[PATCH net-next v2 2/2] net: phy: dp83td510: Add support for the DP83TD510 Ethernet PHY

[Oleksij Rempel <o.rempel@pengutronix.de>]

The DP83TD510E is an ultra-low power Ethernet physical layer transceiver
that supports 10M single pair cable.

This driver was tested with NXP SJA1105, STMMAC and ASIX AX88772B USB Ethernet
controller.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/phy/Kconfig     |   6 +
 drivers/net/phy/Makefile    |   1 +
 drivers/net/phy/dp83td510.c | 272 ++++++++++++++++++++++++++++++++++++
 3 files changed, 279 insertions(+)
 create mode 100644 drivers/net/phy/dp83td510.c

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index bbbf6c07ea53..9fee639ee5c8 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -342,6 +342,12 @@ config DP83869_PHY
 	  Currently supports the DP83869 PHY.  This PHY supports copper and
 	  fiber connections.
 
+config DP83TD510_PHY
+	tristate "Texas Instruments DP83TD510 Ethernet 10Base-T1L PHY"
+	help
+	  Support for the DP83TD510 Ethernet 10Base-T1L PHY. This PHY supports
+	  a 10M single pair Ethernet connection for up to 1000 meter cable.
+
 config VITESSE_PHY
 	tristate "Vitesse PHYs"
 	help
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index b82651b57043..b12b1d86fc99 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_DP83848_PHY)	+= dp83848.o
 obj-$(CONFIG_DP83867_PHY)	+= dp83867.o
 obj-$(CONFIG_DP83869_PHY)	+= dp83869.o
 obj-$(CONFIG_DP83TC811_PHY)	+= dp83tc811.o
+obj-$(CONFIG_DP83TD510_PHY)	+= dp83td510.o
 obj-$(CONFIG_FIXED_PHY)		+= fixed_phy.o
 obj-$(CONFIG_ICPLUS_PHY)	+= icplus.o
 obj-$(CONFIG_INTEL_XWAY_PHY)	+= intel-xway.o
diff --git a/drivers/net/phy/dp83td510.c b/drivers/net/phy/dp83td510.c
new file mode 100644
index 000000000000..8f6b0cbed599
--- /dev/null
+++ b/drivers/net/phy/dp83td510.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Driver for the Texas Instruments DP83TD510 PHY
+ * Copyright (c) 2022 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define DP83TD510E_PHY_ID			0x20000181
+
+/* MDIO_MMD_VEND2 registers */
+#define DP83TD510E_PHY_STS			0x10
+#define DP83TD510E_STS_MII_INT			BIT(7)
+#define DP83TD510E_LINK_STATUS			BIT(0)
+
+#define DP83TD510E_GEN_CFG			0x11
+#define DP83TD510E_GENCFG_INT_POLARITY		BIT(3)
+#define DP83TD510E_GENCFG_INT_EN		BIT(1)
+#define DP83TD510E_GENCFG_INT_OE		BIT(0)
+
+#define DP83TD510E_INTERRUPT_REG_1		0x12
+#define DP83TD510E_INT1_LINK			BIT(13)
+#define DP83TD510E_INT1_LINK_EN			BIT(5)
+
+#define DP83TD510E_AN_STAT_1			0x60c
+#define DP83TD510E_MASTER_SLAVE_RESOL_FAIL	BIT(15)
+
+static int dp83td510_config_intr(struct phy_device *phydev)
+{
+	int ret;
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		/* Clear any pending interrupts */
+		ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TD510E_PHY_STS,
+				    0x0);
+		if (ret)
+			return ret;
+
+		ret = phy_write_mmd(phydev, MDIO_MMD_VEND2,
+				    DP83TD510E_INTERRUPT_REG_1,
+				    DP83TD510E_INT1_LINK_EN);
+		if (ret)
+			return ret;
+
