reset-rzv2h-usb2phy.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Renesas RZ/V2H(P) USB2PHY Port reset control driver
  4 *
  5 * Copyright (C) 2025 Renesas Electronics Corporation
  6 */
  7
  8#include <linux/cleanup.h>
  9#include <linux/delay.h>
 10#include <linux/io.h>
 11#include <linux/module.h>
 12#include <linux/of.h>
 13#include <linux/platform_device.h>
 14#include <linux/pm_runtime.h>
 15#include <linux/reset.h>
 16#include <linux/reset-controller.h>
 17
 18struct rzv2h_usb2phy_regval {
 19	u16 reg;
 20	u16 val;
 21};
 22
 23struct rzv2h_usb2phy_reset_of_data {
 24	const struct rzv2h_usb2phy_regval *init_vals;
 25	unsigned int init_val_count;
 26
 27	u16 reset_reg;
 28	u16 reset_assert_val;
 29	u16 reset_deassert_val;
 30	u16 reset_status_bits;
 31	u16 reset_release_val;
 32
 33	u16 reset2_reg;
 34	u16 reset2_acquire_val;
 35	u16 reset2_release_val;
 36};
 37
 38struct rzv2h_usb2phy_reset_priv {
 39	const struct rzv2h_usb2phy_reset_of_data *data;
 40	void __iomem *base;
 41	struct device *dev;
 42	struct reset_controller_dev rcdev;
 43	spinlock_t lock; /* protects register accesses */
 44};
 45
 46static inline struct rzv2h_usb2phy_reset_priv
 47*rzv2h_usbphy_rcdev_to_priv(struct reset_controller_dev *rcdev)
 48{
 49	return container_of(rcdev, struct rzv2h_usb2phy_reset_priv, rcdev);
 50}
 51
 52/* This function must be called only after pm_runtime_resume_and_get() has been called */
 53static void rzv2h_usbphy_assert_helper(struct rzv2h_usb2phy_reset_priv *priv)
 54{
 55	const struct rzv2h_usb2phy_reset_of_data *data = priv->data;
 56
 57	scoped_guard(spinlock, &priv->lock) {
 58		writel(data->reset2_acquire_val, priv->base + data->reset2_reg);
 59		writel(data->reset_assert_val, priv->base + data->reset_reg);
 60	}
 61
 62	usleep_range(11, 20);
 63}
 64
 65static int rzv2h_usbphy_reset_assert(struct reset_controller_dev *rcdev,
 66				     unsigned long id)
 67{
 68	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
 69	struct device *dev = priv->dev;
 70	int ret;
 71
 72	ret = pm_runtime_resume_and_get(dev);
 73	if (ret) {
 74		dev_err(dev, "pm_runtime_resume_and_get failed\n");
 75		return ret;
 76	}
 77
 78	rzv2h_usbphy_assert_helper(priv);
 79
 80	pm_runtime_put(dev);
 81
 82	return 0;
 83}
 84
 85static int rzv2h_usbphy_reset_deassert(struct reset_controller_dev *rcdev,
 86				       unsigned long id)
 87{
 88	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
 89	const struct rzv2h_usb2phy_reset_of_data *data = priv->data;
 90	struct device *dev = priv->dev;
 91	int ret;
 92
 93	ret = pm_runtime_resume_and_get(dev);
 94	if (ret) {
 95		dev_err(dev, "pm_runtime_resume_and_get failed\n");
 96		return ret;
 97	}
 98
 99	scoped_guard(spinlock, &priv->lock) {
100		writel(data->reset_deassert_val, priv->base + data->reset_reg);
101		writel(data->reset2_release_val, priv->base + data->reset2_reg);
102		writel(data->reset_release_val, priv->base + data->reset_reg);
103	}
104
105	pm_runtime_put(dev);
106
107	return 0;
108}
109
110static int rzv2h_usbphy_reset_status(struct reset_controller_dev *rcdev,
111				     unsigned long id)
112{
113	struct rzv2h_usb2phy_reset_priv *priv = rzv2h_usbphy_rcdev_to_priv(rcdev);
114	struct device *dev = priv->dev;
115	int ret;
116	u32 reg;
117
118	ret = pm_runtime_resume_and_get(dev);
119	if (ret) {
120		dev_err(dev, "pm_runtime_resume_and_get failed\n");
121		return ret;
122	}
123
124	reg = readl(priv->base + priv->data->reset_reg);
125
126	pm_runtime_put(dev);
127
