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net: usb: lan78xx: refactor PHY init to separate detection and MAC configuration

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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 <o.rempel@pengutronix.de>
Reviewed-by: Thangaraj Samynathan <thangaraj.s@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Oleksij Rempel 2025-05-05 10:43:37 +02:00 committed by David S. Miller
parent 3da0ae5270
commit d39f339d26
1 changed files with 130 additions and 48 deletions
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178
drivers/net/usb/lan78xx.c
View File

@ -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;
/* Attempt to locate a PHY on the MDIO bus */
phydev = phy_find_first(dev->mdiobus);
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;
}
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;
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);
}
netdev_dbg(dev->net, "Registered FIXED PHY\n");
dev->interface = PHY_INTERFACE_MODE_RGMII;
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;
phydev = lan78xx_get_phy(dev);
if (IS_ERR(phydev))
return PTR_ERR(phydev);
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;
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)