linux-kernel - [PATCH net v2 2/2] net: fec: Suspend and resume the PHY

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Date: Thu, 29 Feb 2024 10:53:15 +0000
From: John Ernberg <john.ernberg@...ia.se>
To: Wei Fang <wei.fang@....com>
CC: Shenwei Wang <shenwei.wang@....com>, Clark Wang <xiaoning.wang@....com>,
	NXP Linux Team <linux-imx@....com>, "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, "Paolo
 Abeni" <pabeni@...hat.com>, Heiner Kallweit <hkallweit1@...il.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, John Ernberg
	<john.ernberg@...ia.se>
Subject: [PATCH net v2 2/2] net: fec: Suspend and resume the PHY

PHYs that are always-on will not enter their low power modes otherwise as
they have no regulator to be powered off with.

Since the PHY is picked up via {of_,}phy_connect() and dropped with
phy_disconnect() when the link is brought up and down respectively the only
cases were pm is needed is when the netif is running or or when the link
has never been up.

To deal with the latter case the PHY is suspended on discovery in probe,
since it won't be needed until link up.

Fixes: 557d5dc83f68 ("net: fec: use mac-managed PHY PM")
Signed-off-by: John Ernberg <john.ernberg@...ia.se>
---

v2: New patch
---
 drivers/net/ethernet/freescale/fec_main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 8decb1b072c5..c5394a4d8491 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -2539,8 +2539,10 @@ static int fec_enet_mii_init(struct platform_device *pdev)
 	/* find all the PHY devices on the bus and set mac_managed_pm to true */
 	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
 		phydev = mdiobus_get_phy(fep->mii_bus, addr);
-		if (phydev)
+		if (phydev) {
 			phydev->mac_managed_pm = true;
+			phy_suspend(phydev);
+		}
 	}
 
 	mii_cnt++;
@@ -4631,6 +4633,7 @@ static int __maybe_unused fec_suspend(struct device *dev)
 		if (fep->wol_flag & FEC_WOL_FLAG_ENABLE)
 			fep->wol_flag |= FEC_WOL_FLAG_SLEEP_ON;
 		phy_stop(ndev->phydev);
+		phy_suspend(ndev->phydev);
 		napi_disable(&fep->napi);
 		netif_tx_lock_bh(ndev);
 		netif_device_detach(ndev);
@@ -4716,6 +4719,7 @@ static int __maybe_unused fec_resume(struct device *dev)
 		netif_tx_unlock_bh(ndev);
 		napi_enable(&fep->napi);
 		phy_init_hw(ndev->phydev);
+		phy_resume(ndev->phydev);
 		phy_start(ndev->phydev);
 	}
 	rtnl_unlock();
-- 
2.43.0