root/drivers/usb/mtu3/mtu3_dr.c

DEFINITIONS

1. mailbox_state_string
2. toggle_opstate
3. ssusb_port0_switch
4. switch_port_to_host
5. switch_port_to_device
6. ssusb_set_vbus
7. ssusb_set_mailbox
8. ssusb_id_work
9. ssusb_vbus_work
10. ssusb_id_notifier
11. ssusb_vbus_notifier
12. ssusb_extcon_register
13. ssusb_mode_switch
14. ssusb_set_force_mode
15. ssusb_role_sw_set
16. ssusb_role_sw_get
17. ssusb_role_sw_register
18. ssusb_otg_switch_init
19. ssusb_otg_switch_exit

   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 device *dev, enum usb_role role)
 324 {
 325         struct ssusb_mtk *ssusb = dev_get_drvdata(dev);
 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 device *dev)
 338 {
 339         struct ssusb_mtk *ssusb = dev_get_drvdata(dev);
 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         otg_sx->role_sw = usb_role_switch_register(ssusb->dev, &role_sx_desc);
 360 
 361         return PTR_ERR_OR_ZERO(otg_sx->role_sw);
 362 }
 363 
 364 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
 365 {
 366         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 367         int ret = 0;
 368 
 369         INIT_WORK(&otg_sx->id_work, ssusb_id_work);
 370         INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work);
 371 
 372         if (otg_sx->manual_drd_enabled)
 373                 ssusb_dr_debugfs_init(ssusb);
 374         else if (otg_sx->role_sw_used)
 375                 ret = ssusb_role_sw_register(otg_sx);
 376         else
 377                 ret = ssusb_extcon_register(otg_sx);
 378 
 379         return ret;
 380 }
 381 
 382 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
 383 {
 384         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 385 
 386         cancel_work_sync(&otg_sx->id_work);
 387         cancel_work_sync(&otg_sx->vbus_work);
 388         usb_role_switch_unregister(otg_sx->role_sw);
 389 }