netdev - Re: [PATCH v2 1/5] net: mdio: ipq4019: move eth_ldo

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Date: Tue, 12 Dec 2023 13:50:01 +0100
From: Maxime Chevallier <maxime.chevallier@...tlin.com>
To: Luo Jie <quic_luoj@...cinc.com>
Cc: <agross@...nel.org>, <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
 <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
 <pabeni@...hat.com>, <robh+dt@...nel.org>,
 <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
 <andrew@...n.ch>, <hkallweit1@...il.com>, <linux@...linux.org.uk>,
 <robert.marko@...tura.hr>, <linux-arm-msm@...r.kernel.org>,
 <netdev@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <quic_srichara@...cinc.com>
Subject: Re: [PATCH v2 1/5] net: mdio: ipq4019: move eth_ldo_rdy before MDIO
 bus register

Hello,

On Tue, 12 Dec 2023 19:51:46 +0800
Luo Jie <quic_luoj@...cinc.com> wrote:

> The ethernet LDO provides the clock for the ethernet PHY that
> is connected with PCS, each LDO enables the clock output to
> each PCS, after the clock output enablement, the PHY GPIO reset
> can take effect.
> 
> For the PHY taking the MDIO bus level GPIO reset, the ethernet
> LDO should be enabled before the MDIO bus register.
> 
> For example, the qca8084 PHY takes the MDIO bus level GPIO
> reset for quad PHYs, there is another reason for qca8084 PHY
> using MDIO bus level GPIO reset instead of PHY level GPIO
> reset as below.
> 
> The work sequence of qca8084:
> 1. enable ethernet LDO.
> 2. GPIO reset on quad PHYs.
> 3. register clock provider based on MDIO device of qca8084.
> 4. PHY probe function called for initializing common clocks.
> 5. PHY capabilities acquirement.
> 
> If qca8084 takes PHY level GPIO reset in the step 4, the clock
> provider of qca8084 can't be registered correctly, since the
> clock parent(reading the current qca8084 hardware registers in
> step 3) of the registered clocks is deserted after GPIO reset.
> 
> There are two PCS(UNIPHY) supported in SOC side on ipq5332,
> and three PCS(UNIPHY) supported on ipq9574.
> 
> Signed-off-by: Luo Jie <quic_luoj@...cinc.com>
> ---

[...]

> @@ -252,11 +244,32 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
>  	if (IS_ERR(priv->mdio_clk))
>  		return PTR_ERR(priv->mdio_clk);
>  
> -	/* The platform resource is provided on the chipset IPQ5018 */
> -	/* This resource is optional */
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> -	if (res)
> -		priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
> +	/* These platform resources are provided on the chipset IPQ5018 or
> +	 * IPQ5332.
> +	 */
> +	/* This resource are optional */
> +	for (index = 0; index < ETH_LDO_RDY_CNT; index++) {
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, index + 1);
> +		if (res) {
> +			priv->eth_ldo_rdy[index] = devm_ioremap(&pdev->dev,
> +								res->start,
> +								resource_size(res));

You can simplify that sequence by using
devm_platform_get_and_ioremap_resource(), which will do both the
platform_get_resource and the devm_ioremap at once for you.

Thanks,

Maxime