1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Intel LGM USB PHY driver
  4 *
  5 * Copyright (C) 2020 Intel Corporation.
  6 */
  7
  8#include <linux/bitfield.h>
  9#include <linux/delay.h>
 10#include <linux/iopoll.h>
 11#include <linux/module.h>
 12#include <linux/of.h>
 13#include <linux/platform_device.h>
 14#include <linux/regulator/consumer.h>
 15#include <linux/reset.h>
 16#include <linux/usb/phy.h>
 17#include <linux/workqueue.h>
 18
 19#define CTRL1_OFFSET		0x14
 20#define SRAM_EXT_LD_DONE	BIT(25)
 21#define SRAM_INIT_DONE		BIT(26)
 22
 23#define TCPC_OFFSET		0x1014
 24#define TCPC_MUX_CTL		GENMASK(1, 0)
 25#define MUX_NC			0
 26#define MUX_USB			1
 27#define MUX_DP			2
 28#define MUX_USBDP		3
 29#define TCPC_FLIPPED		BIT(2)
 30#define TCPC_LOW_POWER_EN	BIT(3)
 31#define TCPC_VALID		BIT(4)
 32#define TCPC_CONN		\
 33	(TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_USB))
 34#define TCPC_DISCONN		\
 35	(TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_NC) | TCPC_LOW_POWER_EN)
 36
 37static const char *const PHY_RESETS[] = { "phy31", "phy", };
 38static const char *const CTL_RESETS[] = { "apb", "ctrl", };
 39
 40struct tca_apb {
 41	struct reset_control *resets[ARRAY_SIZE(PHY_RESETS)];
 42	struct regulator *vbus;
 43	struct work_struct wk;
 44	struct usb_phy phy;
 45
 46	bool regulator_enabled;
 47	bool phy_initialized;
 48	bool connected;
 49};
 50
 51static int get_flipped(struct tca_apb *ta, bool *flipped)
 52{
 53	union extcon_property_value property;
 54	int ret;
 55
 56	ret = extcon_get_property(ta->phy.edev, EXTCON_USB_HOST,
 57				  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
 58	if (ret) {
 59		dev_err(ta->phy.dev, "no polarity property from extcon\n");
 60		return ret;
 61	}
 62
 63	*flipped = property.intval;
 64
 65	return 0;
 66}
 67
 68static int phy_init(struct usb_phy *phy)
 69{
 70	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
 71	void __iomem *ctrl1 = phy->io_priv + CTRL1_OFFSET;
 72	int val, ret, i;
 73
 74	if (ta->phy_initialized)
 75		return 0;
 76
 77	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
 78		reset_control_deassert(ta->resets[i]);
 79
 80	ret = readl_poll_timeout(ctrl1, val, val & SRAM_INIT_DONE, 10, 10 * 1000);
 81	if (ret) {
 82		dev_err(ta->phy.dev, "SRAM init failed, 0x%x\n", val);
 83		return ret;
 84	}
 85
 86	writel(readl(ctrl1) | SRAM_EXT_LD_DONE, ctrl1);
 87
 88	ta->phy_initialized = true;
 89	if (!ta->phy.edev) {
 90		writel(TCPC_CONN, ta->phy.io_priv + TCPC_OFFSET);
 91		return phy->set_vbus(phy, true);
 92	}
 93
 94	schedule_work(&ta->wk);
 95
 96	return ret;
 97}
 98
 99static void phy_shutdown(struct usb_phy *phy)
100{
101	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
102	int i;
103
104	if (!ta->phy_initialized)
105		return;
106
107	ta->phy_initialized = false;
108	flush_work(&ta->wk);
109	ta->phy.set_vbus(&ta->phy, false);
110
111	ta->connected = false;
112	writel(TCPC_DISCONN, ta->phy.io_priv + TCPC_OFFSET);
113
114	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
115		reset_control_assert(ta->resets[i]);
116}
117
118static int phy_set_vbus(struct usb_phy *phy, int on)
119{
120	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
121	int ret;
122
123	if (!!on == ta->regulator_enabled)
124		return 0;
125
126	if (on)
127		ret = regulator_enable(ta->vbus);
128	else
129		ret = regulator_disable(ta->vbus);
130
131	if (!ret)
132		ta->regulator_enabled = on;
133
134	dev_dbg(ta->phy.dev, "set vbus: %d\n", on);
135	return ret;
136}
137
138static void tca_work(struct work_struct *work)
139{
140	struct tca_apb *ta = container_of(work, struct tca_apb, wk);
141	bool connected;
142	bool flipped = false;
143	u32 val;
144	int ret;
145
146	ret = get_flipped(ta, &flipped);
147	if (ret)
148		return;
149
150	connected = extcon_get_state(ta->phy.edev, EXTCON_USB_HOST);
