Re: [RFC PATCH 03/11] phy: ti: introduce phy-gmii-sel driver

On Mon, Oct 08, 2018 at 06:49:41PM -0500, Grygorii Strashko wrote:

+static int phy_gmii_sel_mode(struct phy *phy, phy_interface_t intf_mode)
+{
+	struct phy_gmii_sel_phy_priv *if_phy = phy_get_drvdata(phy);
+	const struct phy_gmii_sel_soc_data *soc_data = if_phy->priv->soc_data;
+	struct device *dev = if_phy->priv->dev;
+	struct regmap_field *regfield;
+	int ret, rgmii_id = 0;
+	u32 mode = 0;
+
+	if_phy->phy_if_mode = intf_mode;
+
+	switch (if_phy->phy_if_mode) {
+	case PHY_INTERFACE_MODE_RMII:
+		mode = AM33XX_GMII_SEL_MODE_RMII;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+		mode = AM33XX_GMII_SEL_MODE_RGMII;
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		mode = AM33XX_GMII_SEL_MODE_RGMII;
+		rgmii_id = 1;
+		break;

Hi Grygorii

It looks like the MAC can do AM33XX_GMII_SEL_MODE_RGMII and
AM33XX_GMII_SEL_MODE_RGMII_ID. I don't think it can do
AM33XX_GMII_SEL_MODE_RGMII_RXID or AM33XX_GMII_SEL_MODE_RGMII_TXID?  I
would prefer it return -EINVAL when asked to do something it cannot
do.

+
+	default:
+		dev_warn(dev,
+			 "port%u: unsupported mode: \"%s\". Defaulting to MII.\n",
+			 if_phy->id, phy_modes(rgmii_id));
+		/* fall through */

Returning -EINVAL would be better. Otherwise the DT might never get
fixed.

+	case PHY_INTERFACE_MODE_MII:
+		mode = AM33XX_GMII_SEL_MODE_MII;
+		break;
+	};
+
+	dev_dbg(dev, "%s id:%u mode:%u rgmii_id:%d rmii_clk_ext:%d\n",
+		__func__, if_phy->id, mode, rgmii_id,
+		if_phy->rmii_clock_external);
+
+	regfield = if_phy->fields[PHY_GMII_SEL_PORT_MODE];
+	ret = regmap_field_write(regfield, mode);
+
+	if (soc_data->features & BIT(PHY_GMII_SEL_RGMII_ID_MODE) &&
+	    if_phy->fields[PHY_GMII_SEL_RGMII_ID_MODE]) {
+		regfield = if_phy->fields[PHY_GMII_SEL_RGMII_ID_MODE];
+		ret |= regmap_field_write(regfield, rgmii_id);
+	}
+
+	if (soc_data->features & BIT(PHY_GMII_SEL_RMII_IO_CLK_EN) &&
+	    if_phy->fields[PHY_GMII_SEL_RMII_IO_CLK_EN]) {
+		regfield = if_phy->fields[PHY_GMII_SEL_RMII_IO_CLK_EN];
+		ret |= regmap_field_write(regfield,
+					  if_phy->rmii_clock_external);
+	}
+
+	if (ret) {
+		dev_err(dev, "port%u: set mode fail %d", if_phy->id, ret);
+		return -EIO;
+	}

I would prefer each write had its own error check. The fact you don't
return ret means you know ret could be -EINVAL|-EOIO, making
-EMORECOFFEE.

	Andrew