+		ret = phy_set_bits_mmd(phydev, MDIO_MMD_VEND2,
+				       DP83TD510E_GEN_CFG,
+				       DP83TD510E_GENCFG_INT_POLARITY |
+				       DP83TD510E_GENCFG_INT_EN |
+				       DP83TD510E_GENCFG_INT_OE);
+	} else {
+		ret = phy_write_mmd(phydev, MDIO_MMD_VEND2,
+				    DP83TD510E_INTERRUPT_REG_1, 0x0);
+		if (ret)
+			return ret;
+
+		ret = phy_clear_bits_mmd(phydev, MDIO_MMD_VEND2,
+					 DP83TD510E_GEN_CFG,
+					 DP83TD510E_GENCFG_INT_EN);
+		if (ret)
+			return ret;
+
+		/* Clear any pending interrupts */
+		ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TD510E_PHY_STS,
+				    0x0);
+	}
+
+	return ret;
+}
+
+static irqreturn_t dp83td510_handle_interrupt(struct phy_device *phydev)
+{
+	int  ret;
+
+	ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, DP83TD510E_PHY_STS);
+	if (ret < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	} else if (!(ret & DP83TD510E_STS_MII_INT)) {
+		return IRQ_NONE;
+	}
+
+	/* Read the current enabled interrupts */
+	ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, DP83TD510E_INTERRUPT_REG_1);
+	if (ret < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	} else if (!(ret & DP83TD510E_INT1_LINK_EN) ||
+		   !(ret & DP83TD510E_INT1_LINK)) {
+		return IRQ_NONE;
+	}
+
+	phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+static int dp83td510_read_status(struct phy_device *phydev)
+{
+	u16 phy_sts;
+	int ret, cfg;
+
+	phydev->speed = SPEED_UNKNOWN;
+	phydev->duplex = DUPLEX_UNKNOWN;
+	phydev->pause = 0;
+	phydev->asym_pause = 0;
+	phydev->master_slave_get = MASTER_SLAVE_CFG_UNKNOWN;
+	phydev->master_slave_state = MASTER_SLAVE_STATE_UNKNOWN;
+	linkmode_zero(phydev->lp_advertising);
+
+	phy_sts = phy_read(phydev, DP83TD510E_PHY_STS);
+
+	phydev->link = !!(phy_sts & DP83TD510E_LINK_STATUS);
+	if (phydev->link) {
+		/* This PHY supports only one link mode: 10BaseT1L_Full */
+		phydev->duplex = DUPLEX_FULL;
+		phydev->speed = SPEED_10;
+
+		if (phydev->autoneg == AUTONEG_ENABLE) {
+			ret = genphy_c45_read_lpa(phydev);
+			if (ret)
+				return ret;
+
+			phy_resolve_aneg_linkmode(phydev);
+		}
+	}
+
+	if (phydev->autoneg == AUTONEG_DISABLE) {
+		ret = phy_read_mmd(phydev, MDIO_MMD_PMAPMD,
+				   MDIO_PMA_PMD_BT1_CTRL);
+		if (ret < 0)
+			return ret;
+
+		if (ret & MDIO_PMA_PMD_BT1_CTRL_CFG_MST) {
+			phydev->master_slave_get =
+				MASTER_SLAVE_CFG_MASTER_FORCE;
+			if (phydev->link)
+				phydev->master_slave_state =
+					MASTER_SLAVE_STATE_MASTER;
+		} else {
+			phydev->master_slave_get = MASTER_SLAVE_CFG_SLAVE_FORCE;
+			if (phydev->link)
+				phydev->master_slave_state =
+					MASTER_SLAVE_STATE_SLAVE;
+		}
+	} else {
+		ret = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_AN_T1_ADV_L);
+		if (ret < 0)
+			return ret;
+
+		cfg = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_AN_T1_ADV_M);
+		if (cfg < 0)
+			return cfg;
+
+		if (ret & MDIO_AN_T1_ADV_L_FORCE_MS) {
+			if (cfg & MDIO_AN_T1_ADV_M_MST)
+				phydev->master_slave_get =
+					MASTER_SLAVE_CFG_MASTER_FORCE;
+			else