128	return (reg & priv->data->reset_status_bits) == priv->data->reset_status_bits;
129}
130
131static const struct reset_control_ops rzv2h_usbphy_reset_ops = {
132	.assert = rzv2h_usbphy_reset_assert,
133	.deassert = rzv2h_usbphy_reset_deassert,
134	.status = rzv2h_usbphy_reset_status,
135};
136
137static int rzv2h_usb2phy_reset_of_xlate(struct reset_controller_dev *rcdev,
138					const struct of_phandle_args *reset_spec)
139{
140	/* No special handling needed, we have only one reset line per device */
141	return 0;
142}
143
144static int rzv2h_usb2phy_reset_probe(struct platform_device *pdev)
145{
146	const struct rzv2h_usb2phy_reset_of_data *data;
147	struct rzv2h_usb2phy_reset_priv *priv;
148	struct device *dev = &pdev->dev;
149	struct reset_control *rstc;
150	int error;
151
152	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
153	if (!priv)
154		return -ENOMEM;
155
156	data = of_device_get_match_data(dev);
157	priv->data = data;
158	priv->dev = dev;
159	priv->base = devm_platform_ioremap_resource(pdev, 0);
160	if (IS_ERR(priv->base))
161		return PTR_ERR(priv->base);
162
163	rstc = devm_reset_control_get_shared_deasserted(dev, NULL);
164	if (IS_ERR(rstc))
165		return dev_err_probe(dev, PTR_ERR(rstc),
166				     "failed to get deasserted reset\n");
167
168	spin_lock_init(&priv->lock);
169
170	error = devm_pm_runtime_enable(dev);
171	if (error)
172		return dev_err_probe(dev, error, "Failed to enable pm_runtime\n");
173
174	error = pm_runtime_resume_and_get(dev);
175	if (error)
176		return dev_err_probe(dev, error, "pm_runtime_resume_and_get failed\n");
177
178	for (unsigned int i = 0; i < data->init_val_count; i++)
179		writel(data->init_vals[i].val, priv->base + data->init_vals[i].reg);
180
181	/* keep usb2phy in asserted state */
182	rzv2h_usbphy_assert_helper(priv);
183
184	pm_runtime_put(dev);
185
186	priv->rcdev.ops = &rzv2h_usbphy_reset_ops;
187	priv->rcdev.of_reset_n_cells = 0;
188	priv->rcdev.nr_resets = 1;
189	priv->rcdev.of_xlate = rzv2h_usb2phy_reset_of_xlate;
190	priv->rcdev.of_node = dev->of_node;
191	priv->rcdev.dev = dev;
192
193	return devm_reset_controller_register(dev, &priv->rcdev);
194}
195
196/*
197 * initialization values required to prepare the PHY to receive
198 * assert and deassert requests.
199 */
200static const struct rzv2h_usb2phy_regval rzv2h_init_vals[] = {
201	{ .reg = 0xc10, .val = 0x67c },
202	{ .reg = 0xc14, .val = 0x1f },
203	{ .reg = 0x600, .val = 0x909 },
204};
205
206static const struct rzv2h_usb2phy_reset_of_data rzv2h_reset_of_data = {
207	.init_vals = rzv2h_init_vals,
208	.init_val_count = ARRAY_SIZE(rzv2h_init_vals),
209	.reset_reg = 0,
210	.reset_assert_val = 0x206,
211	.reset_status_bits = BIT(2),
212	.reset_deassert_val = 0x200,
213	.reset_release_val = 0x0,
214	.reset2_reg = 0xb04,
215	.reset2_acquire_val = 0x303,
216	.reset2_release_val = 0x3,
217};
218
219static const struct of_device_id rzv2h_usb2phy_reset_of_match[] = {
220	{ .compatible = "renesas,r9a09g057-usb2phy-reset", .data = &rzv2h_reset_of_data },
221	{ /* Sentinel */ }
222};
223MODULE_DEVICE_TABLE(of, rzv2h_usb2phy_reset_of_match);
224
225static struct platform_driver rzv2h_usb2phy_reset_driver = {
226	.driver = {
227		.name		= "rzv2h_usb2phy_reset",
228		.of_match_table	= rzv2h_usb2phy_reset_of_match,
229	},
230	.probe = rzv2h_usb2phy_reset_probe,
231};
232module_platform_driver(rzv2h_usb2phy_reset_driver);
233
234MODULE_LICENSE("GPL");
235MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>");
236MODULE_DESCRIPTION("Renesas RZ/V2H(P) USB2PHY Control");