linux-kernel - Re: [PATCH v8 2/2] phy: mediatek: Add PCIe PHY driver

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Date:   Wed, 18 May 2022 10:21:20 +0800
From:   Jianjun Wang <jianjun.wang@...iatek.com>
To:     Rex-BC Chen <rex-bc.chen@...iatek.com>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        "Vinod Koul" <vkoul@...nel.org>, Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Chen-Yu Tsai <wenst@...omium.org>,
        "AngeloGioacchino Del Regno" 
        <angelogioacchino.delregno@...labora.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
CC:     Wei-Shun Chang <weishunc@...gle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-phy@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <randy.wu@...iatek.com>,
        <jieyy.yang@...iatek.com>, <chuanjia.liu@...iatek.com>,
        <qizhong.cheng@...iatek.com>, <jian.yang@...iatek.com>
Subject: Re: [PATCH v8 2/2] phy: mediatek: Add PCIe PHY driver

On Wed, 2022-05-11 at 11:22 +0800, Rex-BC Chen wrote:
> On Sat, 2022-05-07 at 14:06 +0800, Jianjun Wang wrote:
> > Add PCIe GEN3 PHY driver support on MediaTek chipsets.
> > 
> > +
> > +static int mtk_pcie_phy_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct phy_provider *provider;
> > +	struct mtk_pcie_phy *pcie_phy;
> > +	int ret;
> > +
> > +	pcie_phy = devm_kzalloc(dev, sizeof(*pcie_phy), GFP_KERNEL);
> > +	if (!pcie_phy)
> > +		return -ENOMEM;
> > +
> > +	pcie_phy->sif_base =
> > devm_platform_ioremap_resource_byname(pdev, "sif");
> > +	if (IS_ERR(pcie_phy->sif_base))
> > +		return dev_err_probe(dev, PTR_ERR(pcie_phy->sif_base),
> > +				     "Failed to map phy-sif base\n");
> > +
> > +	pcie_phy->phy = devm_phy_create(dev, dev->of_node,
> > &mtk_pcie_phy_ops);
> > +	if (IS_ERR(pcie_phy->phy))
> > +		return dev_err_probe(dev, PTR_ERR(pcie_phy->phy),
> > +				     "Failed to create PCIe phy\n");
> > +
> > +	pcie_phy->dev = dev;
> > +	pcie_phy->data = of_device_get_match_data(dev);
> > +	if (!pcie_phy->data)
> > +		return dev_err_probe(dev, -EINVAL, "Failed to get phy
> > data\n");
> > +
> > +	if (pcie_phy->data->sw_efuse_supported) {
> > +		/*
> > +		 * Failed to read the efuse data is not a fatal
> > problem,
> > +		 * ignore the failure and keep going.
> > +		 */
> > +		ret = mtk_pcie_read_efuse(pcie_phy);
> > +		if (ret == -EPROBE_DEFER)
> > +			return ret;
> 
> Hello Jianjun,
> 
> even though it's not a fatal problem if we can not read efuse, but I
> tink "ret = -ENOMEM" does not mean we can't read it?
> 
> Do we need to handle this?

Yes, I think we should handle it in this case, I'll fix it in the next
version, thanks for your review.

Thanks.

> 
> BRs,
> Rex
> > +	}
> > +
> > +	phy_set_drvdata(pcie_phy->phy, pcie_phy);
> > +
> > +	provider = devm_of_phy_provider_register(dev,
> > of_phy_simple_xlate);
> > +	if (IS_ERR(provider))
> > +		return dev_err_probe(dev, PTR_ERR(provider),
> > +				     "PCIe phy probe failed\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct mtk_pcie_phy_data mt8195_data = {
> > +	.num_lanes = 2,
> > +	.sw_efuse_supported = true,
> > +};
> > +
> > +static const struct of_device_id mtk_pcie_phy_of_match[] = {
> > +	{ .compatible = "mediatek,mt8195-pcie-phy", .data =
> > &mt8195_data },
> > +	{ },
> > +};
> > +MODULE_DEVICE_TABLE(of, mtk_pcie_phy_of_match);
> > +
> > +static struct platform_driver mtk_pcie_phy_driver = {
> > +	.probe	= mtk_pcie_phy_probe,
> > +	.driver	= {
> > +		.name = "mtk-pcie-phy",
> > +		.of_match_table = mtk_pcie_phy_of_match,
> > +	},
> > +};
> > +module_platform_driver(mtk_pcie_phy_driver);
> > +
> > +MODULE_DESCRIPTION("MediaTek PCIe PHY driver");
> > +MODULE_AUTHOR("Jianjun Wang <jianjun.wang@...iatek.com>");
> > +MODULE_LICENSE("GPL");
> 
>