+				phydev->master_slave_get =
+					MASTER_SLAVE_CFG_SLAVE_FORCE;
+		} else {
+			if (cfg & MDIO_AN_T1_ADV_M_MST)
+				phydev->master_slave_get =
+					MASTER_SLAVE_CFG_MASTER_PREFERRED;
+			else
+				phydev->master_slave_get =
+					MASTER_SLAVE_CFG_SLAVE_PREFERRED;
+		}
+
+		ret = phy_read_mmd(phydev, MDIO_MMD_VEND2,
+				   DP83TD510E_AN_STAT_1);
+		if (ret < 0)
+			return ret;
+
+		if (ret & DP83TD510E_MASTER_SLAVE_RESOL_FAIL)
+			phydev->master_slave_state = MASTER_SLAVE_STATE_ERR;
+	}
+
+	return 0;
+}
+
+static int dp83td510_config_master_slave(struct phy_device *phydev)
+{
+	int ctl = 0;
+
+	switch (phydev->master_slave_set) {
+	case MASTER_SLAVE_CFG_MASTER_PREFERRED:
+	case MASTER_SLAVE_CFG_MASTER_FORCE:
+		ctl = MDIO_PMA_PMD_BT1_CTRL_CFG_MST;
+		break;
+	case MASTER_SLAVE_CFG_SLAVE_FORCE:
+	case MASTER_SLAVE_CFG_SLAVE_PREFERRED:
+		break;
+	case MASTER_SLAVE_CFG_UNKNOWN:
+	case MASTER_SLAVE_CFG_UNSUPPORTED:
+		return 0;
+	default:
+		phydev_warn(phydev, "Unsupported Master/Slave mode\n");
+		return -EOPNOTSUPP;
+	}
+
+	return phy_modify_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PMA_PMD_BT1_CTRL,
+			     MDIO_PMA_PMD_BT1_CTRL_CFG_MST, ctl);
+}
+
+static int dp83td510_config_aneg(struct phy_device *phydev)
+{
+	bool changed = false;
+	int ctl = 0;
+	int ret;
+
+	ret = dp83td510_config_master_slave(phydev);
+	if (ret < 0)
+		return ret;
+
+	if (phydev->autoneg == AUTONEG_DISABLE)
+		return genphy_c45_an_disable_aneg(phydev);
+
+	ret = genphy_c45_an_config_aneg(phydev);
+	if (ret < 0)
+		return ret;
+	if (ret > 0)
+		changed = true;
+
+	return genphy_c45_check_and_restart_aneg(phydev, changed);
+}
+
+static int dp83td510_get_features(struct phy_device *phydev)
+{
+	/* This PHY can't respond on MDIO bus if no RMII clock is enabled.
+	 * In case RMII mode is used (most meaningful mode for this PHY) and
+	 * the PHY do not have own XTAL, and CLK providing MAC is not probed,
+	 * we won't be able to read all needed ability registers.
+	 * So provide it manually.
+	 */
+
+	linkmode_set_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_Pause_BIT, phydev->supported);
+	linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT1L_Full_BIT,
+			 phydev->supported);
+
+	return 0;
+}
+
+static struct phy_driver dp83td510_driver[] = {
+{
+	PHY_ID_MATCH_MODEL(DP83TD510E_PHY_ID),
+	.name		= "TI DP83TD510E",
+
+	.config_aneg	= dp83td510_config_aneg,
+	.read_status	= dp83td510_read_status,
+	.get_features	= dp83td510_get_features,
+	.config_intr	= dp83td510_config_intr,
+	.handle_interrupt = dp83td510_handle_interrupt,
+
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+} };
+module_phy_driver(dp83td510_driver);
+
+static struct mdio_device_id __maybe_unused dp83td510_tbl[] = {
+	{ PHY_ID_MATCH_MODEL(DP83TD510E_PHY_ID) },
+	{ }
+};
+MODULE_DEVICE_TABLE(mdio, dp83td510_tbl);
+
+MODULE_DESCRIPTION("Texas Instruments DP83TD510E PHY driver");
+MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>");
+MODULE_LICENSE("GPL v2");
-- 
2.30.2