151	if (connected == ta->connected)
152		return;
153
154	ta->connected = connected;
155	if (connected) {
156		val = TCPC_CONN;
157		if (flipped)
158			val |= TCPC_FLIPPED;
159		dev_dbg(ta->phy.dev, "connected%s\n", flipped ? " flipped" : "");
160	} else {
161		val = TCPC_DISCONN;
162		dev_dbg(ta->phy.dev, "disconnected\n");
163	}
164
165	writel(val, ta->phy.io_priv + TCPC_OFFSET);
166
167	ret = ta->phy.set_vbus(&ta->phy, connected);
168	if (ret)
169		dev_err(ta->phy.dev, "failed to set VBUS\n");
170}
171
172static int id_notifier(struct notifier_block *nb, unsigned long event, void *ptr)
173{
174	struct tca_apb *ta = container_of(nb, struct tca_apb, phy.id_nb);
175
176	if (ta->phy_initialized)
177		schedule_work(&ta->wk);
178
179	return NOTIFY_DONE;
180}
181
182static int vbus_notifier(struct notifier_block *nb, unsigned long evnt, void *ptr)
183{
184	return NOTIFY_DONE;
185}
186
187static int phy_probe(struct platform_device *pdev)
188{
189	struct reset_control *resets[ARRAY_SIZE(CTL_RESETS)];
190	struct device *dev = &pdev->dev;
191	struct usb_phy *phy;
192	struct tca_apb *ta;
193	int i;
194
195	ta = devm_kzalloc(dev, sizeof(*ta), GFP_KERNEL);
196	if (!ta)
197		return -ENOMEM;
198
199	platform_set_drvdata(pdev, ta);
200	INIT_WORK(&ta->wk, tca_work);
201
202	phy = &ta->phy;
203	phy->dev = dev;
204	phy->label = dev_name(dev);
205	phy->type = USB_PHY_TYPE_USB3;
206	phy->init = phy_init;
207	phy->shutdown = phy_shutdown;
208	phy->set_vbus = phy_set_vbus;
209	phy->id_nb.notifier_call = id_notifier;
210	phy->vbus_nb.notifier_call = vbus_notifier;
211
212	phy->io_priv = devm_platform_ioremap_resource(pdev, 0);
213	if (IS_ERR(phy->io_priv))
214		return PTR_ERR(phy->io_priv);
215
216	ta->vbus = devm_regulator_get(dev, "vbus");
217	if (IS_ERR(ta->vbus))
218		return PTR_ERR(ta->vbus);
219
220	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++) {
221		resets[i] = devm_reset_control_get_exclusive(dev, CTL_RESETS[i]);
222		if (IS_ERR(resets[i])) {
223			dev_err(dev, "%s reset not found\n", CTL_RESETS[i]);
224			return PTR_ERR(resets[i]);
225		}
226	}
227
228	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++) {
229		ta->resets[i] = devm_reset_control_get_exclusive(dev, PHY_RESETS[i]);
230		if (IS_ERR(ta->resets[i])) {
231			dev_err(dev, "%s reset not found\n", PHY_RESETS[i]);
232			return PTR_ERR(ta->resets[i]);
233		}
234	}
235
236	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
237		reset_control_assert(resets[i]);
238
239	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
240		reset_control_assert(ta->resets[i]);
241	/*
242	 * Out-of-band reset of the controller after PHY reset will cause
243	 * controller malfunctioning, so we should use in-band controller
244	 * reset only and leave the controller de-asserted here.
245	 */
246	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
247		reset_control_deassert(resets[i]);
248
249	/* Need to wait at least 20us after de-assert the controller */
250	usleep_range(20, 100);
251
252	return usb_add_phy_dev(phy);
253}
254
255static void phy_remove(struct platform_device *pdev)
256{
257	struct tca_apb *ta = platform_get_drvdata(pdev);
258
259	usb_remove_phy(&ta->phy);
260}
261
262static const struct of_device_id intel_usb_phy_dt_ids[] = {
263	{ .compatible = "intel,lgm-usb-phy" },
264	{ }
265};
266MODULE_DEVICE_TABLE(of, intel_usb_phy_dt_ids);
267
268static struct platform_driver lgm_phy_driver = {
269	.driver = {
270		.name = "lgm-usb-phy",
271		.of_match_table = intel_usb_phy_dt_ids,
272	},
273	.probe = phy_probe,
274	.remove_new = phy_remove,
275};
276
277module_platform_driver(lgm_phy_driver);
278
279MODULE_DESCRIPTION("Intel LGM USB PHY driver");
280MODULE_AUTHOR("Li Yin <yin1.li@intel.com>");
281MODULE_AUTHOR("Vadivel Murugan R <vadivel.muruganx.ramuthevar@linux.intel.com>");
282MODULE_LICENSE("GPL v2");