drivers/usb/mtu3/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 "mtu3.h"
  11 #include "mtu3_dr.h"
  12 #include "mtu3_debug.h"
  13
  14 #define USB2_PORT 2
  15 #define USB3_PORT 3
  16
  17 enum mtu3_vbus_id_state {
  18         MTU3_ID_FLOAT = 1,
  19         MTU3_ID_GROUND,
  20         MTU3_VBUS_OFF,
  21         MTU3_VBUS_VALID,
  22 };
  23
  24 static char *mailbox_state_string(enum mtu3_vbus_id_state state)
  25 {
  26         switch (state) {
  27         case MTU3_ID_FLOAT:
  28                 return "ID_FLOAT";
  29         case MTU3_ID_GROUND:
  30                 return "ID_GROUND";
  31         case MTU3_VBUS_OFF:
  32                 return "VBUS_OFF";
  33         case MTU3_VBUS_VALID:
  34                 return "VBUS_VALID";
  35         default:
  36                 return "UNKNOWN";
  37         }
  38 }
  39
  40 static void toggle_opstate(struct ssusb_mtk *ssusb)
  41 {
  42         if (!ssusb->otg_switch.is_u3_drd) {
  43                 mtu3_setbits(ssusb->mac_base, U3D_DEVICE_CONTROL, DC_SESSION);
  44                 mtu3_setbits(ssusb->mac_base, U3D_POWER_MANAGEMENT, SOFT_CONN);
  45         }
  46 }
  47
  48 /* only port0 supports dual-role mode */
  49 static int ssusb_port0_switch(struct ssusb_mtk *ssusb,
  50         int version, bool tohost)
  51 {
  52         void __iomem *ibase = ssusb->ippc_base;
  53         u32 value;
  54
  55         dev_dbg(ssusb->dev, "%s (switch u%d port0 to %s)\n", __func__,
  56                 version, tohost ? "host" : "device");
  57
  58         if (version == USB2_PORT) {
  59                 /* 1. power off and disable u2 port0 */
  60                 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  61                 value |= SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS;
  62                 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  63
  64                 /* 2. power on, enable u2 port0 and select its mode */
  65                 value = mtu3_readl(ibase, SSUSB_U2_CTRL(0));
  66                 value &= ~(SSUSB_U2_PORT_PDN | SSUSB_U2_PORT_DIS);
  67                 value = tohost ? (value | SSUSB_U2_PORT_HOST_SEL) :
  68                         (value & (~SSUSB_U2_PORT_HOST_SEL));
  69                 mtu3_writel(ibase, SSUSB_U2_CTRL(0), value);
  70         } else {
  71                 /* 1. power off and disable u3 port0 */
  72                 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  73                 value |= SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS;
  74                 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  75
  76                 /* 2. power on, enable u3 port0 and select its mode */
  77                 value = mtu3_readl(ibase, SSUSB_U3_CTRL(0));
  78                 value &= ~(SSUSB_U3_PORT_PDN | SSUSB_U3_PORT_DIS);
  79                 value = tohost ? (value | SSUSB_U3_PORT_HOST_SEL) :
  80                         (value & (~SSUSB_U3_PORT_HOST_SEL));
  81                 mtu3_writel(ibase, SSUSB_U3_CTRL(0), value);
  82         }
  83
  84         return 0;
  85 }
  86
  87 static void switch_port_to_host(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, true);
  94
  95         if (ssusb->otg_switch.is_u3_drd) {
  96                 ssusb_port0_switch(ssusb, USB3_PORT, true);
  97                 check_clk = SSUSB_U3_MAC_RST_B_STS;
  98         }
  99
 100         ssusb_check_clocks(ssusb, check_clk);
 101
 102         /* after all clocks are stable */
 103         toggle_opstate(ssusb);
 104 }
 105
 106 static void switch_port_to_device(struct ssusb_mtk *ssusb)
 107 {
 108         u32 check_clk = 0;
 109
 110         dev_dbg(ssusb->dev, "%s\n", __func__);
 111
 112         ssusb_port0_switch(ssusb, USB2_PORT, false);
 113
 114         if (ssusb->otg_switch.is_u3_drd) {
 115                 ssusb_port0_switch(ssusb, USB3_PORT, false);
 116                 check_clk = SSUSB_U3_MAC_RST_B_STS;
 117         }
 118
 119         ssusb_check_clocks(ssusb, check_clk);
 120 }
 121
 122 int ssusb_set_vbus(struct otg_switch_mtk *otg_sx, int is_on)
