xref: /linux/drivers/usb/mtu3/mtu3_dr.c (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)
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 
otg_sx_to_ssusb(struct otg_switch_mtk * otg_sx)17 static 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 
toggle_opstate(struct ssusb_mtk * ssusb)22 static 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 */
ssusb_port0_switch(struct ssusb_mtk * ssusb,int version,bool tohost)29 static 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 
switch_port_to_host(struct ssusb_mtk * ssusb)67 static 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 
switch_port_to_device(struct ssusb_mtk * ssusb)86 static 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 
ssusb_set_vbus(struct otg_switch_mtk * otg_sx,int is_on)102 int 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 
ssusb_mode_sw_work(struct work_struct * work)127 static 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 
ssusb_set_mode(struct otg_switch_mtk * otg_sx,enum usb_role role)174 static 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 
ssusb_id_notifier(struct notifier_block * nb,unsigned long event,void * ptr)185 static 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 
ssusb_extcon_register(struct otg_switch_mtk * otg_sx)196 static 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  */
ssusb_mode_switch(struct ssusb_mtk * ssusb,int to_host)230 void 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 
ssusb_set_force_mode(struct ssusb_mtk * ssusb,enum mtu3_dr_force_mode mode)237 void 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 
ssusb_role_sw_set(struct usb_role_switch * sw,enum usb_role role)260 static 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 
ssusb_role_sw_get(struct usb_role_switch * sw)270 static 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 
ssusb_role_sw_register(struct otg_switch_mtk * otg_sx)277 static 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 
ssusb_otg_switch_init(struct ssusb_mtk * ssusb)307 int 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 
ssusb_otg_switch_exit(struct ssusb_mtk * ssusb)324 void 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