drivers/usb/mtu3/mtu3_dr.c

   1 /*
   2  * mtu3_dr.c - dual role switch and host glue layer
   3  *
   4  * Copyright (C) 2016 MediaTek Inc.
   5  *
   6  * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
   7  *
   8  * This software is licensed under the terms of the GNU General Public
   9  * License version 2, as published by the Free Software Foundation, and
  10  * may be copied, distributed, and modified under those terms.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  */
  18
  19 #include <linux/debugfs.h>
  20 #include <linux/irq.h>
  21 #include <linux/kernel.h>
  22 #include <linux/of_device.h>
  23 #include <linux/pinctrl/consumer.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/uaccess.h>
  26
  27 #include "mtu3.h"
  28 #include "mtu3_dr.h"
  29
  30 #define USB2_PORT 2
  31 #define USB3_PORT 3
  32
  33 enum mtu3_vbus_id_state {
  34         MTU3_ID_FLOAT = 1,
  35         MTU3_ID_GROUND,
  36         MTU3_VBUS_OFF,
  37         MTU3_VBUS_VALID,
  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 state(%d)\n", status);
 160
 161         switch (status) {
 162         case MTU3_ID_GROUND:
 163                 switch_port_to_host(ssusb);
 164                 ssusb_set_vbus(otg_sx, 1);
 165                 ssusb->is_host = true;
 166                 break;
 167         case MTU3_ID_FLOAT:
 168                 ssusb->is_host = false;
 169                 ssusb_set_vbus(otg_sx, 0);
 170                 switch_port_to_device(ssusb);
 171                 break;
 172         case MTU3_VBUS_OFF:
 173                 mtu3_stop(mtu);
 174                 pm_relax(ssusb->dev);
 175                 break;
 176         case MTU3_VBUS_VALID:
 177                 /* avoid suspend when works as device */
 178                 pm_stay_awake(ssusb->dev);
 179                 mtu3_start(mtu);
 180                 break;
 181         default:
 182                 dev_err(ssusb->dev, "invalid state\n");
 183         }
 184 }
 185
 186 static 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         if (event)
 193                 ssusb_set_mailbox(otg_sx, MTU3_ID_GROUND);
 194         else
 195                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 196
 197         return NOTIFY_DONE;
 198 }
 199
 200 static int ssusb_vbus_notifier(struct notifier_block *nb,
 201         unsigned long event, void *ptr)
 202 {
 203         struct otg_switch_mtk *otg_sx =
 204                 container_of(nb, struct otg_switch_mtk, vbus_nb);
 205
 206         if (event)
 207                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 208         else
 209                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_OFF);
 210
 211         return NOTIFY_DONE;
 212 }
 213
 214 static int ssusb_extcon_register(struct otg_switch_mtk *otg_sx)
 215 {
 216         struct ssusb_mtk *ssusb =
 217                 container_of(otg_sx, struct ssusb_mtk, otg_switch);
 218         struct extcon_dev *edev = otg_sx->edev;
 219         int ret;
 220
 221         /* extcon is optional */
 222         if (!edev)
 223                 return 0;
 224
 225         otg_sx->vbus_nb.notifier_call = ssusb_vbus_notifier;
 226         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB,
 227                                         &otg_sx->vbus_nb);
 228         if (ret < 0)
 229                 dev_err(ssusb->dev, "failed to register notifier for USB\n");
 230
 231         otg_sx->id_nb.notifier_call = ssusb_id_notifier;
 232         ret = devm_extcon_register_notifier(ssusb->dev, edev, EXTCON_USB_HOST,
 233                                         &otg_sx->id_nb);
 234         if (ret < 0)
 235                 dev_err(ssusb->dev, "failed to register notifier for USB-HOST\n");
 236
 237         dev_dbg(ssusb->dev, "EXTCON_USB: %d, EXTCON_USB_HOST: %d\n",
 238                 extcon_get_state(edev, EXTCON_USB),
 239                 extcon_get_state(edev, EXTCON_USB_HOST));
 240
 241         /* default as host, switch to device mode if needed */
 242         if (extcon_get_state(edev, EXTCON_USB_HOST) == false)
 243                 ssusb_set_mailbox(otg_sx, MTU3_ID_FLOAT);
 244         if (extcon_get_state(edev, EXTCON_USB) == true)
 245                 ssusb_set_mailbox(otg_sx, MTU3_VBUS_VALID);
 246
 247         return 0;
 248 }
 249
 250 static void extcon_register_dwork(struct work_struct *work)
 251 {
 252         struct delayed_work *dwork = to_delayed_work(work);
 253         struct otg_switch_mtk *otg_sx =
 254             container_of(dwork, struct otg_switch_mtk, extcon_reg_dwork);
 255
 256         ssusb_extcon_register(otg_sx);
 257 }
 258
 259 /*
 260  * We provide an interface via debugfs to switch between host and device modes
 261  * depending on user input.
