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

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Date: Tue, 12 Dec 2023 19:11:15 +0000
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Maxime Chevallier <maxime.chevallier@...tlin.com>
Cc: Luo Jie <quic_luoj@...cinc.com>, 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,
	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

On Tue, Dec 12, 2023 at 01:50:01PM +0100, Maxime Chevallier wrote:
> Hello,
> 
> On Tue, 12 Dec 2023 19:51:46 +0800
> Luo Jie <quic_luoj@...cinc.com> wrote:
> > @@ -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.

Sadly it can't if resources are optional. __devm_ioremap_resource()
which will be capped by devm_platform_get_and_ioremap_resource() will
be passed a NULL 'res', which will lead to:

        if (!res || resource_type(res) != IORESOURCE_MEM) {
                dev_err(dev, "invalid resource %pR\n", res);
                return IOMEM_ERR_PTR(-EINVAL);
        }

There isn't an "optional" version of
devm_platform_get_and_ioremap_resource().

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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