--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Meson GXL USB3 PHY and OTG mode detection driver
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/platform_device.h>
+
+#define USB_R0                                                 0x00
+       #define USB_R0_P30_FSEL_MASK                            GENMASK(5, 0)
+       #define USB_R0_P30_PHY_RESET                            BIT(6)
+       #define USB_R0_P30_TEST_POWERDOWN_HSP                   BIT(7)
+       #define USB_R0_P30_TEST_POWERDOWN_SSP                   BIT(8)
+       #define USB_R0_P30_ACJT_LEVEL_MASK                      GENMASK(13, 9)
+       #define USB_R0_P30_TX_BOOST_LEVEL_MASK                  GENMASK(16, 14)
+       #define USB_R0_P30_LANE0_TX2RX_LOOPBACK                 BIT(17)
+       #define USB_R0_P30_LANE0_EXT_PCLK_REQ                   BIT(18)
+       #define USB_R0_P30_PCS_RX_LOS_MASK_VAL_MASK             GENMASK(28, 19)
+       #define USB_R0_U2D_SS_SCALEDOWN_MODE_MASK               GENMASK(30, 29)
+       #define USB_R0_U2D_ACT                                  BIT(31)
+
+#define USB_R1                                                 0x04
+       #define USB_R1_U3H_BIGENDIAN_GS                         BIT(0)
+       #define USB_R1_U3H_PME_ENABLE                           BIT(1)
+       #define USB_R1_U3H_HUB_PORT_OVERCURRENT_MASK            GENMASK(6, 2)
+       #define USB_R1_U3H_HUB_PORT_PERM_ATTACH_MASK            GENMASK(11, 7)
+       #define USB_R1_U3H_HOST_U2_PORT_DISABLE_MASK            GENMASK(15, 12)
+       #define USB_R1_U3H_HOST_U3_PORT_DISABLE                 BIT(16)
+       #define USB_R1_U3H_HOST_PORT_POWER_CONTROL_PRESENT      BIT(17)
+       #define USB_R1_U3H_HOST_MSI_ENABLE                      BIT(18)
+       #define USB_R1_U3H_FLADJ_30MHZ_REG_MASK                 GENMASK(24, 19)
+       #define USB_R1_P30_PCS_TX_SWING_FULL_MASK               GENMASK(31, 25)
+
+#define USB_R2                                                 0x08
+       #define USB_R2_P30_CR_DATA_IN_MASK                      GENMASK(15, 0)
+       #define USB_R2_P30_CR_READ                              BIT(16)
+       #define USB_R2_P30_CR_WRITE                             BIT(17)
+       #define USB_R2_P30_CR_CAP_ADDR                          BIT(18)
+       #define USB_R2_P30_CR_CAP_DATA                          BIT(19)
+       #define USB_R2_P30_PCS_TX_DEEMPH_3P5DB_MASK             GENMASK(25, 20)
+       #define USB_R2_P30_PCS_TX_DEEMPH_6DB_MASK               GENMASK(31, 26)
+
+#define USB_R3                                                 0x0c
+       #define USB_R3_P30_SSC_ENABLE                           BIT(0)
+       #define USB_R3_P30_SSC_RANGE_MASK                       GENMASK(3, 1)
+       #define USB_R3_P30_SSC_REF_CLK_SEL_MASK                 GENMASK(12, 4)
+       #define USB_R3_P30_REF_SSP_EN                           BIT(13)
+       #define USB_R3_P30_LOS_BIAS_MASK                        GENMASK(18, 16)
+       #define USB_R3_P30_LOS_LEVEL_MASK                       GENMASK(23, 19)
+       #define USB_R3_P30_MPLL_MULTIPLIER_MASK                 GENMASK(30, 24)
+
+#define USB_R4                                                 0x10
+       #define USB_R4_P21_PORT_RESET_0                         BIT(0)
+       #define USB_R4_P21_SLEEP_M0                             BIT(1)
+       #define USB_R4_MEM_PD_MASK                              GENMASK(3, 2)
+       #define USB_R4_P21_ONLY                                 BIT(4)
+
+#define USB_R5                                                 0x14
