The enabling/disabling of EEE in the MAC should happen as a result of
auto negotiation. So move the enable/disable into
lan783xx_phy_link_status_change() which gets called by phylib when
there is a change in link status.

lan78xx_set_eee() now just programs the hardware with the LPI
timer value, and passed everything else to phylib, so it can correctly
setup the PHY.

lan743x_get_eee() relies on phylib doing most of the work, the
MAC driver just adds the LPI timer value.

Call phy_support_eee() to indicate the MAC does actually support EEE.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/usb/lan78xx.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 80ee4fcdfb36..0030be502daa 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1692,15 +1692,10 @@ static int lan78xx_get_eee(struct net_device *net, struct ethtool_keee *edata)
 
 	ret = lan78xx_read_reg(dev, MAC_CR, &buf);
 	if (buf & MAC_CR_EEE_EN_) {
-		edata->eee_enabled = true;
-		edata->tx_lpi_enabled = true;
 		/* EEE_TX_LPI_REQ_DLY & tx_lpi_timer are same uSec unit */
 		ret = lan78xx_read_reg(dev, EEE_TX_LPI_REQ_DLY, &buf);
 		edata->tx_lpi_timer = buf;
 	} else {
-		edata->eee_enabled = false;
-		edata->eee_active = false;
-		edata->tx_lpi_enabled = false;
 		edata->tx_lpi_timer = 0;
 	}
 
@@ -1721,24 +1716,16 @@ static int lan78xx_set_eee(struct net_device *net, struct ethtool_keee *edata)
 	if (ret < 0)
 		return ret;
 
-	if (edata->eee_enabled) {
-		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
-		buf |= MAC_CR_EEE_EN_;
-		ret = lan78xx_write_reg(dev, MAC_CR, buf);
-
-		phy_ethtool_set_eee(net->phydev, edata);
-
-		buf = (u32)edata->tx_lpi_timer;
-		ret = lan78xx_write_reg(dev, EEE_TX_LPI_REQ_DLY, buf);
-	} else {
-		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
-		buf &= ~MAC_CR_EEE_EN_;
-		ret = lan78xx_write_reg(dev, MAC_CR, buf);
-	}
+	ret = phy_ethtool_set_eee(net->phydev, edata);
+	if (ret < 0)
+		goto out;
 
+	buf = (u32)edata->tx_lpi_timer;
+	ret = lan78xx_write_reg(dev, EEE_TX_LPI_REQ_DLY, buf);
+out:
 	usb_autopm_put_interface(dev->intf);
 
-	return 0;
+	return ret;
 }
 
 static u32 lan78xx_get_link(struct net_device *net)
@@ -2114,7 +2101,20 @@ static void lan78xx_remove_mdio(struct lan78xx_net *dev)
 
 static void lan78xx_link_status_change(struct net_device *net)
 {
+	struct lan78xx_net *dev = netdev_priv(net);
 	struct phy_device *phydev = net->phydev;
+	u32 data;
+	int ret;
+
+	ret = lan78xx_read_reg(dev, MAC_CR, &data);
+	if (ret < 0)
+		return;
+
+	if (phydev->enable_tx_lpi)
+		data |=  MAC_CR_EEE_EN_;
+	else
+		data &= ~MAC_CR_EEE_EN_;
+	lan78xx_write_reg(dev, MAC_CR, data);
 
 	phy_print_status(phydev);
 }
@@ -2408,6 +2408,8 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
 	mii_adv_to_linkmode_adv_t(fc, mii_adv);
 	linkmode_or(phydev->advertising, fc, phydev->advertising);
 
+	phy_support_eee(phydev);
+
 	if (phydev->mdio.dev.of_node) {
 		u32 reg;
 		int len;

-- 
2.43.0

Hi Andrew,

On Sat, Apr 06, 2024 at 03:15:59PM -0500, Andrew Lunn wrote:
.....
> ---
> -	if (edata->eee_enabled) {
> -		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
> -		buf |= MAC_CR_EEE_EN_;
> -		ret = lan78xx_write_reg(dev, MAC_CR, buf);
> -
> -		phy_ethtool_set_eee(net->phydev, edata);
> -
> -		buf = (u32)edata->tx_lpi_timer;
> -		ret = lan78xx_write_reg(dev, EEE_TX_LPI_REQ_DLY, buf);
> -	} else {
> -		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
> -		buf &= ~MAC_CR_EEE_EN_;
> -		ret = lan78xx_write_reg(dev, MAC_CR, buf);
> -	}
> +	ret = phy_ethtool_set_eee(net->phydev, edata);
> +	if (ret < 0)
> +		goto out;
>  
> +	buf = (u32)edata->tx_lpi_timer;
> +	ret = lan78xx_write_reg(dev, EEE_TX_LPI_REQ_DLY, buf);

According to the documentation:
"Host software should only change this field when Energy Efficient
Ethernet Enable (EEEEN) is cleared."

Even more: "A value of zero may adversely affect the ability of the TX
data path to support Gigabit operation. A reasonable value when the part
is operating at Gigabit speeds is 50 us."

Previous code seems to not care about it too. So, it would be not a
regression if something is broken.

Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>

I'll get some time to work on this driver in some months, in this case
I'll take a closer look on EEE too.

Regards,
Oleksij
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