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

Andrew Lunn
2018-10-09T00:39:35Z

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