From d39f339d2603736ff90b0b32d9aea3b954307fd5 Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Mon, 5 May 2025 10:43:37 +0200 Subject: [PATCH] net: usb: lan78xx: refactor PHY init to separate detection and MAC configuration Split out PHY detection into lan78xx_get_phy() and MAC-side setup into lan78xx_mac_prepare_for_phy(), making the main lan78xx_phy_init() cleaner and easier to follow. This improves separation of concerns and prepares the code for a future transition to phylink. Fixed PHY registration and interface selection are now handled in lan78xx_get_phy(), while MAC-side delay configuration is done in lan78xx_mac_prepare_for_phy(). The fixed PHY fallback is preserved for setups like EVB-KSZ9897-1, where LAN7801 connects directly to a KSZ switch without a standard PHY or device tree support. No functional changes intended. Signed-off-by: Oleksij Rempel Reviewed-by: Thangaraj Samynathan Signed-off-by: David S. Miller --- drivers/net/usb/lan78xx.c | 174 ++++++++++++++++++++++++++++---------- 1 file changed, 128 insertions(+), 46 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index 9c0658227bde..7f1ecc415d53 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2508,53 +2508,145 @@ static void lan78xx_remove_irq_domain(struct lan78xx_net *dev) dev->domain_data.irqdomain = NULL; } -static struct phy_device *lan7801_phy_init(struct lan78xx_net *dev) +/** + * lan78xx_register_fixed_phy() - Register a fallback fixed PHY + * @dev: LAN78xx device + * + * Registers a fixed PHY with 1 Gbps full duplex. This is used in special cases + * like EVB-KSZ9897-1, where LAN7801 acts as a USB-to-Ethernet interface to a + * switch without a visible PHY. + * + * Return: pointer to the registered fixed PHY, or ERR_PTR() on error. + */ +static struct phy_device *lan78xx_register_fixed_phy(struct lan78xx_net *dev) { struct fixed_phy_status fphy_status = { .link = 1, .speed = SPEED_1000, .duplex = DUPLEX_FULL, }; + + netdev_info(dev->net, + "No PHY found on LAN7801 – registering fixed PHY (e.g. EVB-KSZ9897-1)\n"); + + return fixed_phy_register(PHY_POLL, &fphy_status, NULL); +} + +/** + * lan78xx_get_phy() - Probe or register PHY device and set interface mode + * @dev: LAN78xx device structure + * + * This function attempts to find a PHY on the MDIO bus. If no PHY is found + * and the chip is LAN7801, it registers a fixed PHY as fallback. It also + * sets dev->interface based on chip ID and detected PHY type. + * + * Return: a valid PHY device pointer, or ERR_PTR() on failure. + */ +static struct phy_device *lan78xx_get_phy(struct lan78xx_net *dev) +{ struct phy_device *phydev; - int ret; + /* Attempt to locate a PHY on the MDIO bus */ phydev = phy_find_first(dev->mdiobus); - if (!phydev) { - netdev_dbg(dev->net, "PHY Not Found!! Registering Fixed PHY\n"); - phydev = fixed_phy_register(PHY_POLL, &fphy_status, NULL); - if (IS_ERR(phydev)) { - netdev_err(dev->net, "No PHY/fixed_PHY found\n"); - return ERR_PTR(-ENODEV); + + switch (dev->chipid) { + case ID_REV_CHIP_ID_7801_: + if (phydev) { + /* External RGMII PHY detected */ + dev->interface = PHY_INTERFACE_MODE_RGMII_ID; + phydev->is_internal = false; + + if (!phydev->drv) + netdev_warn(dev->net, + "PHY driver not found – assuming RGMII delays are on PCB or strapped for the PHY\n"); + + return phydev; } - netdev_dbg(dev->net, "Registered FIXED PHY\n"); + dev->interface = PHY_INTERFACE_MODE_RGMII; + /* No PHY found – fallback to fixed PHY (e.g. KSZ switch board) */ + return lan78xx_register_fixed_phy(dev); + + case ID_REV_CHIP_ID_7800_: + case ID_REV_CHIP_ID_7850_: + if (!phydev) + return