netdev - [PATCH net v4 2/5] net: phy: micrel: disable suspend/resume callbacks following errata

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Date: Fri, 31 May 2024 14:24:27 +0000
From: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@...oirfairelinux.com>
To: netdev@...r.kernel.org
Cc: andrew@...n.ch,
	hkallweit1@...il.com,
	linux@...linux.org.uk,
	woojung.huh@...rochip.com,
	UNGLinuxDriver@...rochip.com,
	Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@...oirfairelinux.com>
Subject: [PATCH net v4 2/5] net: phy: micrel: disable suspend/resume callbacks following errata

Microchip's erratas state that powering down a PHY may cause errors
on the adjacent PHYs due to the power supply noise. The suggested
workaround is to avoid toggling the powerdown bit dynamically while
traffic may be present.

Fixes: fc3973a1fa09 ("phy: micrel: add Microchip KSZ 9477 Switch PHY support")
Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@...oirfairelinux.com>
---
v4:
 - rebase on net/main
 - add Fixes tag
v3: https://lore.kernel.org/all/20240530102436.226189-3-enguerrand.de-ribaucourt@savoirfairelinux.com/
---
 drivers/net/phy/micrel.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 8a6dfaceeab3..2608d6cc7257 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -5492,8 +5492,9 @@ static struct phy_driver ksphy_driver[] = {
 	.config_init	= ksz9477_config_init,
 	.config_intr	= kszphy_config_intr,
 	.handle_interrupt = kszphy_handle_interrupt,
-	.suspend	= genphy_suspend,
-	.resume		= genphy_resume,
+	/* No suspend/resume callbacks because of errata DS80000758:
+	 * Toggling PHY Powerdown can cause errors or link failures in adjacent PHYs
+	 */
 	.get_features	= ksz9477_get_features,
 }, {
 	.phy_id		= PHY_ID_KSZ9897,
-- 
2.34.1