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

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Message-ID: <aYsurPBMnzWDZCco@shell.armlinux.org.uk>
Date: Tue, 10 Feb 2026 13:12:12 +0000
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Joey Lu <a0987203069@...il.com>
Cc: andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com, robh@...nel.org,
	krzk+dt@...nel.org, conor+dt@...nel.org, mcoquelin.stm32@...il.com,
	richardcochran@...il.com, alexandre.torgue@...s.st.com,
	joabreu@...opsys.com, ychuang3@...oton.com, schung@...oton.com,
	yclu4@...oton.com, peppe.cavallaro@...com,
	linux-arm-kernel@...ts.infradead.org, netdev@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	openbmc@...ts.ozlabs.org, linux-stm32@...md-mailman.stormreply.com,
	Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH net-next v12 3/3] net: stmmac: dwmac-nuvoton: Add dwmac
 glue for Nuvoton MA35 family

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/
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