Message-ID:
 <TYCPR01MB120934D9C83511FA61366B685C2BD2@TYCPR01MB12093.jpnprd01.prod.outlook.com>
Date: Wed, 16 Apr 2025 08:50:36 +0000
From: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
To: Prabhakar <prabhakar.csengg@...il.com>, Philipp Zabel
	<p.zabel@...gutronix.de>, Geert Uytterhoeven <geert+renesas@...der.be>, Rob
 Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor
 Dooley <conor+dt@...nel.org>, Magnus Damm <magnus.damm@...il.com>
CC: "linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Biju Das
	<biju.das.jz@...renesas.com>, Prabhakar Mahadev Lad
	<prabhakar.mahadev-lad.rj@...renesas.com>
Subject: RE: [PATCH v5 2/3] reset: Add USB2PHY port reset driver for Renesas
 RZ/V2H(P)

> From: Prabhakar <prabhakar.csengg@...il.com>
> Sent: 15 April 2025 20:52
> Subject: [PATCH v5 2/3] reset: Add USB2PHY port reset driver for Renesas RZ/V2H(P)
> 
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> Implement a USB2PHY port reset driver for the Renesas RZ/V2H(P) SoC.
> Enable control of USB2.0 PHY reset and power-down operations, including
> assert and deassert functionalities for the PHY.
> 
> Leverage device tree (OF) data to support future SoCs with similar USB2PHY
> hardware but varying register configurations. Define initialization values
> and control register settings to ensure flexibility for upcoming platforms.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> Reviewed-by: Biju Das <biju.das.jz@...renesas.com>

