phy: qcom: Add M31 based eUSB2 PHY driver

SM8750 utilizes an eUSB2 PHY from M31. Add the initialization
sequences to bring it out of reset and into an operational state. This
differs to the M31 USB driver, in that the M31 eUSB2 driver will
require a connection to an eUSB2 repeater. This PHY driver will handle
the initialization of the associated eUSB2 repeater when required.

Reviewed-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Wesley Cheng <[email protected]>
Signed-off-by: Melody Olvera <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: Wesley Cheng

drivers/phy/qualcomm/Kconfig

@@ -158,6 +158,16 @@ config PHY_QCOM_UNIPHY_PCIE_28LP
 	  handles PHY initialization, clock management required after
 	  resetting the hardware and power management.
 
+config PHY_QCOM_M31_EUSB
+	tristate "Qualcomm M31 eUSB2 PHY driver support"
+	depends on USB && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable this to support M31 EUSB2 PHY transceivers on Qualcomm
+	  chips with DWC3 USB core. It supports initializing and cleaning
+	  up of the associated USB repeater that is paired with the eUSB2
+	  PHY.
+
 config PHY_QCOM_USB_HS
 	tristate "Qualcomm USB HS PHY module"
 	depends on USB_ULPI_BUS

drivers/phy/qualcomm/Makefile

@@ -5,6 +5,7 @@ obj-$(CONFIG_PHY_QCOM_EDP)		+= phy-qcom-edp.o
 obj-$(CONFIG_PHY_QCOM_IPQ4019_USB)	+= phy-qcom-ipq4019-usb.o
 obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA)	+= phy-qcom-ipq806x-sata.o
 obj-$(CONFIG_PHY_QCOM_M31_USB)		+= phy-qcom-m31.o
+obj-$(CONFIG_PHY_QCOM_M31_EUSB)		+= phy-qcom-m31-eusb2.o
 obj-$(CONFIG_PHY_QCOM_PCIE2)		+= phy-qcom-pcie2.o
 
