[PATCH net-next v2] net: phy: bcm84881: add BCM84891/BCM84892 support
From: Daniel Wagner <hidden>
Date: 2026-03-24 19:06:42
Subsystem:
broadcom ethernet phy drivers, ethernet phy library, networking drivers, the rest · Maintainers:
Florian Fainelli, Andrew Lunn, Heiner Kallweit, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The BCM84891 and BCM84892 are 10GBASE-T PHYs in the same family as the BCM84881, sharing the register map and most callbacks. They add USXGMII as a host interface mode. bcm8489x_config_init() is separate from bcm84881_config_init(): it allows only USXGMII (the only host mode available on the tested hardware) and clears MDIO_CTRL1_LPOWER, which is set at boot on the tested platform. Does not recur on ifdown/ifup, cable events, or link-partner advertisement changes, so config_init is sufficient. For USXGMII, read_status() skips the 0x4011 host-mode register: it returns the same value regardless of negotiated copper speed (USXGMII symbol replication). Speed comes from phy_resolve_aneg_linkmode() via standard C45 AN resolution. Tested on TRENDnet TEG-S750 (RTL9303 + 1x BCM84891 + 4x BCM84892) running OpenWrt, where the MDIO controller driver is currently OpenWrt-specific. Link verified at 100M, 1G, 2.5G, 10G. Signed-off-by: Daniel Wagner <redacted> --- Changes in v2: - Separate bcm8489x_config_init() that allows only USXGMII. v1 also allowed USXGMII for BCM84881 (which doesn't support it), and put SGMII/2500BASEX/10GBASER in the 8489x possible_interfaces which I can't substantiate on this hardware. (Russell) - LPOWER clear moved from config_aneg to config_init. Characterized on hardware: boot-time only, does not recur on ifdown/ifup, cable events, or link-partner advertisement changes. (Russell) - Dropped LED support; will figure out the PHY LED framework approach for bicolor speed-mapped LEDs as a follow-up. (Russell, Andrew) - PHY_ID_MATCH_MODEL(). (Russell, Andrew) - is_bcm8489x() helper removed; the interface mode now suffices as a discriminator in read_status since only the 8489x config_init allows USXGMII. v1: https://lore.kernel.org/netdev/20260324152503.1522071-2-wagner.daniel.t@gmail.com/ (local) drivers/net/phy/bcm84881.c | 48 +++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-)
diff --git a/drivers/net/phy/bcm84881.c b/drivers/net/phy/bcm84881.c
index d7f7cc44c5..f114212dd3 100644
--- a/drivers/net/phy/bcm84881.c
+++ b/drivers/net/phy/bcm84881.c@@ -54,6 +54,21 @@ static int bcm84881_config_init(struct phy_device *phydev) return 0; } +static int bcm8489x_config_init(struct phy_device *phydev) +{ + __set_bit(PHY_INTERFACE_MODE_USXGMII, phydev->possible_interfaces); + + if (phydev->interface != PHY_INTERFACE_MODE_USXGMII) + return -ENODEV; + + /* MDIO_CTRL1_LPOWER is set at boot on the tested platform. Does not + * recur on ifdown/ifup, cable events, or link-partner advertisement + * changes; clear it once. + */ + return phy_clear_bits_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_CTRL1, + MDIO_CTRL1_LPOWER); +} + static int bcm84881_probe(struct phy_device *phydev) { /* This driver requires PMAPMD and AN blocks */
@@ -201,6 +216,15 @@ static int bcm84881_read_status(struct phy_device *phydev) return 0; } + /* BCM84891/92 on USXGMII: the host interface mode doesn't change + * with copper speed (USXGMII symbol replication; the MAC receives + * the negotiated copper speed, not 10G, so no rate adaptation). + * Skip 0x4011; phy_resolve_aneg_linkmode() above already set the + * speed. Only bcm8489x_config_init() allows USXGMII. + */ + if (phydev->interface == PHY_INTERFACE_MODE_USXGMII) + return genphy_c45_read_mdix(phydev); + /* Set the host link mode - we set the phy interface mode and * the speed according to this register so that downshift works. * We leave the duplex setting as per the resolution from the
@@ -256,6 +280,26 @@ static struct phy_driver bcm84881_drivers[] = { .config_aneg = bcm84881_config_aneg, .aneg_done = bcm84881_aneg_done, .read_status = bcm84881_read_status, + }, { + PHY_ID_MATCH_MODEL(0x35905080), + .name = "Broadcom BCM84891", + .inband_caps = bcm84881_inband_caps, + .config_init = bcm8489x_config_init, + .probe = bcm84881_probe, + .get_features = bcm84881_get_features, + .config_aneg = bcm84881_config_aneg, + .aneg_done = bcm84881_aneg_done, + .read_status = bcm84881_read_status, + }, { + PHY_ID_MATCH_MODEL(0x359050a0), + .name = "Broadcom BCM84892", + .inband_caps = bcm84881_inband_caps, + .config_init = bcm8489x_config_init, + .probe = bcm84881_probe, + .get_features = bcm84881_get_features, + .config_aneg = bcm84881_config_aneg, + .aneg_done = bcm84881_aneg_done, + .read_status = bcm84881_read_status, }, };
@@ -264,9 +308,11 @@ module_phy_driver(bcm84881_drivers); /* FIXME: module auto-loading for Clause 45 PHYs seems non-functional */ static const struct mdio_device_id __maybe_unused bcm84881_tbl[] = { { 0xae025150, 0xfffffff0 }, + { PHY_ID_MATCH_MODEL(0x35905080) }, + { PHY_ID_MATCH_MODEL(0x359050a0) }, { }, }; MODULE_AUTHOR("Russell King"); -MODULE_DESCRIPTION("Broadcom BCM84881 PHY driver"); +MODULE_DESCRIPTION("Broadcom BCM84881/BCM84891/BCM84892 PHY driver"); MODULE_DEVICE_TABLE(mdio, bcm84881_tbl); MODULE_LICENSE("GPL");
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2.47.3