1// SPDX-License-Identifier: GPL-2.0
2/*
3 * mtu3_dr.c - dual role switch and host glue layer
4 *
5 * Copyright (C) 2016 MediaTek Inc.
6 *
7 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
8 */
9
10#include <linux/usb/role.h>
11
12#include "mtu3.h"
13#include "mtu3_dr.h"
14#include "mtu3_debug.h"
15
16#define USB2_PORT 2
17#define USB3_PORT 3
18
19enum mtu3_vbus_id_state {
20	MTU3_ID_FLOAT = 1,
21	MTU3_ID_GROUND,
22	MTU3_VBUS_OFF,
23	MTU3_VBUS_VALID,
24};
25
26static char *mailbox_state_string(enum mtu3_vbus_id_state state)
27{
28	switch (state) {
29	case MTU3_ID_FLOAT:
30		return "ID_FLOAT";
31	case MTU3_ID_GROUND:
32		return "ID_GROUND";
33	case MTU3_VBUS_OFF:
34		return "VBUS_OFF";
35	case MTU3_VBUS_VALID:
36		return "VBUS_VALID";
37	default:
38		return "UNKNOWN";
39	}
40}
41
42static void toggle_opstate(struct ssusb_mtk *ssusb)
43{
44	mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
45	mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
46}
47
48/* only port0 supports dual-role mode */
49static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
50	int version, bool tohost)
51{
52	void __iomem *ibase = ssusb->ippc_base;
53	u32 value;
54
55	dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
56		version, tohost ? "host" : "device");
57
58	if (version == USB2_PORT) {
59		/* 1. power off and disable u2 port0 */
60		value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
61		value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
62		mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
63
64		/* 2. power on, enable u2 port0 and select its mode */
65		value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
66		value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
67		value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
68			(value & (~SSUSB_U2_PORT_HOST_SEL));
69		mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
70	} else {
71		/* 1. power off and disable u3 port0 */
72		value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
73		value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
74		mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
75
76		/* 2. power on, enable u3 port0 and select its mode */
77		value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
78		value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
79		value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
80			(value & (~SSUSB_U3_PORT_HOST_SEL));
81		mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
82	}
83
84	return 0;
85}
86
87static void switch_port_to_host(struct ssusb_mtk *ssusb)
88{
89	u32 check_clk = 0;
90
91	dev_dbg(ssusb->dev, "%s\n", __func__);
92
93	ssusb_port0_switch(ssusb, USB2_PORT, true);
94
95	if (ssusb->otg_switch.is_u3_drd) {
96		ssusb_port0_switch(ssusb, USB3_PORT, true);
97		check_clk = SSUSB_U3_MAC_RST_B_STS;
98	}
99
100	ssusb_check_clocks(ssusb, check_clk);
101
102	/* after all clocks are stable */
103	toggle_opstate(ssusb);
104}
105
106static void switch_port_to_device(struct ssusb_mtk *ssusb)
107{
108	u32 check_clk = 0;
109
110	dev_dbg(ssusb->dev, "%s\n", __func__);
111
112	ssusb_port0_switch(ssusb, USB2_PORT, false);
113
114	if (ssusb->otg_switch.is_u3_drd) {
115		ssusb_port0_switch(ssusb, USB3_PORT, false);
116		check_clk = SSUSB_U3_MAC_RST_B_STS;
117	}
118
119	ssusb_check_clocks(ssusb, check_clk);
120}
121
122int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
123{
124	struct ssusb_mtk *ssusb =
125		container_of(otg_sx, struct ssusb_mtk, otg_switch);
126	struct regulator *vbus = otg_sx->vbus;
127	int ret;
128
129	/* vbus is optional */
130	if (!vbus)
131		return 0;
132
133	dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
134
135	if (is_on) {
136		ret = regulator_enable(vbus);
137		if (ret) {
138			dev_err(ssusb->dev, "vbus regulator enable failed\n");
139			return ret;
140		}
141	} else {
142		regulator_disable(vbus);
143	}
144
145	return 0;
146}
147
148/*
149 * switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND
150 * switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID
151 */
152static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx,
153	enum mtu3_vbus_id_state status)
154{
155	struct ssusb_mtk *ssusb =
156		container_of(otg_sx, struct ssusb_mtk, otg_switch);
157	struct mtu3 *mtu = ssusb->u3d;
158
159	dev_dbg(ssusb->dev, "mailbox %s\n", mailbox_state_string(status));
160	mtu3_dbg_trace(ssusb->dev, "mailbox %s", mailbox_state_string(status));
161
162	switch (status) {
163	case MTU3_ID_GROUND:
164		switch_port_to_host(ssusb);
165		ssusb_set_vbus(otg_sx, 1);
166		ssusb->is_host = true;
167		break;
168	case MTU3_ID_FLOAT:
169		ssusb->is_host = false;
170		ssusb_set_vbus(otg_sx, 0);
171		switch_port_to_device(ssusb);
172		break;
173	case MTU3_VBUS_OFF:
174		mtu3_stop(mtu);
175		pm_relax(ssusb->dev);
176		break;
177	case MTU3_VBUS_VALID:
178		/* avoid suspend when works as device */
179		pm_stay_awake(ssusb->dev);
180		mtu3_start(mtu);
181		break;
182	default:
183		dev_err(ssusb->dev, "invalid state\n");
184	}
185}
186
187static void ssusb_id_work(struct work_struct *work)
188{
189	struct otg_switch_mtk *otg_sx =
190		container_of(work, struct otg_switch_mtk, id_work);
191
192	if (otg_sx->id_event)
193		ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
194	else
195		ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
196}
197
198static void ssusb_vbus_work(struct work_struct *work)
199{
200	struct otg_switch_mtk *otg_sx =
201		container_of(work, struct otg_switch_mtk, vbus_work);
