[PATCH v5 net-next 5/5] drivers/net/phy: add driver for the onsemi NCN26000 10BASE-T1S PHY

Piergiorgio Beruto
2022-12-07T00:03:05Z

This patch adds support for the onsemi NCN26000 10BASE-T1S industrial
Ethernet PHY. The driver supports Point-to-Multipoint operation without
auto-negotiation and with link control handling. The PHY also features
PLCA for improving performance in P2MP mode.

Signed-off-by: Piergiorgio Beruto <piergiorgio.beruto@gmail.com>
---
MAINTAINERS | 7 ++
drivers/net/phy/Kconfig | 7 ++
drivers/net/phy/Makefile | 1 +
drivers/net/phy/ncn26000.c | 201 +++++++++++++++++++++++++++++++++++++
4 files changed, 216 insertions(+)
create mode 100644 drivers/net/phy/ncn26000.c

diff --git a/MAINTAINERS b/MAINTAINERS
index ed626cbdf5af..09f0bfa3ae64 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15357,6 +15357,13 @@ L: linux-mips@vger.kernel.org
S: Maintained
F: arch/mips/boot/dts/ralink/omega2p.dts

+ONSEMI ETHERNET PHY DRIVERS
+M: Piergiorgio Beruto <piergiorgio.beruto@gmail.com>
+L: netdev@vger.kernel.org
+S: Supported
+W: http://www.onsemi.com
+F: drivers/net/phy/ncn*
+
OP-TEE DRIVER
M: Jens Wiklander <jens.wiklander@linaro.org>
L: op-tee@lists.trustedfirmware.org
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index af00cf44cd97..7c466830c611 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -267,6 +267,13 @@ config NATIONAL_PHY
help
Currently supports the DP83865 PHY.

