[PATCH net-next 3/3] net: phy: mediatek: add driver for built-in 2.5G ethernet PHY on MT7988

Andrew Lunn andrew at lunn.ch
Sun Jan 19 09:31:44 PST 2025


> +	np = of_find_compatible_node(NULL, NULL, "mediatek,2p5gphy-fw");
> +	if (!np)
> +		return -ENOENT;

The device tree binding need documenting.

> +	/* Write magic number to safely stall MCU */
> +	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x800e, 0x1100);
> +	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x800f, 0x00df);

0x1100 and 0x00df are magic numbers, bit 0x800e and 0x800f are
not. Please add #defines.


> +
> +	for (i = 0; i < MT7988_2P5GE_PMB_FW_SIZE - 1; i += 4)
> +		writel(*((uint32_t *)(fw->data + i)), pmb_addr + i);
> +	dev_info(dev, "Firmware date code: %x/%x/%x, version: %x.%x\n",
> +		 be16_to_cpu(*((__be16 *)(fw->data +
> +					  MT7988_2P5GE_PMB_FW_SIZE - 8))),
> +		 *(fw->data + MT7988_2P5GE_PMB_FW_SIZE - 6),
> +		 *(fw->data + MT7988_2P5GE_PMB_FW_SIZE - 5),
> +		 *(fw->data + MT7988_2P5GE_PMB_FW_SIZE - 2),
> +		 *(fw->data + MT7988_2P5GE_PMB_FW_SIZE - 1));
> +
> +	writew(reg & ~MD32_EN, mcu_csr_base + MD32_EN_CFG);
> +	writew(reg | MD32_EN, mcu_csr_base + MD32_EN_CFG);
> +	phy_set_bits(phydev, MII_BMCR, BMCR_RESET);
> +	/* We need a delay here to stabilize initialization of MCU */
> +	usleep_range(7000, 8000);
> +	dev_info(dev, "Firmware loading/trigger ok.\n");

We generally don't spam the log for "Happy Days" conditions. Please
only log if firmware download fails.

> +static int mt798x_2p5ge_phy_get_features(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	ret = genphy_c45_pma_read_abilities(phydev);
> +	if (ret)
> +		return ret;
> +
> +	/* This phy can't handle collision, and neither can (XFI)MAC it's
> +	 * connected to. Although it can do HDX handshake, it doesn't support
> +	 * CSMA/CD that HDX requires.
> +	 */
> +	linkmode_clear_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
> +			   phydev->supported);

So it can do 10BaseT_Half? What about 1000BaseT_Half?

As you said somewhere, 10/100/1G are not in the C45 space. So does
genphy_c45_pma_read_abilities() report these features?

	Andrew



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