 123 {
 124         struct ssusb_mtk *ssusb =
 125                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 126         struct regulator *vbus = otg_sx->vbus;
 127         int ret;
 128
 129         /* vbus is optional */
 130         if (!vbus)
 131                 return 0;
 132
 133         dev_dbg(ssusb->dev, "%s: turn %s\n", __func__, is_on ? "on" : "off");
 134
 135         if (is_on) {
 136                 ret = regulator_enable(vbus);
 137                 if (ret) {
 138                         dev_err(ssusb->dev, "vbus regulator enable failed\n");
 139                         return ret;
 140                 }
 141         } else {
 142                 regulator_disable(vbus);
 143         }
 144
 145         return 0;
 146 }
 147
 148 /*
 149  * switch to host: -> MTU3_VBUS_OFF --> MTU3_ID_GROUND
 150  * switch to device: -> MTU3_ID_FLOAT --> MTU3_VBUS_VALID
 151  */
 152 static void ssusb_set_mailbox(struct otg_switch_mtk *otg_sx,
 153         enum mtu3_vbus_id_state status)
 154 {
 155         struct ssusb_mtk *ssusb =
 156                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 157         struct mtu3 *mtu = ssusb->u3d;
 158
 159         dev_dbg(ssusb->dev, "mailbox %s\n", mailbox_state_string(status));
 160         mtu3_dbg_trace(ssusb->dev, "mailbox %s", mailbox_state_string(status));
 161
 162         switch (status) {
 163         case MTU3_ID_GROUND:
 164                 switch_port_to_host(ssusb);
 165                 ssusb_set_vbus(otg_sx, 1);
 166                 ssusb->is_host = true;
 167                 break;
 168         case MTU3_ID_FLOAT:
 169                 ssusb->is_host = false;
 170                 ssusb_set_vbus(otg_sx, 0);
 171                 switch_port_to_device(ssusb);
 172                 break;
 173         case MTU3_VBUS_OFF:
 174                 mtu3_stop(mtu);
 175                 pm_relax(ssusb->dev);
 176                 break;
 177         case MTU3_VBUS_VALID:
 178                 /* avoid suspend when works as device */
 179                 pm_stay_awake(ssusb->dev);
 180                 mtu3_start(mtu);
 181                 break;
 182         default:
 183                 dev_err(ssusb->dev, "invalid state\n");
 184         }
 185 }
 186
 187 static void ssusb_id_work(struct work_struct *work)
 188 {
 189         struct otg_switch_mtk *otg_sx =
 190                 container_of(work, struct otg_switch_mtk, id_work);
 191
 192         if (otg_sx->id_event)
 193                 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
 194         else
 195                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 196 }
 197
 198 static void ssusb_vbus_work(struct work_struct *work)
 199 {
 200         struct otg_switch_mtk *otg_sx =
 201                 container_of(work, struct otg_switch_mtk, vbus_work);
 202
 203         if (otg_sx->vbus_event)
 204                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 205         else
 206                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
 207 }
 208
 209 /*
 210  * @ssusb_id_notifier is called in atomic context, but @ssusb_set_mailbox
 211  * may sleep, so use work queue here
 212  */
 213 static int ssusb_id_notifier(struct notifier_block *nb,
 214         unsigned long event, void *ptr)
 215 {
 216         struct otg_switch_mtk *otg_sx =
 217                 container_of(nb, struct otg_switch_mtk, id_nb);
 218
 219         otg_sx->id_event = event;
 220         schedule_work(&otg_sx->id_work);
 221
 222         return NOTIFY_DONE;
 223 }
 224
 225 static int ssusb_vbus_notifier(struct notifier_block *nb,
 226         unsigned long event, void *ptr)
 227 {
 228         struct otg_switch_mtk *otg_sx =
 229                 container_of(nb, struct otg_switch_mtk, vbus_nb);
 230
 231         otg_sx->vbus_event = event;
 232         schedule_work(&otg_sx->vbus_work);
 233
 234         return NOTIFY_DONE;
 235 }
 236
 237 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
 238 {
 239         struct ssusb_mtk *ssusb =
