[PATCH 2/2] reset: Add USB2PHY control driver for Renesas RZ/V2H(P)

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

Add support for the USB2PHY control driver on the Renesas RZ/V2H(P) SoC.
Make the driver handle reset and power-down operations for the USB2PHY.

Pass OF data to support future SoCs with similar USB2PHY hardware but
different register configurations. Define device-specific initialization
values and control register settings in OF data to ensure flexibility
for upcoming SoCs.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
---
 drivers/reset/Kconfig                    |   7 +
 drivers/reset/Makefile                   |   1 +
 drivers/reset/reset-rzv2h-usb2phy-ctrl.c | 220 +++++++++++++++++++++++
 3 files changed, 228 insertions(+)
 create mode 100644 drivers/reset/reset-rzv2h-usb2phy-ctrl.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 5b3abb6db248..bac08dae8905 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -218,6 +218,13 @@ config RESET_RZG2L_USBPHY_CTRL
 	  Support for USBPHY Control found on RZ/G2L family. It mainly
 	  controls reset and power down of the USB/PHY.
 
+config RESET_RZV2H_USB2PHY_CTRL
+	tristate "Renesas RZ/V2H(P) (and similar SoCs) USB2PHY control driver"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	help
+	  Support for USB2PHY Control found on the RZ/V2H(P) SoC (and similar SoCs).
+	  It mainly controls reset and power down of the USB2 PHY.
+
 config RESET_SCMI
 	tristate "Reset driver controlled via ARM SCMI interface"
 	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 677c4d1e2632..3cb3df018cf8 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
 obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o
 obj-$(CONFIG_RESET_RASPBERRYPI) += reset-raspberrypi.o
 obj-$(CONFIG_RESET_RZG2L_USBPHY_CTRL) += reset-rzg2l-usbphy-ctrl.o
+obj-$(CONFIG_RESET_RZV2H_USB2PHY_CTRL) += reset-rzv2h-usb2phy-ctrl.o
 obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
 obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
diff --git a/drivers/reset/reset-rzv2h-usb2phy-ctrl.c b/drivers/reset/reset-rzv2h-usb2phy-ctrl.c
new file mode 100644
index 000000000000..5b6ad5f6dc82
--- /dev/null
+++ b/drivers/reset/reset-rzv2h-usb2phy-ctrl.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/V2H(P) USB2PHY control driver
+ *
+ * Copyright (C) 2025 Renesas Electronics Corporation
+ */
+
+#include <linux/cleanup.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/reset-controller.h>
+
+struct rzv2h_usb2phy_regval {
+	u16 reg;
+	u16 val;
+};
+
+struct rzv2h_usb2phy_data {
+	const struct rzv2h_usb2phy_regval *init_vals;
+	unsigned int init_val_count;
+
+	u16 ctrl_reg;
+	u16 ctrl_assert_val;
+	u16 ctrl_deassert_val;
+	u16 ctrl_status_bits;
+	u16 ctrl_release_val;
+
+	u16 ctrl2_reg;
+	u16 ctrl2_release_val;
+};
+
+struct rzv2h_usb2phy_ctrl_priv {
+	const struct rzv2h_usb2phy_data *data;
+	void __iomem *base;
+	struct device *dev;
+	struct reset_controller_dev rcdev;
+	spinlock_t lock;
+};
+
+#define rcdev_to_priv(x) container_of(x, struct rzv2h_usb2phy_ctrl_priv, rcdev)
+
+static int rzv2h_usbphy_ctrl_assert(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct rzv2h_usb2phy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	const struct rzv2h_usb2phy_data *data = priv->data;
+	struct device *dev = priv->dev;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret) {
+		dev_err(dev, "pm_runtime_resume_and_get failed\n");
+		return ret;
+	}
+	scoped_guard(spinlock, &priv->lock)
+		writel(data->ctrl_assert_val, priv->base + data->ctrl_reg);
+
+	/* The reset line needs to be asserted for more than 10 microseconds. */
+	udelay(11);
+	pm_runtime_put(dev);
+
+	return 0;
+}
+
+static int rzv2h_usbphy_ctrl_deassert(struct reset_controller_dev *rcdev,
+				      unsigned long id)
+{
+	struct rzv2h_usb2phy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	const struct rzv2h_usb2phy_data *data = priv->data;