+config NCN26000_PHY
+ tristate "onsemi 10BASE-T1S Ethernet PHY"
+ help
+ Adds support for the onsemi 10BASE-T1S Ethernet PHY.
+ Currently supports the NCN26000 10BASE-T1S Industrial PHY
+ with MII interface.
+
config NXP_C45_TJA11XX_PHY
tristate "NXP C45 TJA11XX PHYs"
depends on PTP_1588_CLOCK_OPTIONAL
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index f7138d3c896b..b5138066ba04 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_MICROCHIP_T1_PHY) += microchip_t1.o
obj-$(CONFIG_MICROSEMI_PHY) += mscc/
obj-$(CONFIG_MOTORCOMM_PHY) += motorcomm.o
obj-$(CONFIG_NATIONAL_PHY) += national.o
+obj-$(CONFIG_NCN26000_PHY) += ncn26000.o
obj-$(CONFIG_NXP_C45_TJA11XX_PHY) += nxp-c45-tja11xx.o
obj-$(CONFIG_NXP_TJA11XX_PHY) += nxp-tja11xx.o
obj-$(CONFIG_QSEMI_PHY) += qsemi.o
diff --git a/drivers/net/phy/ncn26000.c b/drivers/net/phy/ncn26000.c
new file mode 100644
index 000000000000..d3c0a7420ea8
--- /dev/null
+++ b/drivers/net/phy/ncn26000.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Driver for the onsemi 10BASE-T1S NCN26000 PHYs family.
+ *
+ * Copyright 2022 onsemi
+ */
+#include <linux/kernel.h>
+#include <linux/bitfield.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mii.h>
+#include <linux/phy.h>
+
+#include "mdio-open-alliance.h"
+
+#define PHY_ID_NCN26000 0x180FF5A1
+
+#define NCN26000_REG_IRQ_CTL 16
+#define NCN26000_REG_IRQ_STATUS 17
+
+// the NCN26000 maps link_ctrl to BMCR_ANENABLE
+#define NCN26000_BCMR_LINK_CTRL_BIT BMCR_ANENABLE
+
+// the NCN26000 maps link_status to BMSR_ANEGCOMPLETE
+#define NCN26000_BMSR_LINK_STATUS_BIT BMSR_ANEGCOMPLETE
+
+#define NCN26000_IRQ_LINKST_BIT BIT(0)
+#define NCN26000_IRQ_PLCAST_BIT BIT(1)
+#define NCN26000_IRQ_LJABBER_BIT BIT(2)
+#define NCN26000_IRQ_RJABBER_BIT BIT(3)
+#define NCN26000_IRQ_PLCAREC_BIT BIT(4)
+#define NCN26000_IRQ_PHYSCOL_BIT BIT(5)
+
+#define TO_TMR_DEFAULT 32
+
+struct ncn26000_priv {
+ u16 enabled_irqs;
+};
+
+// driver callbacks
+
+static int ncn26000_config_init(struct phy_device *phydev)
+{
+ /* HW bug workaround: the default value of the PLCA TO_TIMER should be
+ * 32, where the current version of NCN26000 reports 24. This will be
+ * fixed in future PHY versions. For the time being, we force the
+ * correct default here.
+ */
+ return phy_write_mmd(phydev, MDIO_MMD_VEND2, MDIO_OATC14_PLCA_TOTMR,
+ TO_TMR_DEFAULT);
+}
+
+static int ncn26000_config_aneg(struct phy_device *phydev)
+{
+ // Note: the NCN26000 supports only P2MP link mode. Therefore, AN is not
+ // supported. However, this function is invoked by phylib to enable the
+ // PHY, regardless of the AN support.
+ phydev->mdix_ctrl = ETH_TP_MDI_AUTO;
+ phydev->mdix = ETH_TP_MDI;
+
+ // bring up the link
+ return phy_write(phydev, MII_BMCR, NCN26000_BCMR_LINK_CTRL_BIT);
+}
+
+static int ncn26000_get_features(struct phy_device *phydev)
+{
+ linkmode_zero(phydev->supported);
+ linkmode_set_bit(ETHTOOL_LINK_MODE_MII_BIT, phydev->supported);
+
+ linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT1S_P2MP_Half_BIT,
+ phydev->supported);
+
+ linkmode_copy(phydev->advertising, phydev->supported);
+ return 0;
+}
+
+static int ncn26000_read_status(struct phy_device *phydev)
+{
+ // The NCN26000 reports NCN26000_LINK_STATUS_BIT if the link status of
+ // the PHY is up. It further reports the logical AND of the link status
+ // and the PLCA status in the BMSR_LSTATUS bit.
+ int ret;
+
+ /* The link state is latched low so that momentary link
+ * drops can be detected. Do not double-read the status
+ * in polling mode to detect such short link drops except
+ * the link was already down.
+ */
+ if (!phy_polling_mode(phydev) || !phydev->link) {
+ ret = phy_read(phydev, MII_BMSR);
+ if (ret < 0)
+ return ret;
+ else if (ret & NCN26000_BMSR_LINK_STATUS_BIT)
+ goto upd_link;
+ }
+
+ ret = phy_read(phydev, MII_BMSR);
+ if (unlikely(ret < 0))
+ return ret;
+
+upd_link:
+ // update link status
+ if (ret & NCN26000_BMSR_LINK_STATUS_BIT) {
+ phydev->link = 1;
+ phydev->pause = 0;
+ phydev->duplex = DUPLEX_HALF;
+ phydev->speed = SPEED_10;
+ } else {
+ phydev->link = 0;
+ phydev->duplex = DUPLEX_UNKNOWN;
+ phydev->speed = SPEED_UNKNOWN;
+ }
+
+ return 0;
+}
+
+static irqreturn_t ncn26000_handle_interrupt(struct phy_device *phydev)
+{
+ const struct ncn26000_priv *const priv = phydev->priv;
+ int ret;
+
+ // read and aknowledge the IRQ status register
+ ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
+
+ if (unlikely(ret < 0) || (ret & priv->enabled_irqs) == 0)
+ return IRQ_NONE;
+
+ phy_trigger_machine(phydev);
+ return IRQ_HANDLED;
+}
+
+static int ncn26000_config_intr(struct phy_device *phydev)
+{
+ int ret;
+ struct ncn26000_priv *priv = phydev->priv;
+
+ if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+ // acknowledge IRQs
+ ret = phy_read(phydev, NCN26000_REG_IRQ_STATUS);
+ if (ret < 0)
+ return ret;
+
+ // get link status notifications
+ priv->enabled_irqs = NCN26000_IRQ_LINKST_BIT;
+ } else {
+ // disable all IRQs
+ priv->enabled_irqs = 0;
+ }
+
+ ret = phy_write(phydev, NCN26000_REG_IRQ_CTL, priv->enabled_irqs);
+ if (ret != 0)
+ return ret;
+
+ return 0;
+}
+
+static int ncn26000_probe(struct phy_device *phydev)
+{
+ struct device *dev = &phydev->mdio.dev;
+ struct ncn26000_priv *priv;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ phydev->priv = priv;
+
+ return 0;
+}
+
+static struct phy_driver ncn26000_driver[] = {
+ {
+ PHY_ID_MATCH_MODEL(PHY_ID_NCN26000),
+ .name = "NCN26000",
+ .probe = ncn26000_probe,
+ .get_features = ncn26000_get_features,
+ .config_init = ncn26000_config_init,
+ .config_intr = ncn26000_config_intr,
+ .config_aneg = ncn26000_config_aneg,
+ .read_status = ncn26000_read_status,
+ .handle_interrupt = ncn26000_handle_interrupt,
+ .get_plca_cfg = genphy_c45_plca_get_cfg,
+ .set_plca_cfg = genphy_c45_plca_set_cfg,
+ .get_plca_status = genphy_c45_plca_get_status,
+ .soft_reset = genphy_soft_reset,
+ },
+};
+
+module_phy_driver(ncn26000_driver);
+
+static struct mdio_device_id __maybe_unused ncn26000_tbl[] = {
+ { PHY_ID_MATCH_MODEL(PHY_ID_NCN26000) },
+ { }
+};
+
+MODULE_DEVICE_TABLE(mdio, ncn26000_tbl);
+
+MODULE_AUTHOR("Piergiorgio Beruto");
+MODULE_DESCRIPTION("onsemi 10BASE-T1S PHY driver");
+MODULE_LICENSE("Dual BSD/GPL");
--
2.35.1