Re: [PATCH v4 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x

Vladimir Oltean
2021-10-07T20:00:16Z

On Thu, Oct 07, 2021 at 08:41:55PM +0530, Prasanna Vengateshan wrote:
> +static int lan937x_mdio_register(struct dsa_switch *ds)
> +{
> + struct device_node *mdio_np;
> + int ret;
> +
> + mdio_np = of_get_child_by_name(ds->dev->of_node, "mdio");
> + if (!mdio_np) {
> + dev_err(ds->dev, "no MDIO bus node\n");
> + return -ENODEV;
> + }
> +
> + ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
> + if (!ds->slave_mii_bus)
> + return -ENOMEM;
> +
> + ds->slave_mii_bus->priv = ds->priv;
> + ds->slave_mii_bus->read = lan937x_sw_mdio_read;
> + ds->slave_mii_bus->write = lan937x_sw_mdio_write;
> + ds->slave_mii_bus->name = "lan937x slave smi";
> + snprintf(ds->slave_mii_bus->id, MII_BUS_ID_SIZE, "SMI-%d", ds->index);
> + ds->slave_mii_bus->parent = ds->dev;
> + ds->slave_mii_bus->phy_mask = ~ds->phys_mii_mask;
> +
> + ret = of_mdiobus_register(ds->slave_mii_bus, mdio_np);

Please use devm_of_mdiobus_register if you're going to use
devm_mdiobus_alloc, or no devres at all.
https://patchwork.kernel.org/project/netdevbpf/patch/20210920214209.1733768-3-vladimir.oltean@nxp.com/

> + if (ret) {
> + dev_err(ds->dev, "unable to register MDIO bus %s\n",
> + ds->slave_mii_bus->id);
> + }
> +
> + of_node_put(mdio_np);
> +
> + return ret;
> +}
> +
> +static phy_interface_t lan937x_get_interface(struct ksz_device *dev, int port)
> +{
> + phy_interface_t interface;
> + u8 data8;
> + int ret;
> +
> + if (lan937x_is_internal_phy_port(dev, port))
> + return PHY_INTERFACE_MODE_NA;

Typically we use PHY_INTERFACE_MODE_INTERNAL.

> +
> + /* read interface from REG_PORT_XMII_CTRL_1 register */
> + ret = lan937x_pread8(dev, port, REG_PORT_XMII_CTRL_1, &data8);
> + if (ret < 0)
> + return PHY_INTERFACE_MODE_NA;
> +
> + switch (data8 & PORT_MII_SEL_M) {
> + case PORT_RMII_SEL:
> + interface = PHY_INTERFACE_MODE_RMII;
> + break;
> + case PORT_RGMII_SEL:
> + interface = PHY_INTERFACE_MODE_RGMII;
> + if (data8 & PORT_RGMII_ID_EG_ENABLE)
> + interface = PHY_INTERFACE_MODE_RGMII_TXID;
> + if (data8 & PORT_RGMII_ID_IG_ENABLE) {
> + interface = PHY_INTERFACE_MODE_RGMII_RXID;
> + if (data8 & PORT_RGMII_ID_EG_ENABLE)
> + interface = PHY_INTERFACE_MODE_RGMII_ID;
> + }
> + break;
> + case PORT_MII_SEL:
> + default:
> + /* Interface is MII */
> + interface = PHY_INTERFACE_MODE_MII;
> + break;
> + }
> +
> + return interface;
> +}
> +
> +static void lan937x_config_cpu_port(struct dsa_switch *ds)
> +{
> + struct ksz_device *dev = ds->priv;
> + struct ksz_port *p;
> + int i;
> +
> + ds->num_ports = dev->port_cnt;
> +
> + for (i = 0; i < dev->port_cnt; i++) {
> + if (dsa_is_cpu_port(ds, i) && (dev->cpu_ports & (1 << i))) {
> + phy_interface_t interface;
> +
> + dev->cpu_port = i;
> + dev->host_mask = (1 << dev->cpu_port);
> + dev->port_mask |= dev->host_mask;
> + p = &dev->ports[i];
> +
> + /* Check if the device tree have specific interface
> + * setting otherwise read & assign from XMII register
> + * for host port interface
> + */
> + interface = lan937x_get_interface(dev, i);

What does the CPU port have so special that you override it here?
Again some compatibility with out-of-tree DT bindings?

> + if (!p->interface)
> + p->interface = interface;
> +
> + dev_info(dev->dev,
> + "Port%d: using phy mode %s\n",
> + i,
> + phy_modes(p->interface));
> +
> + /* enable cpu port */
> + lan937x_port_setup(dev, i, true);
> + p->vid_member = dev->port_mask;
> + }
> + }
> +
> +static u8 lan937x_rgmii_dly_reg_val(int port, u32 val)
> +{
> + u8 reg_val;
> +
> + /* force minimum delay if delay is less than min delay */
> + if (val && val < 2170)
> + val = 2170;
> +
> + /* maximum delay is 4ns */
> + if (val > 4000)
> + val = 4000;

These bindings are new. Given that you also document their min and max
values, why don't you just error out on out-of-range values instead of
silently doing what you think is going to be fine?