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Subject[PATCH v5 2/2] PCI: imx6: Enable PHY internal regulator when supplied >3V
Date
The i.MX8MQ PCIe PHY needs 1.8V in default but can be 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.

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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