Re: [PATCH v1 1/2] net: mdio: Add the reset function for IPQ MDIO driver

Andrew Lunn
2021-08-08T15:27:15Z

> +static int ipq_mdio_reset(struct mii_bus *bus)
> +{
> + struct ipq4019_mdio_data *priv = bus->priv;
> + u32 val;
> + int ret;
> +
> + /* To indicate CMN_PLL that ethernet_ldo has been ready if platform resource 1
> + * is specified in the device tree.
> + * */
> + if (!IS_ERR(priv->eth_ldo_rdy)) {
> + val = readl(priv->eth_ldo_rdy);
> + val |= BIT(0);
> + writel(val, priv->eth_ldo_rdy);
> + fsleep(IPQ_PHY_SET_DELAY_US);
> + }
> +
> + /* Configure MDIO clock source frequency if clock is specified in the device tree */
> + if (!IS_ERR_OR_NULL(priv->mdio_clk)) {
> + ret = clk_set_rate(priv->mdio_clk, IPQ_MDIO_CLK_RATE);
> + if (ret)
> + return ret;
> +
> + ret = clk_prepare_enable(priv->mdio_clk);
> + if (ret)
> + return ret;
> + }

These !IS_ERR() are pretty ugly. So

> @@ -182,14 +221,22 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> priv = bus->priv;
> + priv->eth_ldo_rdy = IOMEM_ERR_PTR(-EINVAL);
>
> priv->membase = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(priv->membase))
> return PTR_ERR(priv->membase);
>
> + priv->mdio_clk = devm_clk_get_optional(&pdev->dev, "gcc_mdio_ahb_clk");

If this returns an error, it is a real error. You should not ignore
it. Fail the probe returning the error. That then means when the reset
function is called priv->mdio_clk contains either a clock, or NULL,
which the clk API is happy to take. No need for an if.

> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> + if (res)
> + priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);

platform_get_resource() returns a pointer or NULL. There is no error
code. So

> + if (!IS_ERR(priv->eth_ldo_rdy)) {

is actually wrong, should simply become

> + if (priv->eth_ldo_rdy) {

Andrew