6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mark Mentovai mark@mentovai.com
[ Upstream commit 225990c487c1023e7b3aa89beb6a68011fbc0461 ]
The PHY built in to the Realtek RTL8366S switch controller was previously supported by genphy_driver. This PHY does not implement MMD operations. Since commit 9b01c885be36 ("net: phy: c22: migrate to genphy_c45_write_eee_adv()"), MMD register reads have been made during phy_probe to determine EEE support. For genphy_driver, these reads are transformed into 802.3 annex 22D clause 45-over-clause 22 mmd_phy_indirect operations that perform MII register writes to MII_MMD_CTRL and MII_MMD_DATA. This overwrites those two MII registers, which on this PHY are reserved and have another function, rendering the PHY unusable while so configured.
Proper support for this PHY is restored by providing a phy_driver that declares MMD operations as unsupported by using the helper functions provided for that purpose, while remaining otherwise identical to genphy_driver.
Fixes: 9b01c885be36 ("net: phy: c22: migrate to genphy_c45_write_eee_adv()") Reported-by: Russell Senior russell@personaltelco.net Closes: https://github.com/openwrt/openwrt/issues/15981 Link: https://github.com/openwrt/openwrt/issues/15739 Signed-off-by: Mark Mentovai mark@mentovai.com Reviewed-by: Maxime Chevallier maxime.chevallier@bootlin.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/phy/realtek.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c index 337899c69738e..2604d9663a5b2 100644 --- a/drivers/net/phy/realtek.c +++ b/drivers/net/phy/realtek.c @@ -1083,6 +1083,13 @@ static struct phy_driver realtek_drvs[] = { .handle_interrupt = genphy_handle_interrupt_no_ack, .suspend = genphy_suspend, .resume = genphy_resume, + }, { + PHY_ID_MATCH_EXACT(0x001cc960), + .name = "RTL8366S Gigabit Ethernet", + .suspend = genphy_suspend, + .resume = genphy_resume, + .read_mmd = genphy_read_mmd_unsupported, + .write_mmd = genphy_write_mmd_unsupported, }, };