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 "mtu3.h"
11#include "mtu3_dr.h"
12#include "mtu3_debug.h"
13
14#define USB2_PORT 2
15#define USB3_PORT 3
16
17static inline struct ssusb_mtk *otg_sx_to_ssusb(struct otg_switch_mtk *otg_sx)
18{
19	return container_of(otg_sx, struct ssusb_mtk, otg_switch);
20}
21
22static void toggle_opstate(struct ssusb_mtk *ssusb)
23{
24	mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
25	mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
26}
27
28/* only port0 supports dual-role mode */
29static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
30	int version, bool tohost)
31{
32	void __iomem *ibase = ssusb->ippc_base;
33	u32 value;
34
35	dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
36		version, tohost ? "host" : "device");
37
38	if (version == USB2_PORT) {
39		/* 1. power off and disable u2 port0 */
40		value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
41		value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
42		mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
43
44		/* 2. power on, enable u2 port0 and select its mode */
45		value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
46		value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
47		value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
48			(value & (~SSUSB_U2_PORT_HOST_SEL));
49		mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
50	} else {
51		/* 1. power off and disable u3 port0 */
52		value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
53		value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
54		mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
55
56		/* 2. power on, enable u3 port0 and select its mode */
57		value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
58		value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
59		value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
60			(value & (~SSUSB_U3_PORT_HOST_SEL));
61		mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
62	}
63
64	return 0;
65}
66
67static void switch_port_to_host(struct ssusb_mtk *ssusb)
68{
69	u32 check_clk = 0;
70
71	dev_dbg(ssusb->dev, "%s\n", __func__);
72
73	ssusb_port0_switch(ssusb, USB2_PORT, true);
74
75	if (ssusb->otg_switch.is_u3_drd) {
76		ssusb_port0_switch(ssusb, USB3_PORT, true);
77		check_clk = SSUSB_U3_MAC_RST_B_STS;
78	}
79
80	ssusb_check_clocks(ssusb, check_clk);
81
82	/* after all clocks are stable */
83	toggle_opstate(ssusb);
84}
85
86static void switch_port_to_device(struct ssusb_mtk *ssusb)
87{
88	u32 check_clk = 0;
89
90	dev_dbg(ssusb->dev, "%s\n", __func__);
91
92	ssusb_port0_switch(ssusb, USB2_PORT, false);
93
94	if (ssusb->otg_switch.is_u3_drd) {
95		ssusb_port0_switch(ssusb, USB3_PORT, false);
96		check_clk = SSUSB_U3_MAC_RST_B_STS;
97	}
98
99	ssusb_check_clocks(ssusb, check_clk);
100}
101
102int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
103{
104	struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
105	struct regulator *vbus = otg_sx->vbus;
106	int ret;
107
108	/* vbus is optional */
109	if (!vbus)
110		return 0;
111
112	dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
113
114	if (is_on) {
115		ret = regulator_enable(vbus);
116		if (ret) {
117			dev_err(ssusb->dev, "vbus regulator enable failed\n");
118			return ret;
119		}
120	} else {
121		regulator_disable(vbus);
122	}
123
124	return 0;
125}
126
127static void ssusb_mode_sw_work(struct work_struct *work)
128{
129	struct otg_switch_mtk *otg_sx =
130		container_of(work, struct otg_switch_mtk, dr_work);
131	struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
132	struct mtu3 *mtu = ssusb->u3d;
133	enum usb_role desired_role = otg_sx->desired_role;
134	enum usb_role current_role;
135
136	current_role = ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
137
138	if (desired_role == USB_ROLE_NONE) {
139		/* the default mode is host as probe does */
140		desired_role = USB_ROLE_HOST;
141		if (otg_sx->default_role == USB_ROLE_DEVICE)
142			desired_role = USB_ROLE_DEVICE;
143	}
144
145	if (current_role == desired_role)
146		return;
147
148	dev_dbg(ssusb->dev, "set role : %s\n", usb_role_string(desired_role));
149	mtu3_dbg_trace(ssusb->dev, "set role : %s", usb_role_string(desired_role));
150	pm_runtime_get_sync(ssusb->dev);
151
152	switch (desired_role) {
153	case USB_ROLE_HOST:
154		ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
155		mtu3_stop(mtu);
156		switch_port_to_host(ssusb);
157		ssusb_set_vbus(otg_sx, 1);
158		ssusb->is_host = true;
159		break;
160	case USB_ROLE_DEVICE:
161		ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
162		ssusb->is_host = false;
163		ssusb_set_vbus(otg_sx, 0);
164		switch_port_to_device(ssusb);
