Re: [RESEND v4 2/2] PCI: imx: clear vreg bypass when pcie vph voltage is 3v3
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-05-06 21:09:22
Also in:
linux-pci, lkml
On Tue, Mar 30, 2021 at 04:08:21PM +0800, Richard Zhu wrote:
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.
Maybe something like this? PCI: imx6: Enable PHY internal regulator when supplied >3V The i.MX8MQ PCIe PHY needs 1.8V but can by supplied by either a 1.8V or a 3.3V regulator. The "vph-supply" DT property tells us which external regulator supplies the PHY. If that regulator supplies anything over 3V, enable the PHY's internal 3.3V-to-1.8V regulator.
quoted hunk ↗ jump to hunk
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com> Reviewed-by: Lucas Stach <l.stach@pengutronix.de> --- drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c index 853ea8e82952..94b43b4ecca1 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 */@@ -621,6 +623,17 @@ 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 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 && + regulator_get_voltage(imx6_pcie->vph) > 3000000) + regmap_update_bits(imx6_pcie->iomuxc_gpr, + imx6_pcie_grp_offset(imx6_pcie), + IMX8MQ_GPR_PCIE_VREG_BYPASS, + 0); break; case IMX7D: regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,@@ -1130,6 +1143,13 @@ 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);-- 2.17.1
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