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

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Message-ID: <a698552a-0bc2-c0d4-d6f8-0d70c50373bb@codeaurora.org>
Date:   Mon, 9 Aug 2021 21:01:36 +0800
From:   Jie Luo <luoj@...eaurora.org>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     hkallweit1@...il.com, davem@...emloft.net, kuba@...nel.org,
        linux@...linux.org.uk, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, sricharan@...eaurora.org
Subject: 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:
>> +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

Hi Andrew,

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