMII_RXD_DS_LOW)) {
+			ds = val & FIELD_MAX(YT8531_RGMII_RXD_DS_LOW);
+			ds = FIELD_PREP(YT8531_RGMII_RXD_DS_LOW, ds);
+			ds |= YT8531_RGMII_RXD_DS_HI;
+		} else {
+			ds = FIELD_PREP(YT8531_RGMII_RXD_DS_LOW, val);
+		}
+	}
+
+	ret = ytphy_modify_ext_with_lock(phydev,
+					 YTPHY_PAD_DRIVE_STRENGTH_REG,
+					 YT8531_RGMII_RXD_DS_LOW | YT8531_RGMII_RXD_DS_HI,
+					 ds);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
-- 
2.17.1