ERR_PTR(-ENODEV); + + /* These use internal GMII-connected PHY */ + dev->interface = PHY_INTERFACE_MODE_GMII; + phydev->is_internal = true; + return phydev; + + default: + netdev_err(dev->net, "Unknown CHIP ID: 0x%08x\n", dev->chipid); + return ERR_PTR(-ENODEV); + } +} + +/** + * lan78xx_mac_prepare_for_phy() - Preconfigure MAC-side interface settings + * @dev: LAN78xx device + * + * Configure MAC-side registers according to dev->interface, which should be + * set by lan78xx_get_phy(). + * + * - For PHY_INTERFACE_MODE_RGMII: + * Enable MAC-side TXC delay. This mode seems to be used in a special setup + * without a real PHY, likely on EVB-KSZ9897-1. In that design, LAN7801 is + * connected to the KSZ9897 switch, and the link timing is expected to be + * hardwired (e.g. via strapping or board layout). No devicetree support is + * assumed here. + * + * - For PHY_INTERFACE_MODE_RGMII_ID: + * Disable MAC-side delay and rely on the PHY driver to provide delay. + * + * - For GMII, no MAC-specific config is needed. + * + * Return: 0 on success or a negative error code. + */ +static int lan78xx_mac_prepare_for_phy(struct lan78xx_net *dev) +{ + int ret; + + switch (dev->interface) { + case PHY_INTERFACE_MODE_RGMII: + /* Enable MAC-side TX clock delay */ ret = lan78xx_write_reg(dev, MAC_RGMII_ID, MAC_RGMII_ID_TXC_DELAY_EN_); if (ret < 0) - return ERR_PTR(ret); + return ret; ret = lan78xx_write_reg(dev, RGMII_TX_BYP_DLL, 0x3D00); if (ret < 0) - return ERR_PTR(ret); + return ret; - ret = lan78xx_update_reg(dev, HW_CFG, HW_CFG_CLK125_EN_ | - HW_CFG_REFCLK25_EN_, + 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 { - dev->interface = PHY_INTERFACE_MODE_RGMII_ID; - /* The PHY driver is responsible to configure proper RGMII - * interface delays. Disable RGMII delays on MAC side. - */ + return ret; + + break; + + case PHY_INTERFACE_MODE_RGMII_ID: + /* Disable MAC-side TXC delay, PHY provides it */ ret = lan78xx_write_reg(dev, MAC_RGMII_ID, 0); if (ret < 0) - return ERR_PTR(ret); + return ret; - phydev->is_internal = false; + break; + + case PHY_INTERFACE_MODE_GMII: + /* No MAC-specific configuration required */ + break; + + default: + netdev_warn(dev->net, "Unsupported interface mode: %d\n", + dev->interface); + break; } - return phydev; + return 0; } static int lan78xx_phy_init(struct lan78xx_net *dev) @@ -2564,31 +2656,13 @@ static int lan78xx_phy_init(struct lan78xx_net *dev) u32 mii_adv; struct phy_device *phydev; - switch (dev->chipid) { - case ID_REV_CHIP_ID_7801_: - phydev = lan7801_phy_init(dev); - if (IS_ERR(phydev)) { - netdev_err(dev->net, "lan7801: failed to init PHY: %pe\n", - phydev); - return PTR_ERR(phydev); - } - break; - - case ID_REV_CHIP_ID_7800_: - case ID_REV_CHIP_ID_7850_: - phydev = phy_find_first(dev->mdiobus); - if (!phydev) { - netdev_err(dev->net, "no PHY found\n"); - return -ENODEV; - } - phydev->is_internal = true; - dev->interface = PHY_INTERFACE_MODE_GMII; - break; + phydev = lan78xx_get_phy(dev); + if (IS_ERR(phydev)) + return PTR_ERR(phydev); - default: - netdev_err(dev->net, "Unknown CHIP ID found\n"); - return -ENODEV; - } + ret = lan78xx_mac_prepare_for_phy(dev); + if (ret < 0) + goto free_phy; /* if phyirq is not set, use polling mode in phylib */ if (dev->domain_data.phyirq > 0) @@ -2662,6 +2736,14 @@ static int lan78xx_phy_init(struct lan78xx_net *dev) dev->fc_autoneg = phydev->autoneg; return 0; + +free_phy: + if (phy_is_pseudo_fixed_link(phydev)) { + fixed_phy_unregister(phydev); + phy_device_free(phydev); + } + + return ret; } static int lan78xx_set_rx_max_frame_length(struct lan78xx_net *dev, int size) -- 2.50.1