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 19 enum mtu3_vbus_id_state { 20 MTU3_ID_FLOAT = 1, 21 MTU3_ID_GROUND, 22 MTU3_VBUS_OFF, 23 MTU3_VBUS_VALID, 24 }; 25 26 static 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 42 static void toggle_opstate(struct ssusb_mtk *ssusb) 43 { 44 if (!ssusb->otg_switch.is_u3_drd) { 45 mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION); 46 mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN); 47 } 48 } 49 50 /* only port0 supports dual-role mode */ 51 static int ssusb_port0_switch(struct ssusb_mtk *ssusb, 52 int version, bool tohost) 53 { 54 void __iomem *ibase = ssusb->ippc_base; 55 u32 value; 56 57 dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__, 58 version, tohost ? "host" : "device"); 59 60 if (version == USB2_PORT) { 61 /* 1. power off and disable u2 port0 */ 62 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0)); 63 value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS; 64 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value); 65 66 /* 2. power on, enable u2 port0 and select its mode */ 67 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0)); 68 value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS); 69 value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) : 70 (value & (~SSUSB_U2_PORT_HOST_SEL)); 71 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value); 72 } else { 73 /* 1. power off and disable u3 port0 */ 74 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0)); 75 value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS; 76 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value); 77 78 /* 2. power on, enable u3 port0 and select its mode */ 79 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0)); 80 value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS); 81 value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) : 82 (value & (~SSUSB_U3_PORT_HOST_SEL)); 83 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value); 84 } 85 86 return 0; 87 } 88 89 static void switch_port_to_host(struct ssusb_mtk *ssusb) 90 { 91 u32 check_clk = 0; 92 93 dev_dbg(ssusb->dev, "%s\n", __func__); 94 95 ssusb_port0_switch(ssusb, USB2_PORT, true); 96 97 if (ssusb->otg_switch.is_u3_drd) { 98 ssusb_port0_switch(ssusb, USB3_PORT, true); 99 check_clk = SSUSB_U3_MAC_RST_B_STS; 100 } 101 102 ssusb_check_clocks(ssusb, check_clk); 103 104 /* after all clocks are stable */ 105 toggle_opstate(ssusb); 106 } 107 108 static void switch_port_to_device(struct ssusb_mtk *ssusb) 109 { 110 u32 check_clk = 0; 111 112 dev_dbg(ssusb->dev, "%s\n", __func__); 113 114 ssusb_port0_switch(ssusb, USB2_PORT, false); 115 116 if (ssusb->otg_switch.is_u3_drd) { 117 ssusb_port0_switch(ssusb, USB3_PORT, false); 118 check_clk = SSUSB_U3_MAC_RST_B_STS; 119 } 120 121 ssusb_check_clocks(ssusb, check_clk); 122 } 123 124 int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on) 125 { 126 struct ssusb_mtk *ssusb = 127 container_of(otg_sx, struct ssusb_mtk, otg_switch); 128 struct regulator *vbus = otg_sx->vbus; 129 int ret; 130 131 /* vbus is optional */ 132 if (!vbus) 133 return 0; 134 135 dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off"); 136 137 if (is_on) { 138 ret = regulator_enable(vbus); 139 if (ret) { 140 dev_err(ssusb->dev, "vbus regulator enable failed\n"); 141 return ret; 142 } 143 } else { 144 regulator_disable(vbus); 145 } 146 147 return 0; 148 } 149 150 /* 151 * switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND 152 * switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID 153 */ 154 static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx, 155 enum mtu3_vbus_id_state status) 156 { 157 struct ssusb_mtk *ssusb = 158 container_of(otg_sx, struct ssusb_mtk, otg_switch); 159 struct mtu3 *mtu = ssusb->u3d; 160 161 dev_dbg(ssusb->dev, "mailbox %s\n", mailbox_state_string(status)); 162 mtu3_dbg_trace(ssusb->dev, "mailbox %s", mailbox_state_string(status)); 163 164 switch (status) { 165 case MTU3_ID_GROUND: 166 switch_port_to_host(ssusb); 167 ssusb_set_vbus(otg_sx, 1); 168 ssusb->is_host = true; 169 break; 170 case MTU3_ID_FLOAT: 171 ssusb->is_host = false; 172 ssusb_set_vbus(otg_sx, 0); 173 switch_port_to_device(ssusb); 174 break; 175 case MTU3_VBUS_OFF: 176 mtu3_stop(mtu); 177 pm_relax(ssusb->dev); 178 break; 179 case MTU3_VBUS_VALID: 180 /* avoid suspend when works as device */ 181 pm_stay_awake(ssusb->dev); 182 mtu3_start(mtu); 183 break; 184 default: 185 dev_err(ssusb->dev, "invalid state\n"); 186 } 187 } 188 189 static void ssusb_id_work(struct work_struct *work) 190 { 191 struct otg_switch_mtk *otg_sx = 192 container_of(work, struct otg_switch_mtk, id_work); 193 194 if (otg_sx->id_event) 195 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND); 196 else 197 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT); 198 } 199 200 static void ssusb_vbus_work(struct work_struct *work) 201 { 202 struct otg_switch_mtk *otg_sx = 203 container_of(work, struct otg_switch_mtk, vbus_work); 204 205 if (otg_sx->vbus_event) 206 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID); 207 else 208 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF); 209 } 210 211 /* 212 * @ssusb_id_notifier is called in atomic context, but @ssusb_set_mailbox 213 * may sleep, so use work queue here 214 */ 215 static int ssusb_id_notifier(struct notifier_block *nb, 216 unsigned long event, void *ptr) 217 { 218 struct otg_switch_mtk *otg_sx = 219 container_of(nb, struct otg_switch_mtk, id_nb); 220 221 otg_sx->id_event = event; 222 schedule_work(&otg_sx->id_work); 223 224 return NOTIFY_DONE; 225 } 226 227 static int ssusb_vbus_notifier(struct notifier_block *nb, 228 unsigned long event, void *ptr) 229 { 230 struct otg_switch_mtk *otg_sx = 231 container_of(nb, struct otg_switch_mtk, vbus_nb); 232 233 otg_sx->vbus_event = event; 234 schedule_work(&otg_sx->vbus_work); 235 236 return NOTIFY_DONE; 237 } 238 239 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx) 240 { 241 struct ssusb_mtk *ssusb = 242 container_of(otg_sx, struct ssusb_mtk, otg_switch); 243 struct extcon_dev *edev = otg_sx->edev; 244 int ret; 245 246 /* extcon is optional */ 247 if (!edev) 248 return 0; 249 250 otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier; 251 ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB, 252 &otg_sx->vbus_nb); 253 if (ret < 0) { 254 dev_err(ssusb->dev, "failed to register notifier for USB\n"); 255 return ret; 256 } 257 258 otg_sx->id_nb.notifier_call = ssusb_id_notifier; 259 ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST, 260 &otg_sx->id_nb); 261 if (ret < 0) { 262 dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n"); 263 return ret; 264 } 265 266 dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n", 267 extcon_get_state(edev, EXTCON_USB), 268 extcon_get_state(edev, EXTCON_USB_HOST)); 269 270 /* default as host, switch to device mode if needed */ 271 if (extcon_get_state(edev, EXTCON_USB_HOST) == false) 272 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT); 273 if (extcon_get_state(edev, EXTCON_USB) == true) 274 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID); 275 276 return 0; 277 } 278 279 /* 280 * We provide an interface via debugfs to switch between host and device modes 281 * depending on user input. 282 * This is useful in special cases, such as uses TYPE-A receptacle but also 283 * wants to support dual-role mode. 284 */ 285 void ssusb_mode_switch(struct ssusb_mtk *ssusb, int to_host) 286 { 287 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 288 289 if (to_host) { 290 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST); 291 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF); 292 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND); 293 } else { 294 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE); 295 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT); 296 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID); 297 } 298 } 299 300 void ssusb_set_force_mode(struct ssusb_mtk *ssusb, 301 enum mtu3_dr_force_mode mode) 302 { 303 u32 value; 304 305 value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0)); 306 switch (mode) { 307 case MTU3_DR_FORCE_DEVICE: 308 value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG; 309 break; 310 case MTU3_DR_FORCE_HOST: 311 value |= SSUSB_U2_PORT_FORCE_IDDIG; 312 value &= ~SSUSB_U2_PORT_RG_IDDIG; 313 break; 314 case MTU3_DR_FORCE_NONE: 315 value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG); 316 break; 317 default: 318 return; 319 } 320 mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value); 321 } 322 323 static int ssusb_role_sw_set(struct usb_role_switch *sw, enum usb_role role) 324 { 325 struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw); 326 bool to_host = false; 327 328 if (role == USB_ROLE_HOST) 329 to_host = true; 330 331 if (to_host ^ ssusb->is_host) 332 ssusb_mode_switch(ssusb, to_host); 333 334 return 0; 335 } 336 337 static enum usb_role ssusb_role_sw_get(struct usb_role_switch *sw) 338 { 339 struct ssusb_mtk *ssusb = usb_role_switch_get_drvdata(sw); 340 enum usb_role role; 341 342 role = ssusb->is_host ? USB_ROLE_HOST : USB_ROLE_DEVICE; 343 344 return role; 345 } 346 347 static int ssusb_role_sw_register(struct otg_switch_mtk *otg_sx) 348 { 349 struct usb_role_switch_desc role_sx_desc = { 0 }; 350 struct ssusb_mtk *ssusb = 351 container_of(otg_sx, struct ssusb_mtk, otg_switch); 352 353 if (!otg_sx->role_sw_used) 354 return 0; 355 356 role_sx_desc.set = ssusb_role_sw_set; 357 role_sx_desc.get = ssusb_role_sw_get; 358 role_sx_desc.fwnode = dev_fwnode(ssusb->dev); 359 role_sx_desc.driver_data = ssusb; 360 otg_sx->role_sw = usb_role_switch_register(ssusb->dev, &role_sx_desc); 361 362 return PTR_ERR_OR_ZERO(otg_sx->role_sw); 363 } 364 365 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb) 366 { 367 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 368 int ret = 0; 369 370 INIT_WORK(&otg_sx->id_work, ssusb_id_work); 371 INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work); 372 373 if (otg_sx->manual_drd_enabled) 374 ssusb_dr_debugfs_init(ssusb); 375 else if (otg_sx->role_sw_used) 376 ret = ssusb_role_sw_register(otg_sx); 377 else 378 ret = ssusb_extcon_register(otg_sx); 379 380 return ret; 381 } 382 383 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb) 384 { 385 struct otg_switch_mtk *otg_sx = &ssusb->otg_switch; 386 387 cancel_work_sync(&otg_sx->id_work); 388 cancel_work_sync(&otg_sx->vbus_work); 389 usb_role_switch_unregister(otg_sx->role_sw); 390 } 391