net: usb: lan78xx: Improve error handling in PHY initialization

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>
Reviewed-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index e4f1663b62047b26321ad1a96ae96624632352f5..19db18cf0504d5e1570080483811f6765b0e9936 100644 (file)
--- 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;
                }
        }