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Message-ID: <4697e3af-86f7-83e0-1737-3f5000fc8d30@collabora.com>
Date:   Mon, 28 Mar 2022 10:20:27 +0200
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Subject: Re: [PATCH v9 17/22] phy: phy-mtk-dp: Add driver for DP phy
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To:     Guillaume Ranquet <granquet@baylibre.com>, airlied@linux.ie,
        chunfeng.yun@mediatek.com, chunkuang.hu@kernel.org,
        ck.hu@mediatek.com, daniel@ffwll.ch, deller@gmx.de,
        jitao.shi@mediatek.com, kishon@ti.com, krzk+dt@kernel.org,
        maarten.lankhorst@linux.intel.com, matthias.bgg@gmail.com,
        mripard@kernel.org, p.zabel@pengutronix.de, robh+dt@kernel.org,
        tzimmermann@suse.de, vkoul@kernel.org
Cc:     devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
        linux-phy@lists.infradead.org, markyacoub@google.com,
        Markus Schneider-Pargmann <msp@baylibre.com>
References: <20220327223927.20848-1-granquet@baylibre.com>
 <20220327223927.20848-18-granquet@baylibre.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20220327223927.20848-18-granquet@baylibre.com>
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Precedence: bulk

Il 28/03/22 00:39, Guillaume Ranquet ha scritto:
> From: Markus Schneider-Pargmann <msp@baylibre.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@baylibre.com>
> Signed-off-by: Guillaume Ranquet <granquet@baylibre.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.

Regards,
Angelo

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