1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/net/phy/ax88796b.c b/drivers/net/phy/ax88796b.c
new file mode 100644
index 0000000000..0f1e617a26
--- /dev/null
+++ b/drivers/net/phy/ax88796b.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Driver for Asix PHYs
+ *
+ * Author: Michael Schmitz <schmitzmic@gmail.com>
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mii.h>
+#include <linux/phy.h>
+
+#define PHY_ID_ASIX_AX88772A		0x003b1861
+#define PHY_ID_ASIX_AX88772C		0x003b1881
+#define PHY_ID_ASIX_AX88796B		0x003b1841
+
+MODULE_DESCRIPTION("Asix PHY driver");
+MODULE_AUTHOR("Michael Schmitz <schmitzmic@gmail.com>");
+MODULE_LICENSE("GPL");
+
+/**
+ * asix_soft_reset - software reset the PHY via BMCR_RESET bit
+ * @phydev: target phy_device struct
+ *
+ * Description: Perform a software PHY reset using the standard
+ * BMCR_RESET bit and poll for the reset bit to be cleared.
+ * Toggle BMCR_RESET bit off to accommodate broken AX8796B PHY implementation
+ * such as used on the Individual Computers' X-Surf 100 Zorro card.
+ *
+ * Returns: 0 on success, < 0 on failure
+ */
+static int asix_soft_reset(struct phy_device *phydev)
+{
+	int ret;
+
+	/* Asix PHY won't reset unless reset bit toggles */
+	ret = phy_write(phydev, MII_BMCR, 0);
+	if (ret < 0)
+		return ret;
+
+	return genphy_soft_reset(phydev);
+}
+
+/* AX88772A is not working properly with some old switches (NETGEAR EN 108TP):
+ * after autoneg is done and the link status is reported as active, the MII_LPA
+ * register is 0. This issue is not reproducible on AX88772C.
+ */
+static int asix_ax88772a_read_status(struct phy_device *phydev)
+{
+	int ret, val;
+
+	ret = genphy_update_link(phydev);
+	if (ret)
+		return ret;
+
+	if (!phydev->link)
+		return 0;
+
+	/* If MII_LPA is 0, phy_resolve_aneg_linkmode() will fail to resolve
+	 * linkmode so use MII_BMCR as default values.
+	 */
+	val = phy_read(phydev, MII_BMCR);
+	if (val < 0)
+		return val;
+
+	if (val & BMCR_SPEED100)
+		phydev->speed = SPEED_100;
+	else
+		phydev->speed = SPEED_10;
+
+	if (val & BMCR_FULLDPLX)
+		phydev->duplex = DUPLEX_FULL;
+	else
+		phydev->duplex = DUPLEX_HALF;
+
+	ret = genphy_read_lpa(phydev);
+	if (ret < 0)
+		return ret;
+
+	if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete)
+		phy_resolve_aneg_linkmode(phydev);
+
+	return 0;
+}
+
+static void asix_ax88772a_link_change_notify(struct phy_device *phydev)
+{
+	/* Reset PHY, otherwise MII_LPA will provide outdated information.
+	 * This issue is reproducible only with some link partner PHYs
+	 */
+	if (phydev->state == PHY_NOLINK) {
+		phy_init_hw(phydev);
+		phy_start_aneg(phydev);
+	}
+}
+
+static struct phy_driver asix_driver[] = {
+{
+	PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772A),
+	.name		= "Asix Electronics AX88772A",
+	.flags		= PHY_IS_INTERNAL,
+	.read_status	= asix_ax88772a_read_status,
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+	.soft_reset	= asix_soft_reset,
+	.link_change_notify	= asix_ax88772a_link_change_notify,
+}, {
+	PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772C),
+	.name		= "Asix Electronics AX88772C",
+	.flags		= PHY_IS_INTERNAL,
+	.suspend	= genphy_suspend,
+	.resume		= genphy_resume,
+	.soft_reset	= asix_soft_reset,
+}, {
+	.phy_id		= PHY_ID_ASIX_AX88796B,
+	.name		= "Asix Electronics AX88796B",
+	.phy_id_mask	= 0xfffffff0,
+	/* PHY_BASIC_FEATURES */
+	.soft_reset	= asix_soft_reset,
+} };
+
+module_phy_driver(asix_driver);
+
+static struct mdio_device_id __maybe_unused asix_tbl[] = {
+	{ PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772A) },
+	{ PHY_ID_MATCH_EXACT(PHY_ID_ASIX_AX88772C) },
+	{ PHY_ID_ASIX_AX88796B, 0xfffffff0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(mdio, asix_tbl);