linux-kernel - Re: [PATCH v9 17/22] phy: phy-mtk-dp: Add driver for DP phy

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Message-ID: <CABnWg9s7MN_21CEYVJV9=udfYkYQ_huJjQvLf+Jcb3Dmc8pNCA@mail.gmail.com>
Date:   Tue, 12 Apr 2022 02:04:02 -0700
From:   Guillaume Ranquet <granquet@...libre.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>, vkoul@...nel.org,
        airlied@...ux.ie, chunfeng.yun@...iatek.com,
        chunkuang.hu@...nel.org, ck.hu@...iatek.com, daniel@...ll.ch,
        deller@....de, jitao.shi@...iatek.com, kishon@...com,
        krzk+dt@...nel.org, maarten.lankhorst@...ux.intel.com,
        matthias.bgg@...il.com, mripard@...nel.org, p.zabel@...gutronix.de,
        robh+dt@...nel.org, tzimmermann@...e.de
Cc:     devicetree@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-fbdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-phy@...ts.infradead.org, markyacoub@...gle.com,
        Markus Schneider-Pargmann <msp@...libre.com>
Subject: Re: [PATCH v9 17/22] phy: phy-mtk-dp: Add driver for DP phy

On Mon, 28 Mar 2022 10:20, AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com> wrote:
>Il 28/03/22 00:39, Guillaume Ranquet ha scritto:
>> From: Markus Schneider-Pargmann <msp@...libre.com>
>>
>> This is a new driver that supports the integrated DisplayPort phy for
>> mediatek SoCs, especially the mt8195. The phy is integrated into the
>> DisplayPort controller and will be created by the mtk-dp driver. This
>> driver expects a struct regmap to be able to work on the same registers
>> as the DisplayPort controller. It sets the device data to be the struct
>> phy so that the DisplayPort controller can easily work with it.
>>
>> The driver does not have any devicetree bindings because the datasheet
>> does not list the controller and the phy as distinct units.
>>
>> The interaction with the controller can be covered by the configure
>> callback of the phy framework and its displayport parameters.
>>
>> Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
>> Signed-off-by: Guillaume Ranquet <granquet@...libre.com>
>> ---
>>   MAINTAINERS                       |   1 +
>>   drivers/phy/mediatek/Kconfig      |   8 ++
>>   drivers/phy/mediatek/Makefile     |   1 +
>>   drivers/phy/mediatek/phy-mtk-dp.c | 201 ++++++++++++++++++++++++++++++
>>   4 files changed, 211 insertions(+)
>>   create mode 100644 drivers/phy/mediatek/phy-mtk-dp.c
>>
>
>..snip..
>
>> diff --git a/drivers/phy/mediatek/phy-mtk-dp.c b/drivers/phy/mediatek/phy-mtk-dp.c
>> new file mode 100644
>> index 000000000000..e5c5494f3636
>> --- /dev/null
>> +++ b/drivers/phy/mediatek/phy-mtk-dp.c
>
>..snip..
>
>> +
>> +static int mtk_dp_phy_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct mtk_dp_phy *dp_phy;
>> +	struct phy *phy;
>> +	struct regmap *regs;
>> +
>> +	regs = syscon_regmap_lookup_by_phandle(dev->of_node, "mediatek,dp-syscon");
>> +
>
>Please drop this blank line
>
>> +	if (IS_ERR(regs))
>> +		return PTR_ERR(regs);
>> +
>> +	dp_phy = devm_kzalloc(dev, sizeof(*dp_phy), GFP_KERNEL);
>> +	if (!dp_phy)
>> +		return -ENOMEM;
>> +
>> +	dp_phy->regs = regs;
>> +
>> +	phy = devm_phy_create(dev, NULL, &mtk_dp_phy_dev_ops);
>> +
>
>Same here
>
>> +	if (IS_ERR(phy))
>> +		return dev_err_probe(dev, PTR_ERR(phy), "Failed to create DP PHY: %ld\n", PTR_ERR(phy));
>> +
>
>Using dev_err_probe automates printing the error, so the correct usage is:
>
>return dev_err_probe(dev, PTR_ERR(phy), "Failed to create DP PHY\n");
>
>> +	phy_set_drvdata(phy, dp_phy);
>> +
>> +	return 0;
>> +}
>> +
>> +struct platform_driver mtk_dp_phy_driver = {
>> +	.probe = mtk_dp_phy_probe,
>> +	.driver = {
>> +		.name = "mediatek-dp-phy",
>> +	},
>> +};
>> +module_platform_driver(mtk_dp_phy_driver);
>
>Also, in your dt-binding, you mention a compatible for this driver, but I don't see
>any, here. This means that you do know what to do, so please do it.
>

Following the comments from rob [1], I'll revert back to using
platform_device_register_data() from v8.

[1] https://lore.kernel.org/linux-mediatek/YkOPB5W7uXkOc72%2F@robh.at.kernel.org/

>Regards,
>Angelo
>
>> +
>> +MODULE_AUTHOR("Markus Schneider-Pargmann <msp@...libre.com>");
>> +MODULE_DESCRIPTION("MediaTek DP PHY Driver");
>> +MODULE_LICENSE("GPL");
>