Am Mittwoch, dem 24.03.2021 um 13:34 +0800 schrieb Richard Zhu:
> Both 1.8v and 3.3v power supplies can be used by i.MX8MQ PCIe PHY.
> In default, the PCIE_VPH voltage is suggested to be 1.8v refer to data
> sheet. When PCIE_VPH is supplied by 3.3v in the HW schematic design,
> the VREG_BYPASS bits of GPR registers should be cleared from default
> value 1b'1 to 1b'0. Thus, the internal 3v3 to 1v8 translator would be
> turned on.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 853ea8e82952..beca085a9300 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -37,6 +37,7 @@
> #define IMX8MQ_GPR_PCIE_REF_USE_PAD BIT(9)
> #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN BIT(10)
> #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE BIT(11)
> +#define IMX8MQ_GPR_PCIE_VREG_BYPASS BIT(12)
> #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE GENMASK(11, 8)
> #define IMX8MQ_PCIE2_BASE_ADDR 0x33c00000
>
>
>
>
> @@ -80,6 +81,7 @@ struct imx6_pcie {
> u32 tx_swing_full;
> u32 tx_swing_low;
> struct regulator *vpcie;
> + struct regulator *vph;
> void __iomem *phy_base;
>
>
>
>
> /* power domain for pcie */
> @@ -611,6 +613,8 @@ static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
>
>
>
>
> static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
> {
> + int phy_uv;
> +
No need for this variable...
> switch (imx6_pcie->drvdata->variant) {
> case IMX8MQ:
> /*
> @@ -621,6 +625,18 @@ static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
> imx6_pcie_grp_offset(imx6_pcie),
> IMX8MQ_GPR_PCIE_REF_USE_PAD,
> IMX8MQ_GPR_PCIE_REF_USE_PAD);
> + /*
> + * Regarding to the datasheet, the PCIE_VPH is suggested
> + * to be 1.8V. If the PCIE_VPH is supplied by 3.3V, the
> + * VREG_BYPASS should be cleared to zero.
> + */
> + if (imx6_pcie->vph)
> + phy_uv = regulator_get_voltage(imx6_pcie->vph);
> + if (phy_uv > 3000000)
> + regmap_update_bits(imx6_pcie->iomuxc_gpr,
> + imx6_pcie_grp_offset(imx6_pcie),
> + IMX8MQ_GPR_PCIE_VREG_BYPASS,
> + 0);
...if you just fold this into a single condition. Right now phy_uv
might be used uninitialized when the vph-supply is not specified in the
DT. Better write this as:
if (imx6_pcie->vph && regulator_get_voltage(imx6_pcie->vph) > 3000000)
Regards,
Lucas
> break;
> case IMX7D:
> regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
> @@ -1130,6 +1146,13 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> imx6_pcie->vpcie = NULL;
> }
>
>
>
>
>
>
>
>
> + imx6_pcie->vph = devm_regulator_get_optional(&pdev->dev, "vph");
> + if (IS_ERR(imx6_pcie->vph)) {
> + if (PTR_ERR(imx6_pcie->vph) != -ENODEV)
> + return PTR_ERR(imx6_pcie->vph);
> + imx6_pcie->vph = NULL;
> + }
> +
> platform_set_drvdata(pdev, imx6_pcie);
>
>
>
>
>
>
>
>
> ret = imx6_pcie_attach_pd(dev);
