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

On 8/8/2021 11:27 PM, Andrew Lunn wrote:

quoted

+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

quoted

@@ -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.

quoted

+
+	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

quoted

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

is actually wrong, should simply become

quoted

+	if (priv->eth_ldo_rdy) {

   Andrew

Hi Andrew,

Thanks for the kindly review and the comments, will follow it in the 
next patch set.