Reviewed-by: Fabrizio Castro <fabrizio.castro.jz@...esas.com>

> ---
>  drivers/reset/Kconfig               |   7 +
>  drivers/reset/Makefile              |   1 +
>  drivers/reset/reset-rzv2h-usb2phy.c | 236 ++++++++++++++++++++++++++++
>  3 files changed, 244 insertions(+)
>  create mode 100644 drivers/reset/reset-rzv2h-usb2phy.c
> 
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 11ce86c8156b..d85be5899da6 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -225,6 +225,13 @@ 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
> +	tristate "Renesas RZ/V2H(P) (and similar SoCs) USB2PHY Reset driver"
> +	depends on ARCH_RENESAS || COMPILE_TEST
> +	help
> +	  Support for USB2PHY Port reset Control found on the RZ/V2H(P) SoC
> +	  (and similar SoCs).
> +
>  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 6322a191e2a8..91e6348e3351 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -31,6 +31,7 @@ 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-$(CONFIG_RESET_RZV2H_USB2PHY) += reset-rzv2h-usb2phy.o
>  obj-$(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.c b/drivers/reset/reset-rzv2h-usb2phy.c
> new file mode 100644
> index 000000000000..ae643575b067
> --- /dev/null
> +++ b/drivers/reset/reset-rzv2h-usb2phy.c
> @@ -0,0 +1,236 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/V2H(P) USB2PHY Port reset 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_reset_of_data {
> +	const struct rzv2h_usb2phy_regval *init_vals;
> +	unsigned int init_val_count;
> +
> +	u16 reset_reg;
> +	u16 reset_assert_val;
> +	u16 reset_deassert_val;
> +	u16 reset_status_bits;
> +	u16 reset_release_val;
> +
> +	u16 reset2_reg;
> +	u16 reset2_acquire_val;
> +	u16 reset2_release_val;
> +};
> +
> +struct rzv2h_usb2phy_reset_priv {
> +	const struct rzv2h_usb2phy_reset_of_data *data;
> +	void __iomem *base;
> +	struct device *dev;
> +	struct reset_controller_dev rcdev;
> +	spinlock_t lock; /* protects register accesses */
> +};
> +
> +static inline struct rzv2h_usb2phy_reset_priv
> +*rzv2h_usbphy_rcdev_to_priv(struct reset_controller_dev *rcdev)
> +{
> +	return container_of(rcdev, struct rzv2h_usb2phy_reset_priv, rcdev);
> +}
> +
> +/* This function must be called only after pm_runtime_resume_and_get() has been called */
> +static void rzv2h_usbphy_assert_helper(struct rzv2h_usb2phy_reset_priv *priv)
> +{
> +	const struct rzv2h_usb2phy_reset_of_data *data = priv->data;
> +
> +	scoped_guard(spinlock, &priv->lock) {
> +		writel(data->reset2_acquire_val, priv->base + data->reset2_reg);
> +		writel(data->reset_assert_val, priv->base + data->reset_reg);
> +	}
> +
> +	usleep_range(11, 20);
> +}
> +
> +static int rzv2h_usbphy_reset_assert(struct reset_controller_dev *rcdev,
> +				     unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
> +	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;
> +	}
> +
> +	rzv2h_usbphy_assert_helper(priv);
> +
> +	pm_runtime_put(dev);
> +
> +	return 0;
> +}
> +
> +static int rzv2h_usbphy_reset_deassert(struct reset_controller_dev *rcdev,
> +				       unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
> +	const struct rzv2h_usb2phy_reset_of_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->reset_deassert_val, priv->base + data->reset_reg);
> +		writel(data->reset2_release_val, priv->base + data->reset2_reg);
> +		writel(data->reset_release_val, priv->base + data->reset_reg);
> +	}
> +
> +	pm_runtime_put(dev);
> +
> +	return 0;
> +}
> +
> +static int rzv2h_usbphy_reset_status(struct reset_controller_dev *rcdev,
> +				     unsigned long id)
> +{
> +	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_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;
> +	}
> +
> +	reg = readl(priv->base + priv->data->reset_reg);
> +
> +	pm_runtime_put(dev);
> +
> +	return (reg & priv->data->reset_status_bits) == priv->data->reset_status_bits;
> +}
> +
> +static const struct reset_control_ops rzv2h_usbphy_reset_ops = {
> +	.assert = rzv2h_usbphy_reset_assert,
> +	.deassert = rzv2h_usbphy_reset_deassert,
> +	.status = rzv2h_usbphy_reset_status,
> +};
> +
> +static int rzv2h_usb2phy_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_reset_probe(struct platform_device *pdev)
> +{
> +	const struct rzv2h_usb2phy_reset_of_data *data;
> +	struct rzv2h_usb2phy_reset_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);
> +	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);
> +
> +	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);
> +
> +	/* keep usb2phy in asserted state */
> +	rzv2h_usbphy_assert_helper(priv);
> +
> +	pm_runtime_put(dev);
> +
> +	priv->rcdev.ops = &rzv2h_usbphy_reset_ops;
> +	priv->rcdev.of_reset_n_cells = 0;
> +	priv->rcdev.nr_resets = 1;
> +	priv->rcdev.of_xlate = rzv2h_usb2phy_reset_of_xlate;
> +	priv->rcdev.of_node = dev->of_node;
> +	priv->rcdev.dev = dev;
> +
> +	return devm_reset_controller_register(dev, &priv->rcdev);
> +}
> +
> +/*
> + * initialization values required to prepare the PHY to receive
> + * assert and deassert requests.
> + */
> +static const struct rzv2h_usb2phy_regval rzv2h_init_vals[] = {
> +	{ .reg = 0xc10, .val = 0x67c },
> +	{ .reg = 0xc14, .val = 0x1f },
> +	{ .reg = 0x600, .val = 0x909 },
> +};
> +
> +static const struct rzv2h_usb2phy_reset_of_data rzv2h_reset_of_data = {
> +	.init_vals = rzv2h_init_vals,
> +	.init_val_count = ARRAY_SIZE(rzv2h_init_vals),
> +	.reset_reg = 0,
> +	.reset_assert_val = 0x206,
> +	.reset_status_bits = BIT(2),
> +	.reset_deassert_val = 0x200,
> +	.reset_release_val = 0x0,
> +	.reset2_reg = 0xb04,
> +	.reset2_acquire_val = 0x303,
> +	.reset2_release_val = 0x3,
> +};
> +
> +static const struct of_device_id rzv2h_usb2phy_reset_of_match[] = {
> +	{ .compatible = "renesas,r9a09g057-usb2phy-reset", .data = &rzv2h_reset_of_data },
> +	{ /* Sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, rzv2h_usb2phy_reset_of_match);
> +
> +static struct platform_driver rzv2h_usb2phy_reset_driver = {
> +	.driver = {
> +		.name		= "rzv2h_usb2phy_reset",
> +		.of_match_table	= rzv2h_usb2phy_reset_of_match,
> +	},
> +	.probe = rzv2h_usb2phy_reset_probe,
> +};
> +module_platform_driver(rzv2h_usb2phy_reset_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>");
> +MODULE_DESCRIPTION("Renesas RZ/V2H(P) USB2PHY Control");
> --
> 2.49.0

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