 240                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 241         struct extcon_dev *edev = otg_sx->edev;
 242         int ret;
 243
 244         /* extcon is optional */
 245         if (!edev)
 246                 return 0;
 247
 248         otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier;
 249         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB,
 250                                         &otg_sx->vbus_nb);
 251         if (ret < 0) {
 252                 dev_err(ssusb->dev, "failed to register notifier for USB\n");
 253                 return ret;
 254         }
 255
 256         otg_sx->id_nb.notifier_call = ssusb_id_notifier;
 257         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
 258                                         &otg_sx->id_nb);
 259         if (ret < 0) {
 260                 dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
 261                 return ret;
 262         }
 263
 264         dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
 265                 extcon_get_state(edev, EXTCON_USB),
 266                 extcon_get_state(edev, EXTCON_USB_HOST));
 267
 268         /* default as host, switch to device mode if needed */
 269         if (extcon_get_state(edev, EXTCON_USB_HOST) == false)
 270                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 271         if (extcon_get_state(edev, EXTCON_USB) == true)
 272                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 273
 274         return 0;
 275 }
 276
 277 /*
 278  * We provide an interface via debugfs to switch between host and device modes
 279  * depending on user input.
 280  * This is useful in special cases, such as uses TYPE-A receptacle but also
 281  * wants to support dual-role mode.
 282  */
 283 void ssusb_mode_manual_switch(struct ssusb_mtk *ssusb, int to_host)
 284 {
 285         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 286
 287         if (to_host) {
 288                 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_HOST);
 289                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
 290                 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
 291         } else {
 292                 ssusb_set_force_mode(ssusb, MTU3_DR_FORCE_DEVICE);
 293                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 294                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 295         }
 296 }
 297
 298 void ssusb_set_force_mode(struct ssusb_mtk *ssusb,
 299                           enum mtu3_dr_force_mode mode)
 300 {
 301         u32 value;
 302
 303         value = mtu3_readl(ssusb->ippc_base, SSUSB_U2_CTRL(0));
 304         switch (mode) {
 305         case MTU3_DR_FORCE_DEVICE:
 306                 value |= SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG;
 307                 break;
 308         case MTU3_DR_FORCE_HOST:
 309                 value |= SSUSB_U2_PORT_FORCE_IDDIG;
 310                 value &= ~SSUSB_U2_PORT_RG_IDDIG;
 311                 break;
 312         case MTU3_DR_FORCE_NONE:
 313                 value &= ~(SSUSB_U2_PORT_FORCE_IDDIG | SSUSB_U2_PORT_RG_IDDIG);
 314                 break;
 315         default:
 316                 return;
 317         }
 318         mtu3_writel(ssusb->ippc_base, SSUSB_U2_CTRL(0), value);
 319 }
 320
 321 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
 322 {
 323         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 324         int ret = 0;
 325
 326         INIT_WORK(&otg_sx->id_work, ssusb_id_work);
 327         INIT_WORK(&otg_sx->vbus_work, ssusb_vbus_work);
 328
 329         if (otg_sx->manual_drd_enabled)
 330                 ssusb_dr_debugfs_init(ssusb);
 331         else
 332                 ret = ssusb_extcon_register(otg_sx);
 333
 334         return ret;
 335 }
 336
 337 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
 338 {
 339         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 340
 341         cancel_work_sync(&otg_sx->id_work);
 342         cancel_work_sync(&otg_sx->vbus_work);
 343 }