[PATCH net-next v5 1/6] net: usb: lan78xx: Improve error handling in PHY initialization

Oleksij Rempel
2025-03-19T08:50:01Z

Ensure that return values from `lan78xx_write_reg()`,
`lan78xx_read_reg()`, and `phy_find_first()` are properly checked and
propagated. Use `ERR_PTR(ret)` for error reporting in
`lan7801_phy_init()` and replace `-EIO` with `-ENODEV` where appropriate
to provide more accurate error codes.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
changes v5:
- make sure lan7801_phy_init() caller is testing against IS_ERR
instead of NULL.
changes v4:
- split the patch and move part of it before PHYlink migration
---
drivers/net/usb/lan78xx.c | 47 ++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 137adf6d5b08..13b5da18850a 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2510,14 +2510,13 @@ static void lan78xx_remove_irq_domain(struct lan78xx_net *dev)

static struct phy_device *lan7801_phy_init(struct lan78xx_net *dev)
{
- u32 buf;
- int ret;
struct fixed_phy_status fphy_status = {
.link = 1,
.speed = SPEED_1000,
.duplex = DUPLEX_FULL,
};
struct phy_device *phydev;
+ int ret;

phydev = phy_find_first(dev->mdiobus);
if (!phydev) {
@@ -2525,30 +2524,40 @@ static struct phy_device *lan7801_phy_init(struct lan78xx_net *dev)
phydev = fixed_phy_register(PHY_POLL, &fphy_status, NULL);
if (IS_ERR(phydev)) {
netdev_err(dev->net, "No PHY/fixed_PHY found\n");
- return NULL;
+ return ERR_PTR(-ENODEV);
}
netdev_dbg(dev->net, "Registered FIXED PHY\n");
dev->interface = PHY_INTERFACE_MODE_RGMII;
ret = lan78xx_write_reg(dev, MAC_RGMII_ID,
MAC_RGMII_ID_TXC_DELAY_EN_);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
ret = lan78xx_write_reg(dev, RGMII_TX_BYP_DLL, 0x3D00);
- ret = lan78xx_read_reg(dev, HW_CFG, &buf);
- buf |= HW_CFG_CLK125_EN_;
- buf |= HW_CFG_REFCLK25_EN_;
- ret = lan78xx_write_reg(dev, HW_CFG, buf);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ ret = lan78xx_update_reg(dev, HW_CFG, HW_CFG_CLK125_EN_ |
+ HW_CFG_REFCLK25_EN_,
+ HW_CFG_CLK125_EN_ | HW_CFG_REFCLK25_EN_);
+ if (ret < 0)
+ return ERR_PTR(ret);
} else {
if (!phydev->drv) {
netdev_err(dev->net, "no PHY driver found\n");
- return NULL;
+ return ERR_PTR(-EINVAL);
}
dev->interface = PHY_INTERFACE_MODE_RGMII_ID;
/* The PHY driver is responsible to configure proper RGMII
* interface delays. Disable RGMII delays on MAC side.
*/
- lan78xx_write_reg(dev, MAC_RGMII_ID, 0);
+ ret = lan78xx_write_reg(dev, MAC_RGMII_ID, 0);
+ if (ret < 0)
+ return ERR_PTR(ret);

phydev->is_internal = false;
}
+
return phydev;
}

@@ -2562,9 +2571,10 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
switch (dev->chipid) {
case ID_REV_CHIP_ID_7801_:
phydev = lan7801_phy_init(dev);
- if (!phydev) {
- netdev_err(dev->net, "lan7801: PHY Init Failed");
- return -EIO;
+ if (IS_ERR(phydev)) {
+ netdev_err(dev->net, "lan7801: failed to init PHY: %pe\n",
+ phydev);
+ return PTR_ERR(phydev);
}
break;

@@ -2573,7 +2583,7 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
phydev = phy_find_first(dev->mdiobus);
if (!phydev) {
netdev_err(dev->net, "no PHY found\n");
- return -EIO;
+ return -ENODEV;
}
phydev->is_internal = true;
dev->interface = PHY_INTERFACE_MODE_GMII;
@@ -2581,7 +2591,7 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)

default:
netdev_err(dev->net, "Unknown CHIP ID found\n");
- return -EIO;
+ return -ENODEV;
}

/* if phyirq is not set, use polling mode in phylib */
@@ -2633,7 +2643,10 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
sizeof(u32));
if (len >= 0) {
/* Ensure the appropriate LEDs are enabled */
- lan78xx_read_reg(dev, HW_CFG, &reg);
+ ret = lan78xx_read_reg(dev, HW_CFG, &reg);
+ if (ret < 0)
+ return ret;
+
reg &= ~(HW_CFG_LED0_EN_ |
HW_CFG_LED1_EN_ |
HW_CFG_LED2_EN_ |
@@ -2642,7 +2655,9 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
(len > 1) * HW_CFG_LED1_EN_ |
(len > 2) * HW_CFG_LED2_EN_ |
(len > 3) * HW_CFG_LED3_EN_;
- lan78xx_write_reg(dev, HW_CFG, reg);
+ ret = lan78xx_write_reg(dev, HW_CFG, reg);
+ if (ret < 0)
+ return ret;
}
}

--
2.39.5