+       #define USB_R5_ID_DIG_SYNC                              BIT(0)
+       #define USB_R5_ID_DIG_REG                               BIT(1)
+       #define USB_R5_ID_DIG_CFG_MASK                          GENMASK(3, 2)
+       #define USB_R5_ID_DIG_EN_0                              BIT(4)
+       #define USB_R5_ID_DIG_EN_1                              BIT(5)
+       #define USB_R5_ID_DIG_CURR                              BIT(6)
+       #define USB_R5_ID_DIG_IRQ                               BIT(7)
+       #define USB_R5_ID_DIG_TH_MASK                           GENMASK(15, 8)
+       #define USB_R5_ID_DIG_CNT_MASK                          GENMASK(23, 16)
+
+/* read-only register */
+#define USB_R6                                                 0x18
+       #define USB_R6_P30_CR_DATA_OUT_MASK                     GENMASK(15, 0)
+       #define USB_R6_P30_CR_ACK                               BIT(16)
+
+struct phy_meson_gxl_usb3_priv {
+       struct regmap           *regmap;
+       enum phy_mode           mode;
+       struct clk              *clk_phy;
+       struct clk              *clk_peripheral;
+       struct reset_control    *reset;
+};
+
+static const struct regmap_config phy_meson_gxl_usb3_regmap_conf = {
+       .reg_bits = 8,
+       .val_bits = 32,
+       .reg_stride = 4,
+       .max_register = USB_R6,
+};
+
+static int phy_meson_gxl_usb3_power_on(struct phy *phy)
+{
+       struct phy_meson_gxl_usb3_priv *priv = phy_get_drvdata(phy);
+
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_EN_0,
+                          USB_R5_ID_DIG_EN_0);
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_EN_1,
+                          USB_R5_ID_DIG_EN_1);
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_TH_MASK,
+                          FIELD_PREP(USB_R5_ID_DIG_TH_MASK, 0xff));
+
+       return 0;
+}
+
+static int phy_meson_gxl_usb3_power_off(struct phy *phy)
+{
+       struct phy_meson_gxl_usb3_priv *priv = phy_get_drvdata(phy);
+
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_EN_0, 0);
+       regmap_update_bits(priv->regmap, USB_R5, USB_R5_ID_DIG_EN_1, 0);
+
+       return 0;
+}
+
+static int phy_meson_gxl_usb3_set_mode(struct phy *phy, enum phy_mode mode)
+{
+       struct phy_meson_gxl_usb3_priv *priv = phy_get_drvdata(phy);
+
+       switch (mode) {
+       case PHY_MODE_USB_HOST:
+               regmap_update_bits(priv->regmap, USB_R0, USB_R0_U2D_ACT, 0);
+               regmap_update_bits(priv->regmap, USB_R4, USB_R4_P21_SLEEP_M0,
+                                  0);
+               break;
+
+       case PHY_MODE_USB_DEVICE:
+               regmap_update_bits(priv->regmap, USB_R0, USB_R0_U2D_ACT,
+                                  USB_R0_U2D_ACT);
+               regmap_update_bits(priv->regmap, USB_R4, USB_R4_P21_SLEEP_M0,
+                                  USB_R4_P21_SLEEP_M0);
+               break;
+
+       default:
+               dev_err(&phy->dev, "unsupported PHY mode %d\n", mode);
+               return -EINVAL;
+       }
+
+       priv->mode = mode;
+
+       return 0;
+}
+
+static int phy_meson_gxl_usb3_init(struct phy *phy)
+{
+       struct phy_meson_gxl_usb3_priv *priv = phy_get_drvdata(phy);
+       int ret;
+
+       ret = reset_control_reset(priv->reset);
+       if (ret)
+               goto err;
+
+       ret = clk_prepare_enable(priv->clk_phy);
+       if (ret)
+               goto err;
+
+       ret = clk_prepare_enable(priv->clk_peripheral);
+       if (ret)
+               goto err_disable_clk_phy;
+
