xref: /openbmc/linux/drivers/phy/phy-lgm-usb.c (revision cbed624f)
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 
37 static const char *const PHY_RESETS[] = { "phy31", "phy", };
38 static const char *const CTL_RESETS[] = { "apb", "ctrl", };
39 
40 struct 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 
get_flipped(struct tca_apb * ta,bool * flipped)51 static 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 
phy_init(struct usb_phy * phy)68 static 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 
phy_shutdown(struct usb_phy * phy)99 static 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 
phy_set_vbus(struct usb_phy * phy,int on)118 static 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 
tca_work(struct work_struct * work)138 static 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 
id_notifier(struct notifier_block * nb,unsigned long event,void * ptr)172 static 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 
vbus_notifier(struct notifier_block * nb,unsigned long evnt,void * ptr)182 static int vbus_notifier(struct notifier_block *nb, unsigned long evnt, void *ptr)
183 {
184 	return NOTIFY_DONE;
185 }
186 
phy_probe(struct platform_device * pdev)187 static 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 
phy_remove(struct platform_device * pdev)255 static 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 
262 static const struct of_device_id intel_usb_phy_dt_ids[] = {
263 	{ .compatible = "intel,lgm-usb-phy" },
264 	{ }
265 };
266 MODULE_DEVICE_TABLE(of, intel_usb_phy_dt_ids);
267 
268 static 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 
277 module_platform_driver(lgm_phy_driver);
278 
279 MODULE_DESCRIPTION("Intel LGM USB PHY driver");
280 MODULE_AUTHOR("Li Yin <yin1.li@intel.com>");
281 MODULE_AUTHOR("Vadivel Murugan R <vadivel.muruganx.ramuthevar@linux.intel.com>");
282 MODULE_LICENSE("GPL v2");
283