165		mtu3_start(mtu);
166		break;
167	case USB_ROLE_NONE:
168	default:
169		dev_err(ssusb->dev, "invalid role\n");
170	}
171	pm_runtime_put(ssusb->dev);
172}
173
174static void ssusb_set_mode(struct otg_switch_mtk *otg_sx, enum usb_role role)
175{
176	struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
177
178	if (ssusb->dr_mode != USB_DR_MODE_OTG)
179		return;
180
181	otg_sx->desired_role = role;
182	queue_work(system_freezable_wq, &otg_sx->dr_work);
183}
184
185static int ssusb_id_notifier(struct notifier_block *nb,
186	unsigned long event, void *ptr)
187{
188	struct otg_switch_mtk *otg_sx =
189		container_of(nb, struct otg_switch_mtk, id_nb);
190
191	ssusb_set_mode(otg_sx, event ? USB_ROLE_HOST : USB_ROLE_DEVICE);
192
193	return NOTIFY_DONE;
194}
195
196static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
197{
198	struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
199	struct extcon_dev *edev = otg_sx->edev;
200	int ret;
201
202	/* extcon is optional */
203	if (!edev)
204		return 0;
205
206	otg_sx->id_nb.notifier_call = ssusb_id_notifier;
207	ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
208					&otg_sx->id_nb);
209	if (ret < 0) {
210		dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
211		return ret;
212	}
213
214	ret = extcon_get_state(edev, EXTCON_USB_HOST);
215	dev_dbg(ssusb->dev, "EXTCON_USB_HOST: %d\n", ret);
216
217	/* default as host, switch to device mode if needed */
218	if (!ret)
219		ssusb_set_mode(otg_sx, USB_ROLE_DEVICE);
220
221	return 0;
222}
223
224/*
225 * We provide an interface via debugfs to switch between host and device modes
226 * depending on user input.
227 * This is useful in special cases, such as uses TYPE-A receptacle but also
228 * wants to support dual-role mode.
229 */
230void ssusb_mode_switch(struct ssusb_mtk *ssusb, int to_host)
231{
232	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
233
234	ssusb_set_mode(otg_sx, to_host ? USB_ROLE_HOST : USB_ROLE_DEVICE);
235}
236
237void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
238			  enum mtu3_dr_force_mode mode)
239{
240	u32 value;
241
242	value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
243	switch (mode) {
244	case MTU3_DR_FORCE_DEVICE:
245		value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
246		break;
247	case MTU3_DR_FORCE_HOST:
248		value |= SSUSB_U2_PORT_FORCE_IDDIG;
249		value &= ~SSUSB_U2_PORT_RG_IDDIG;
250		break;
251	case MTU3_DR_FORCE_NONE:
252		value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
253		break;
254	default:
255		return;
256	}
257	mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
258}
259
260static int ssusb_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
261{
262	struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
263	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
264
265	ssusb_set_mode(otg_sx, role);
266
267	return 0;
268}
269
270static enum usb_role ssusb_role_sw_get(struct usb_role_switch *sw)
271{
272	struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw);
273
274	return ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE;
275}
276
277static int ssusb_role_sw_register(struct otg_switch_mtk *otg_sx)
278{
279	struct usb_role_switch_desc role_sx_desc = { 0 };
280	struct ssusb_mtk *ssusb = otg_sx_to_ssusb(otg_sx);
281	struct device *dev = ssusb->dev;
282	enum usb_dr_mode mode;
283
284	if (!otg_sx->role_sw_used)
285		return 0;
286
287	mode = usb_get_role_switch_default_mode(dev);
288	if (mode == USB_DR_MODE_PERIPHERAL)
289		otg_sx->default_role = USB_ROLE_DEVICE;
290	else
291		otg_sx->default_role = USB_ROLE_HOST;
292
293	role_sx_desc.set = ssusb_role_sw_set;
294	role_sx_desc.get = ssusb_role_sw_get;
295	role_sx_desc.fwnode = dev_fwnode(dev);
296	role_sx_desc.driver_data = ssusb;
297	role_sx_desc.allow_userspace_control = true;
298	otg_sx->role_sw = usb_role_switch_register(dev, &role_sx_desc);
299	if (IS_ERR(otg_sx->role_sw))
300		return PTR_ERR(otg_sx->role_sw);
301
302	ssusb_set_mode(otg_sx, otg_sx->default_role);
303
304	return 0;
305}
306
307int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
308{
309	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
310	int ret = 0;
311
312	INIT_WORK(&otg_sx->dr_work, ssusb_mode_sw_work);
313
314	if (otg_sx->manual_drd_enabled)
315		ssusb_dr_debugfs_init(ssusb);
316	else if (otg_sx->role_sw_used)
317		ret = ssusb_role_sw_register(otg_sx);
318	else
319		ret = ssusb_extcon_register(otg_sx);
320
321	return ret;
322}
323
324void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
325{
326	struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
327
328	cancel_work_sync(&otg_sx->dr_work);
329	usb_role_switch_unregister(otg_sx->role_sw);
330}
331