Subject: Re: [PATCH net-next v12 3/3] net: stmmac: dwmac-nuvoton: Add dwmac glue for Nuvoton MA35 family

From: "Russell King (Oracle)" <[email-masked]>
Date: Tue, 10 Feb 2026 13:12:12 +0000

Please note that net-next is currently closed, so you should be sending
net-next patches with "RFC". See section 1.4 of:
https://docs.kernel.org/process/maintainer-netdev.html

On Tue, Feb 10, 2026 at 01:22:26PM +0800, Joey Lu wrote:
> +static int nvt_gmac_setup(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	phy_interface_t phy_mode;
> +	struct regmap *regmap;
> +	u32 macid, miscr, reg;
> +	int ret;
> +
> +	regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node, "nuvoton,sys", 1, &macid);
> +	if (IS_ERR(regmap))
> +		ret = dev_err_probe(dev, PTR_ERR(regmap), "Failed to get sys register\n");
> +
> +	if (macid > 1)
> +		ret = dev_err_probe(dev, -EINVAL, "Invalid sys arguments\n");
> +
> +	if (of_get_phy_mode(pdev->dev.of_node, &phy_mode))
> +		ret = dev_err_probe(dev, -EINVAL, "Missing phy mode property\n");

If you pass in the plat_dat to this function, then you have access to
plat_dat->phy_interface. I went through all the dwmac glue code and
removed such PHY interface gets, so please don't introduce new
instances.

> +
> +	miscr = (macid == 0) ? NVT_REG_SYS_GMAC0MISCR : NVT_REG_SYS_GMAC1MISCR;

I find the use of "miscr" to be the register offset, and "reg" to be
the register value is confusing. Normally they're the other way around.

> +
> +	switch (phy_mode) {
> +	case PHY_INTERFACE_MODE_RGMII:
> +	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
> +		ret = nvt_gmac_get_delay(dev, "rx-internal-delay-ps");
> +		if (ret < 0)
> +			return ret;
> +		reg = FIELD_PREP(NVT_RX_DELAY_MASK, ret);
> +
> +		ret = nvt_gmac_get_delay(dev, "tx-internal-delay-ps");
> +		if (ret < 0)
> +			return ret;
> +		reg |= FIELD_PREP(NVT_TX_DELAY_MASK, ret);
> +		break;
> +	case PHY_INTERFACE_MODE_RMII:
> +		reg = NVT_MISCR_RMII;
> +			break;
> +	default:
> +		return dev_err_probe(dev, -EINVAL, "Unsupported phy-mode (%d)\n", phy_mode);
> +	}
> +
> +	regmap_update_bits(regmap, miscr,
> +			   NVT_RX_DELAY_MASK | NVT_TX_DELAY_MASK | NVT_MISCR_RMII, reg);

Please consider programming the NVT_MISCR_RMII bit via the
plat_dat->set_phy_intf_sel() method.

Is this register preserved over suspend/resume ?

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!