 obj-$(CONFIG_PHY_QCOM_QMP_COMBO)	+= phy-qcom-qmp-combo.o phy-qcom-qmp-usbc.o

drivers/phy/qualcomm/phy-qcom-m31-eusb2.c

@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include <linux/regulator/consumer.h>
+
+#define USB_PHY_UTMI_CTRL0		(0x3c)
+#define SLEEPM				BIT(0)
+
+#define USB_PHY_UTMI_CTRL5		(0x50)
+#define POR				BIT(1)
+
+#define USB_PHY_HS_PHY_CTRL_COMMON0	(0x54)
+#define SIDDQ_SEL			BIT(1)
+#define SIDDQ				BIT(2)
+#define FSEL				GENMASK(6, 4)
+#define FSEL_38_4_MHZ_VAL		(0x6)
+
+#define USB_PHY_HS_PHY_CTRL2		(0x64)
+#define USB2_SUSPEND_N			BIT(2)
+#define USB2_SUSPEND_N_SEL		BIT(3)
+
+#define USB_PHY_CFG0			(0x94)
+#define UTMI_PHY_CMN_CTRL_OVERRIDE_EN	BIT(1)
+
+#define USB_PHY_CFG1			(0x154)
+#define PLL_EN				BIT(0)
+
+#define USB_PHY_FSEL_SEL		(0xb8)
+#define FSEL_SEL			BIT(0)
+
+#define USB_PHY_XCFGI_39_32		(0x16c)
+#define HSTX_PE				GENMASK(3, 2)
+
+#define USB_PHY_XCFGI_71_64		(0x17c)
+#define HSTX_SWING			GENMASK(3, 0)
+
+#define USB_PHY_XCFGI_31_24		(0x168)
+#define HSTX_SLEW			GENMASK(2, 0)
+
+#define USB_PHY_XCFGI_7_0		(0x15c)
+#define PLL_LOCK_TIME			GENMASK(1, 0)
+
+#define M31_EUSB_PHY_INIT_CFG(o, b, v)	\
+{				\
+	.off = o,		\
+	.mask = b,		\
+	.val = v,		\
+}
+
+struct m31_phy_tbl_entry {
+	u32 off;
+	u32 mask;
+	u32 val;
+};
+
+struct m31_eusb2_priv_data {
+	const struct m31_phy_tbl_entry	*setup_seq;
+	unsigned int			setup_seq_nregs;
+	const struct m31_phy_tbl_entry	*override_seq;
+	unsigned int			override_seq_nregs;
+	const struct m31_phy_tbl_entry	*reset_seq;
+	unsigned int			reset_seq_nregs;
+	unsigned int			fsel;
+};
+
+static const struct m31_phy_tbl_entry m31_eusb2_setup_tbl[] = {
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG0, UTMI_PHY_CMN_CTRL_OVERRIDE_EN, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_UTMI_CTRL5, POR, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG1, PLL_EN, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_FSEL_SEL, FSEL_SEL, 1),
+};
+
+static const struct m31_phy_tbl_entry m31_eusb_phy_override_tbl[] = {
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_XCFGI_39_32, HSTX_PE, 0),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_XCFGI_71_64, HSTX_SWING, 7),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_XCFGI_31_24, HSTX_SLEW, 0),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_XCFGI_7_0, PLL_LOCK_TIME, 0),
+};
+
+static const struct m31_phy_tbl_entry m31_eusb_phy_reset_tbl[] = {
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL2, USB2_SUSPEND_N_SEL, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL2, USB2_SUSPEND_N, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_UTMI_CTRL0, SLEEPM, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL_COMMON0, SIDDQ_SEL, 1),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL_COMMON0, SIDDQ, 0),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_UTMI_CTRL5, POR, 0),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_HS_PHY_CTRL2, USB2_SUSPEND_N_SEL, 0),
+	M31_EUSB_PHY_INIT_CFG(USB_PHY_CFG0, UTMI_PHY_CMN_CTRL_OVERRIDE_EN, 0),
+};
+
+static const struct regulator_bulk_data m31_eusb_phy_vregs[] = {
+	{ .supply = "vdd" },
+	{ .supply = "vdda12" },
+};
+
+#define M31_EUSB_NUM_VREGS		ARRAY_SIZE(m31_eusb_phy_vregs)
+
+struct m31eusb2_phy {
+	struct phy			 *phy;
+	void __iomem			 *base;
+	const struct m31_eusb2_priv_data *data;
+	enum phy_mode			 mode;
+
+	struct regulator_bulk_data	 *vregs;
+	struct clk			 *clk;
+	struct reset_control		 *reset;
+
+	struct phy			 *repeater;
+};
+
+static int m31eusb2_phy_write_readback(void __iomem *base, u32 offset,
+				       const u32 mask, u32 val)
+{
+	u32 write_val;
+	u32 tmp;
+
+	tmp = readl(base + offset);
+	tmp &= ~mask;
+	write_val = tmp | val;
+
+	writel(write_val, base + offset);
+
+	tmp = readl(base + offset);
+	tmp &= mask;
+
+	if (tmp != val) {
+		pr_err("write: %x to offset: %x FAILED\n", val, offset);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int m31eusb2_phy_write_sequence(struct m31eusb2_phy *phy,
+				       const struct m31_phy_tbl_entry *tbl,
+				       int num)
+{
+	int i;
+	int ret;
+
+	for (i = 0 ; i < num; i++, tbl++) {
+		dev_dbg(&phy->phy->dev, "Offset:%x BitMask:%x Value:%x",
+			tbl->off, tbl->mask, tbl->val);
+
+		ret = m31eusb2_phy_write_readback(phy->base,
+						  tbl->off, tbl->mask,
+						  tbl->val << __ffs(tbl->mask));