202
203	if (otg_sx->vbus_event)
204		ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
205	else
206		ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
207}
208
209/*
210 * @ssusb_id_notifier is called in atomic context, but @ssusb_set_mailbox
211 * may sleep, so use work queue here
212 */
213static int ssusb_id_notifier(struct notifier_block *nb,
214	unsigned long event, void *ptr)
215{
216	struct otg_switch_mtk *otg_sx =
217		container_of(nb, struct otg_switch_mtk, id_nb);
218
219	otg_sx->id_event = event;
220	schedule_work(&otg_sx->id_work);
221
222	return NOTIFY_DONE;
223}
224
225static int ssusb_vbus_notifier(struct notifier_block *nb,
226	unsigned long event, void *ptr)
227{
228	struct otg_switch_mtk *otg_sx =
229		container_of(nb, struct otg_switch_mtk, vbus_nb);
230
231	otg_sx->vbus_event = event;
232	schedule_work(&otg_sx->vbus_work);
233
234	return NOTIFY_DONE;
235}
236
237static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
238{
239	struct ssusb_mtk *ssusb =
240		container_of(otg_sx, struct ssusb_mtk, otg_switch);
241	struct extcon_dev *edev = otg_sx->edev;
242	int ret;
243
244	/* extcon is optional */
245	if (!edev)
246		return 0;
247
248	otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier;
249	ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB,
250					&otg_sx->vbus_nb);
251	if (ret < 0) {
252		dev_err(ssusb->dev, "failed to register notifier for USB\n");
253		return ret;
254	}
255
256	otg_sx->id_nb.notifier_call = ssusb_id_notifier;
257	ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
258					&otg_sx->id_nb);
259	if (ret < 0) {
260		dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
261		return ret;
262	}
263
264	dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
265		extcon_get_state(edev, EXTCON_USB),
266		extcon_get_state(edev, EXTCON_USB_HOST));
267
268	/* default as host, switch to device mode if needed */
269	if (extcon_get_state(edev, EXTCON_USB_HOST) == false)
270		ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
271	if (extcon_get_state(edev, EXTCON_USB) == true)
272		ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
273
274	return 0;
275}
276
277/*
278 * We provide an interface via debugfs to switch between host and device modes
279 * depending on user input.
280 * This is useful in special cases, such as uses TYPE-A receptacle but also
281 * wants to support dual-role mode.
282 */
283void ssusb_mode_switch(struct ssusb_mtk *ssusb, int to_host)
284{
285	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
286
287	if (to_host) {
288		ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
289		ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
290		ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
291	} else {
292		ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
293		ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
294		ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
295	}
296}
297
298void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
299			  enum mtu3_dr_force_mode mode)
300{
301	u32 value;
302
303	value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
304	switch (mode) {
305	case MTU3_DR_FORCE_DEVICE:
306		value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
307		break;
308	case MTU3_DR_FORCE_HOST:
309		value |= SSUSB_U2_PORT_FORCE_IDDIG;
310		value &= ~SSUSB_U2_PORT_RG_IDDIG;
311		break;
312	case MTU3_DR_FORCE_NONE:
313		value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
314		break;
315	default:
316		return;
317	}
318	mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
319}
320
321static int ssusb_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
322{
323	struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
324	bool to_host = false;
325
326	if (role == USB_ROLE_HOST)
327		to_host = true;
328
329	if (to_host ^ ssusb->is_host)
330		ssusb_mode_switch(ssusb, to_host);
331
332	return 0;
333}
334
335static enum usb_role ssusb_role_sw_get(struct usb_role_switch *sw)
336{
337	struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
338	enum usb_role role;
339
340	role = ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
341
342	return role;
343}
344
345static int ssusb_role_sw_register(struct otg_switch_mtk *otg_sx)
346{
347	struct usb_role_switch_desc role_sx_desc = { 0 };
348	struct ssusb_mtk *ssusb =
349		container_of(otg_sx, struct ssusb_mtk, otg_switch);
350
351	if (!otg_sx->role_sw_used)
352		return 0;
353
354	role_sx_desc.set = ssusb_role_sw_set;
355	role_sx_desc.get = ssusb_role_sw_get;
356	role_sx_desc.fwnode = dev_fwnode(ssusb->dev);
357	role_sx_desc.driver_data = ssusb;
358	otg_sx->role_sw = usb_role_switch_register(ssusb->dev, &role_sx_desc);
359
360	return PTR_ERR_OR_ZERO(otg_sx->role_sw);
361}
362
363int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
364{
365	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
366	int ret = 0;
367
368	INIT_WORK(&otg_sx->id_work, ssusb_id_work);
369	INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work);
370
371	if (otg_sx->manual_drd_enabled)
372		ssusb_dr_debugfs_init(ssusb);
373	else if (otg_sx->role_sw_used)
374		ret = ssusb_role_sw_register(otg_sx);
375	else
376		ret = ssusb_extcon_register(otg_sx);
377
378	return ret;
379}
380
381void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
382{
383	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
384
385	cancel_work_sync(&otg_sx->id_work);
386	cancel_work_sync(&otg_sx->vbus_work);
387	usb_role_switch_unregister(otg_sx->role_sw);
388}
389