kernel/linux.git/drivers/net/phy/microchip.c, branch v6.6.132

net: phy: microchip: limit 100M workaround to link-down events on LAN88xx

2025-07-17T16:35:19+00:00

[ Upstream commit dd4360c0e8504f2f7639c7f5d07c93cfd6a98333 ] Restrict the 100Mbit forced-mode workaround to link-down transitions only, to prevent repeated link reset cycles in certain configurations. The workaround was originally introduced to improve signal reliability when switching cables between long and short distances. It temporarily forces the PHY into 10 Mbps before returning to 100 Mbps. However, when used with autonegotiating link partners (e.g., Intel i350), executing this workaround on every link change can confuse the partner and cause constant renegotiation loops. This results in repeated link down/up transitions and the PHY never reaching a stable state. Limit the workaround to only run during the PHY_NOLINK state. This ensures it is triggered only once per link drop, avoiding disruptive toggling while still preserving its intended effect. Note: I am not able to reproduce the original issue that this workaround addresses. I can only confirm that 100 Mbit mode works correctly in my test setup. Based on code inspection, I assume the workaround aims to reset some internal state machine or signal block by toggling speeds. However, a PHY reset is already performed earlier in the function via phy_init_hw(), which may achieve a similar effect. Without a reproducer, I conservatively keep the workaround but restrict its conditions. Fixes: e57cf3639c32 ("net: lan78xx: fix accessing the LAN7800's internal phy specific registers from the MAC driver") Signed-off-by: Oleksij Rempel Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/20250709130753.3994461-3-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: phy: microchip: force IRQ polling mode for lan88xx

2025-05-02T05:50:46+00:00

commit 30a41ed32d3088cd0d682a13d7f30b23baed7e93 upstream. With lan88xx based devices the lan78xx driver can get stuck in an interrupt loop while bringing the device up, flooding the kernel log with messages like the following: lan78xx 2-3:1.0 enp1s0u3: kevent 4 may have been dropped Removing interrupt support from the lan88xx PHY driver forces the driver to use polling instead, which avoids the problem. The issue has been observed with Raspberry Pi devices at least since 4.14 (see [1], bug report for their downstream kernel), as well as with Nvidia devices [2] in 2020, where disabling interrupts was the vendor-suggested workaround (together with the claim that phylib changes in 4.9 made the interrupt handling in lan78xx incompatible). Iperf reports well over 900Mbits/sec per direction with client in --dualtest mode, so there does not seem to be a significant impact on throughput (lan88xx device connected via switch to the peer). [1] https://github.com/raspberrypi/linux/issues/2447 [2] https://forums.developer.nvidia.com/t/jetson-xavier-and-lan7800-problem/142134/11 Link: https://lore.kernel.org/0901d90d-3f20-4a10-b680-9c978e04ddda@lunn.ch Fixes: 792aec47d59d ("add microchip LAN88xx phy driver") Signed-off-by: Fiona Klute Cc: kernel-list@raspberrypi.com Cc: stable@vger.kernel.org Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/20250416102413.30654-1-fiona.klute@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman

net: lan78xx: fix accessing the LAN7800's internal phy specific registers from the MAC driver

2023-03-03T06:21:07+00:00

Move the LAN7800 internal phy (phy ID 0x0007c132) specific register accesses to the phy driver (microchip.c). Fix the error reported by Enguerrand de Ribaucourt in December 2022, "Some operations during the cable switch workaround modify the register LAN88XX_INT_MASK of the PHY. However, this register is specific to the LAN8835 PHY. For instance, if a DP8322I PHY is connected to the LAN7801, that register (0x19), corresponds to the LED and MAC address configuration, resulting in unapropriate behavior." I did not test with the DP8322I PHY, but I tested with an EVB-LAN7800 with the internal PHY. Fixes: 14437e3fa284 ("lan78xx: workaround of forced 100 Full/Half duplex mode error") Signed-off-by: Yuiko Oshino Reviewed-by: Andrew Lunn Link: https://lore.kernel.org/r/20230301154307.30438-1-yuiko.oshino@microchip.com Signed-off-by: Jakub Kicinski

net: phy: microchip: add comments for the modified LAN88xx phy ID mask.

2022-05-11T01:57:14+00:00

add comments for the updated LAN88xx phy ID mask in the previous patch. Signed-off-by: Yuiko Oshino Signed-off-by: Jakub Kicinski

net: phy: microchip: update LAN88xx phy ID and phy ID mask.

2022-05-09T11:20:56+00:00

update LAN88xx phy ID and phy ID mask because the existing code conflicts with the LAN8742 phy. The current phy IDs on the available hardware. LAN8742 0x0007C130, 0x0007C131 LAN88xx 0x0007C132 Signed-off-by: Yuiko Oshino Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller

net: phy: microchip: remove the use of .ack_interrupt()

2020-11-17T19:36:59+00:00

In preparation of removing the .ack_interrupt() callback, we must replace its occurrences (aka phy_clear_interrupt), from the 2 places where it is called from (phy_enable_interrupts and phy_disable_interrupts), with equivalent functionality. This means that clearing interrupts now becomes something that the PHY driver is responsible of doing, before enabling interrupts and after clearing them. Make this driver follow the new contract. Cc: Nisar Sayed Cc: Yuiko Oshino Signed-off-by: Ioana Ciornei Signed-off-by: Jakub Kicinski

net: phy: microchip: implement generic .handle_interrupt() callback

2020-11-17T19:36:59+00:00

In an attempt to actually support shared IRQs in phylib, we now move the responsibility of triggering the phylib state machine or just returning IRQ_NONE, based on the IRQ status register, to the PHY driver. Having 3 different IRQ handling callbacks (.handle_interrupt(), .did_interrupt() and .ack_interrupt() ) is confusing so let the PHY driver implement directly an IRQ handler like any other device driver. Make this driver follow the new convention. Cc: Nisar Sayed Cc: Yuiko Oshino Signed-off-by: Ioana Ciornei Signed-off-by: Jakub Kicinski

net: phy: remove calls to genphy_config_init

2019-08-17T19:34:50+00:00

Supported PHY features are either auto-detected or explicitly set. In both cases calling genphy_config_init isn't needed. All that genphy_config_init does is removing features that are set as supported but can't be auto-detected. Basically it duplicates the code in genphy_read_abilities. Therefore remove such calls from all PHY drivers. v2: - remove call also from new adin PHY driver v3: - pass NULL as config_init function pointer for dp83848 Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller

net: phy: switch drivers to use dynamic feature detection

2019-04-16T00:19:54+00:00

Recently genphy_read_abilities() has been added that dynamically detects clause 22 PHY abilities. I *think* this detection should work with all supported PHY's, at least for the ones with basic features sets, i.e. PHY_BASIC_FEATURES and PHY_GBIT_FEATURES. So let's remove setting these features explicitly and rely on phylib feature detection. I don't have access to most of these PHY's, therefore I'd appreciate regression testing. v2: - make the feature constant a comment so that readers know which features are supported by the respective PHY Signed-off-by: Heiner Kallweit Tested-by: Andrew Lunn Signed-off-by: David S. Miller

net: phy: Convert some PHY and MDIO driver files to SPDX headers

2019-01-23T04:53:08+00:00

Where the license text and the MODULE_LICENSE() value agree, convert to using an SPDX header, removing the license text. Signed-off-by: Andrew Lunn Signed-off-by: David S. Miller