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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Wed, 14 Jun 2023 09:18:06 +0200
Message-ID: <CAMRc=MdwqF9_LM2BeVOtx+DaKv8Cv8Bp-cP=sE-RBO=UoosSLg@mail.gmail.com>
Subject: Re: [PATCH 03/26] phy: qcom: add the SGMII SerDes PHY driver
To:     Konrad Dybcio <konrad.dybcio@linaro.org>
Cc:     Vinod Koul <vkoul@kernel.org>,
        Bhupesh Sharma <bhupesh.sharma@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>, netdev@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org,
        linux-stm32@st-md-mailman.stormreply.com,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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On Mon, Jun 12, 2023 at 11:45=E2=80=AFAM Konrad Dybcio <konrad.dybcio@linar=
o.org> wrote:
>
>
>
> On 12.06.2023 11:23, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Implement support for the SGMII/SerDes PHY present on various Qualcomm
> > platforms.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> > +static const struct regmap_config qcom_dwmac_sgmii_phy_regmap_cfg =3D =
{
> > +     .reg_bits               =3D 32,
> > +     .val_bits               =3D 32,
> > +     .reg_stride             =3D 4,
> > +     .use_relaxed_mmio       =3D true,
> > +     .disable_locking        =3D true,
> The last two are rather brave, no?
>

We don't need locking because all callbacks are already protected by
the phy subsystem with a mutex and I don't really see anything that
would make it dangerous to use relaxed semantics in this driver. It's
just basic configuration.

Bart

> Konrad
> > +};
> > +
> > +static int qcom_dwmac_sgmii_phy_probe(struct platform_device *pdev)
> > +{
> > +     struct qcom_dwmac_sgmii_phy_data *data;
> > +     struct device *dev =3D &pdev->dev;
> > +     struct phy_provider *provider;
> > +     struct clk *refclk;
> > +     void __iomem *base;
> > +     struct phy *phy;
> > +
> > +     data =3D devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> > +     if (!data)
> > +             return -ENOMEM;
> > +
> > +     base =3D devm_platform_ioremap_resource(pdev, 0);
> > +     if (IS_ERR(base))
> > +             return PTR_ERR(base);
> > +
> > +     data->regmap =3D devm_regmap_init_mmio(dev, base,
> > +                                          &qcom_dwmac_sgmii_phy_regmap=
_cfg);
> > +     if (IS_ERR(data->regmap))
> > +             return PTR_ERR(data->regmap);
> > +
> > +     phy =3D devm_phy_create(dev, NULL, &qcom_dwmac_sgmii_phy_ops);
> > +     if (IS_ERR(phy))
> > +             return PTR_ERR(phy);
> > +
> > +     refclk =3D devm_clk_get_enabled(dev, "sgmi_ref");
> > +     if (IS_ERR(refclk))
> > +             return PTR_ERR(refclk);
> > +
> > +     provider =3D devm_of_phy_provider_register(dev, of_phy_simple_xla=
te);
> > +     if (IS_ERR(provider))
> > +             return PTR_ERR(provider);
> > +
> > +     phy_set_drvdata(phy, data);
> > +     platform_set_drvdata(pdev, data);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct of_device_id qcom_dwmac_sgmii_phy_of_match[] =3D {
> > +     { .compatible =3D "qcom,sa8775p-dwmac-sgmii-phy" },
> > +     { },
> > +};
> > +MODULE_DEVICE_TABLE(of, qcom_dwmac_sgmii_phy_of_match);
> > +
> > +static struct platform_driver qcom_dwmac_sgmii_phy_driver =3D {
> > +     .probe  =3D qcom_dwmac_sgmii_phy_probe,
> > +     .driver =3D {
> > +             .name   =3D "qcom-dwmac-sgmii-phy",
> > +             .of_match_table =3D qcom_dwmac_sgmii_phy_of_match,
> > +     }
> > +};
> > +
> > +module_platform_driver(qcom_dwmac_sgmii_phy_driver);
> > +
> > +MODULE_DESCRIPTION("Qualcomm DWMAC SGMII PHY driver");
> > +MODULE_LICENSE("GPL");