mtu3_dr.c

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