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int m31eusb2_phy_set_mode(struct phy *uphy, enum phy_mode mode, int submode)
+{
+	struct m31eusb2_phy *phy = phy_get_drvdata(uphy);
+
+	phy->mode = mode;
+
+	return phy_set_mode_ext(phy->repeater, mode, submode);
+}
+
+static int m31eusb2_phy_init(struct phy *uphy)
+{
+	struct m31eusb2_phy *phy = phy_get_drvdata(uphy);
+	const struct m31_eusb2_priv_data *data = phy->data;
+	int ret;
+
+	ret = regulator_bulk_enable(M31_EUSB_NUM_VREGS, phy->vregs);
+	if (ret) {
+		dev_err(&uphy->dev, "failed to enable regulator, %d\n", ret);
+		return ret;
+	}
+
+	ret = phy_init(phy->repeater);
+	if (ret) {
+		dev_err(&uphy->dev, "repeater init failed. %d\n", ret);
+		goto disable_vreg;
+	}
+
+	ret = clk_prepare_enable(phy->clk);
+	if (ret) {
+		dev_err(&uphy->dev, "failed to enable cfg ahb clock, %d\n", ret);
+		goto disable_repeater;
+	}
+
+	/* Perform phy reset */
+	reset_control_assert(phy->reset);
+	udelay(5);
+	reset_control_deassert(phy->reset);
+
+	m31eusb2_phy_write_sequence(phy, data->setup_seq, data->setup_seq_nregs);
+	m31eusb2_phy_write_readback(phy->base,
+				    USB_PHY_HS_PHY_CTRL_COMMON0, FSEL,
+				    FIELD_PREP(FSEL, data->fsel));
+	m31eusb2_phy_write_sequence(phy, data->override_seq, data->override_seq_nregs);
+	m31eusb2_phy_write_sequence(phy, data->reset_seq, data->reset_seq_nregs);
+
+	return 0;
+
+disable_repeater:
+	phy_exit(phy->repeater);
+disable_vreg:
+	regulator_bulk_disable(M31_EUSB_NUM_VREGS, phy->vregs);
+
+	return 0;
+}
+
+static int m31eusb2_phy_exit(struct phy *uphy)
+{
+	struct m31eusb2_phy *phy = phy_get_drvdata(uphy);
+
+	clk_disable_unprepare(phy->clk);
+	regulator_bulk_disable(M31_EUSB_NUM_VREGS, phy->vregs);
+	phy_exit(phy->repeater);
+
+	return 0;
+}
+
+static const struct phy_ops m31eusb2_phy_gen_ops = {
+	.init		= m31eusb2_phy_init,
+	.exit		= m31eusb2_phy_exit,
+	.set_mode	= m31eusb2_phy_set_mode,
+	.owner		= THIS_MODULE,
+};
+
+static int m31eusb2_phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	const struct m31_eusb2_priv_data *data;
+	struct device *dev = &pdev->dev;
+	struct m31eusb2_phy *phy;
+	int ret;
+
+	phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	data = device_get_match_data(dev);
+	if (IS_ERR(data))
+		return -EINVAL;
+	phy->data = data;
+
+	phy->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(phy->base))
+		return PTR_ERR(phy->base);
+
+	phy->reset = devm_reset_control_get_exclusive(dev, NULL);
+	if (IS_ERR(phy->reset))
+		return PTR_ERR(phy->reset);
+
+	phy->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(phy->clk))
+		return dev_err_probe(dev, PTR_ERR(phy->clk),
+				     "failed to get clk\n");
+
+	phy->phy = devm_phy_create(dev, NULL, &m31eusb2_phy_gen_ops);
+	if (IS_ERR(phy->phy))
+		return dev_err_probe(dev, PTR_ERR(phy->phy),
+				     "failed to create phy\n");
+
+	ret = devm_regulator_bulk_get_const(dev, M31_EUSB_NUM_VREGS,
+					    m31_eusb_phy_vregs, &phy->vregs);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				"failed to get regulator supplies\n");
+
+	phy_set_drvdata(phy->phy, phy);
+
+	phy->repeater = devm_of_phy_get_by_index(dev, dev->of_node, 0);
+	if (IS_ERR(phy->repeater))
+		return dev_err_probe(dev, PTR_ERR(phy->repeater),
+				     "failed to get repeater\n");
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (!IS_ERR(phy_provider))
+		dev_info(dev, "Registered M31 USB phy\n");
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct m31_eusb2_priv_data m31_eusb_v1_data = {
+	.setup_seq = m31_eusb2_setup_tbl,
+	.setup_seq_nregs = ARRAY_SIZE(m31_eusb2_setup_tbl),
+	.override_seq = m31_eusb_phy_override_tbl,
+	.override_seq_nregs = ARRAY_SIZE(m31_eusb_phy_override_tbl),
+	.reset_seq = m31_eusb_phy_reset_tbl,
+	.reset_seq_nregs = ARRAY_SIZE(m31_eusb_phy_reset_tbl),
+	.fsel = FSEL_38_4_MHZ_VAL,
+};
+
+static const struct of_device_id m31eusb2_phy_id_table[] = {
+	{ .compatible = "qcom,sm8750-m31-eusb2-phy", .data = &m31_eusb_v1_data },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, m31eusb2_phy_id_table);
+
+static struct platform_driver m31eusb2_phy_driver = {
+	.probe = m31eusb2_phy_probe,
+	.driver = {
+		.name = "qcom-m31eusb2-phy",
+		.of_match_table = m31eusb2_phy_id_table,
+	},
+};
+
+module_platform_driver(m31eusb2_phy_driver);
+
+MODULE_AUTHOR("Wesley Cheng <[email protected]>");
+MODULE_DESCRIPTION("eUSB2 Qualcomm M31 HSPHY driver");
+MODULE_LICENSE("GPL");