+       ret = phy_meson_gxl_usb3_set_mode(phy, priv->mode);
+       if (ret)
+               goto err_disable_clk_peripheral;
+
+       regmap_update_bits(priv->regmap, USB_R1,
+                          USB_R1_U3H_FLADJ_30MHZ_REG_MASK,
+                          FIELD_PREP(USB_R1_U3H_FLADJ_30MHZ_REG_MASK, 0x20));
+
+       return 0;
+
+err_disable_clk_peripheral:
+       clk_disable_unprepare(priv->clk_peripheral);
+err_disable_clk_phy:
+       clk_disable_unprepare(priv->clk_phy);
+err:
+       return ret;
+}
+
+static int phy_meson_gxl_usb3_exit(struct phy *phy)
+{
+       struct phy_meson_gxl_usb3_priv *priv = phy_get_drvdata(phy);
+
+       clk_disable_unprepare(priv->clk_peripheral);
+       clk_disable_unprepare(priv->clk_phy);
+
+       return 0;
+}
+
+static const struct phy_ops phy_meson_gxl_usb3_ops = {
+       .power_on       = phy_meson_gxl_usb3_power_on,
+       .power_off      = phy_meson_gxl_usb3_power_off,
+       .set_mode       = phy_meson_gxl_usb3_set_mode,
+       .init           = phy_meson_gxl_usb3_init,
+       .exit           = phy_meson_gxl_usb3_exit,
+       .owner          = THIS_MODULE,
+};
+
+static int phy_meson_gxl_usb3_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct phy_meson_gxl_usb3_priv *priv;
+       struct resource *res;
+       struct phy *phy;
+       struct phy_provider *phy_provider;
+       void __iomem *base;
+       int ret;
+
+       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+
+       priv->regmap = devm_regmap_init_mmio(dev, base,
+                                            &phy_meson_gxl_usb3_regmap_conf);
+       if (IS_ERR(priv->regmap))
+               return PTR_ERR(priv->regmap);
+
+       priv->clk_phy = devm_clk_get(dev, "phy");
+       if (IS_ERR(priv->clk_phy))
+               return PTR_ERR(priv->clk_phy);
+
+       priv->clk_peripheral = devm_clk_get(dev, "peripheral");
+       if (IS_ERR(priv->clk_peripheral))
+               return PTR_ERR(priv->clk_peripheral);
+
+       priv->reset = devm_reset_control_array_get_shared(dev);
+       if (IS_ERR(priv->reset))
+               return PTR_ERR(priv->reset);
+
+       /*
+        * default to host mode as hardware defaults and/or boot-loader
+        * behavior can result in this PHY starting up in device mode. this
+        * default and the initialization in phy_meson_gxl_usb3_init ensure
+        * that we reproducibly start in a known mode on all devices.
+        */
+       priv->mode = PHY_MODE_USB_HOST;
+
+       phy = devm_phy_create(dev, np, &phy_meson_gxl_usb3_ops);
+       if (IS_ERR(phy)) {
+               ret = PTR_ERR(phy);
+               if (ret != -EPROBE_DEFER)
+                       dev_err(dev, "failed to create PHY\n");
+
+               return ret;
+       }
+
+       phy_set_drvdata(phy, priv);
+
+       phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+       return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id phy_meson_gxl_usb3_of_match[] = {
+       { .compatible = "amlogic,meson-gxl-usb3-phy", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, phy_meson_gxl_usb3_of_match);
+
+static struct platform_driver phy_meson_gxl_usb3_driver = {
+       .probe  = phy_meson_gxl_usb3_probe,
+       .driver = {
+               .name           = "phy-meson-gxl-usb3",
+               .of_match_table = phy_meson_gxl_usb3_of_match,
+       },
+};
+module_platform_driver(phy_meson_gxl_usb3_driver);
+
+MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
+MODULE_DESCRIPTION("Meson GXL USB3 PHY and OTG detection driver");
+MODULE_LICENSE("GPL v2");