+	struct device *dev = priv->dev;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret) {
+		dev_err(dev, "pm_runtime_resume_and_get failed\n");
+		return ret;
+	}
+
+	scoped_guard(spinlock, &priv->lock) {
+		writel(data->ctrl_deassert_val, priv->base + data->ctrl_reg);
+		writel(data->ctrl2_release_val, priv->base + data->ctrl2_reg);
+		writel(data->ctrl_release_val, priv->base + data->ctrl_reg);
+	}
+
+	pm_runtime_put(dev);
+
+	return 0;
+}
+
+static int rzv2h_usbphy_ctrl_status(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct rzv2h_usb2phy_ctrl_priv *priv = rcdev_to_priv(rcdev);
+	struct device *dev = priv->dev;
+	int ret;
+	u32 reg;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret) {
+		dev_err(dev, "pm_runtime_resume_and_get failed\n");
+		return ret;
+	}
+
+	scoped_guard(spinlock, &priv->lock)
+		reg = readl(priv->base + priv->data->ctrl_reg);
+
+	pm_runtime_put(dev);
+
+	return (reg & priv->data->ctrl_status_bits) == priv->data->ctrl_status_bits;
+}
+
+static const struct reset_control_ops rzv2h_usbphy_ctrl_reset_ops = {
+	.assert = rzv2h_usbphy_ctrl_assert,
+	.deassert = rzv2h_usbphy_ctrl_deassert,
+	.status = rzv2h_usbphy_ctrl_status,
+};
+
+static int rzv2h_reset_of_xlate(struct reset_controller_dev *rcdev,
+				const struct of_phandle_args *reset_spec)
+{
+	/* No special handling needed, we have only one reset line per device */
+	return 0;
+}
+
+static int rzv2h_usb2phy_ctrl_probe(struct platform_device *pdev)
+{
+	const struct rzv2h_usb2phy_data *data;
+	struct rzv2h_usb2phy_ctrl_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct reset_control *rstc;
+	int error;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	data = of_device_get_match_data(dev);
+	if (!data)
+		return dev_err_probe(dev, -ENODEV,
+				     "failed to match device\n");
+
+	priv->data = data;
+	priv->dev = dev;
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	rstc = devm_reset_control_get_shared_deasserted(dev, NULL);
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc),
+				     "failed to get deasserted reset\n");
+
+	spin_lock_init(&priv->lock);
+	dev_set_drvdata(dev, priv);
+
+	error = devm_pm_runtime_enable(dev);
+	if (error)
+		return dev_err_probe(dev, error, "Failed to enable pm_runtime\n");
+
+	error = pm_runtime_resume_and_get(dev);
+	if (error)
+		return dev_err_probe(dev, error, "pm_runtime_resume_and_get failed\n");
+
+	for (unsigned int i = 0; i < data->init_val_count; i++)
+		writel(data->init_vals[i].val, priv->base + data->init_vals[i].reg);
+
+	pm_runtime_put(dev);
+
+	priv->rcdev.ops = &rzv2h_usbphy_ctrl_reset_ops;
+	priv->rcdev.of_reset_n_cells = 0;
+	priv->rcdev.nr_resets = 1;
+	priv->rcdev.of_xlate = rzv2h_reset_of_xlate;
+	priv->rcdev.of_node = dev->of_node;
+	priv->rcdev.dev = dev;
+
+	return devm_reset_controller_register(dev, &priv->rcdev);
+}
+
+static const struct rzv2h_usb2phy_regval rzv2h_init_vals[] = {
+	{ .reg = 0xb04, .val = 0x303 },
+	{ .reg = 0xc10, .val = 0x67c },
+	{ .reg = 0xc14, .val = 0x1f },
+	{ .reg = 0x600, .val = 0x909 },
+};
+
+static const struct rzv2h_usb2phy_data rzv2h_of_data = {
+	.init_vals = rzv2h_init_vals,
+	.init_val_count = ARRAY_SIZE(rzv2h_init_vals),
+	.ctrl_reg = 0,
+	.ctrl_assert_val = 0x206,
+	.ctrl_status_bits = 0x204,
+	.ctrl_deassert_val = 0x200,
+	.ctrl_release_val = 0x0,
+	.ctrl2_reg = 0xb04,
+	.ctrl2_release_val = 0x3,
+};
+
+static const struct of_device_id rzv2h_usb2phy_ctrl_match_table[] = {
+	{ .compatible = "renesas,r9a09g057-usb2phy-ctrl", .data = &rzv2h_of_data },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzv2h_usb2phy_ctrl_match_table);
+
+static struct platform_driver rzv2h_usb2phy_ctrl_driver = {
+	.driver = {
+		.name		= "rzv2h_usb2phy_ctrl",
+		.of_match_table	= rzv2h_usb2phy_ctrl_match_table,
+	},
+	.probe = rzv2h_usb2phy_ctrl_probe,
+};
+module_platform_driver(rzv2h_usb2phy_ctrl_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Renesas RZ/V2H(P) USB2PHY Control");
-- 
2.43.0