 262  * This is useful in special cases, such as uses TYPE-A receptacle but also
 263  * wants to support dual-role mode.
 264  * It generates cable state changes by pulling up/down IDPIN and
 265  * notifies driver to switch mode by "extcon-usb-gpio".
 266  * NOTE: when use MICRO receptacle, should not enable this interface.
 267  */
 268 static void ssusb_mode_manual_switch(struct ssusb_mtk *ssusb, int to_host)
 269 {
 270         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 271
 272         if (to_host)
 273                 pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_ground);
 274         else
 275                 pinctrl_select_state(otg_sx->id_pinctrl, otg_sx->id_float);
 276 }
 277
 278
 279 static int ssusb_mode_show(struct seq_file *sf, void *unused)
 280 {
 281         struct ssusb_mtk *ssusb = sf->private;
 282
 283         seq_printf(sf, "current mode: %s(%s drd)\n(echo device/host)\n",
 284                 ssusb->is_host ? "host" : "device",
 285                 ssusb->otg_switch.manual_drd_enabled ? "manual" : "auto");
 286
 287         return 0;
 288 }
 289
 290 static int ssusb_mode_open(struct inode *inode, struct file *file)
 291 {
 292         return single_open(file, ssusb_mode_show, inode->i_private);
 293 }
 294
 295 static ssize_t ssusb_mode_write(struct file *file,
 296         const char __user *ubuf, size_t count, loff_t *ppos)
 297 {
 298         struct seq_file *sf = file->private_data;
 299         struct ssusb_mtk *ssusb = sf->private;
 300         char buf[16];
 301
 302         if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
 303                 return -EFAULT;
 304
 305         if (!strncmp(buf, "host", 4) && !ssusb->is_host) {
 306                 ssusb_mode_manual_switch(ssusb, 1);
 307         } else if (!strncmp(buf, "device", 6) && ssusb->is_host) {
 308                 ssusb_mode_manual_switch(ssusb, 0);
 309         } else {
 310                 dev_err(ssusb->dev, "wrong or duplicated setting\n");
 311                 return -EINVAL;
 312         }
 313
 314         return count;
 315 }
 316
 317 static const struct file_operations ssusb_mode_fops = {
 318         .open = ssusb_mode_open,
 319         .write = ssusb_mode_write,
 320         .read = seq_read,
 321         .llseek = seq_lseek,
 322         .release = single_release,
 323 };
 324
 325 static void ssusb_debugfs_init(struct ssusb_mtk *ssusb)
 326 {
 327         struct dentry *root;
 328         struct dentry *file;
 329
 330         root = debugfs_create_dir(dev_name(ssusb->dev), usb_debug_root);
 331         if (IS_ERR_OR_NULL(root)) {
 332                 if (!root)
 333                         dev_err(ssusb->dev, "create debugfs root failed\n");
 334                 return;
 335         }
 336         ssusb->dbgfs_root = root;
 337
 338         file = debugfs_create_file("mode", S_IRUGO | S_IWUSR, root,
 339                         ssusb, &ssusb_mode_fops);
 340         if (!file)
 341                 dev_dbg(ssusb->dev, "create debugfs mode failed\n");
 342 }
 343
 344 static void ssusb_debugfs_exit(struct ssusb_mtk *ssusb)
 345 {
 346         debugfs_remove_recursive(ssusb->dbgfs_root);
 347 }
 348
 349 int ssusb_otg_switch_init(struct ssusb_mtk *ssusb)
 350 {
 351         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 352
 353         INIT_DELAYED_WORK(&otg_sx->extcon_reg_dwork, extcon_register_dwork);
 354
 355         if (otg_sx->manual_drd_enabled)
 356                 ssusb_debugfs_init(ssusb);
 357
 358         /* It is enough to delay 1s for waiting for host initialization */
 359         schedule_delayed_work(&otg_sx->extcon_reg_dwork, HZ);
 360
 361         return 0;
 362 }
 363
 364 void ssusb_otg_switch_exit(struct ssusb_mtk *ssusb)
 365 {
 366         struct otg_switch_mtk *otg_sx = &ssusb->otg_switch;
 367
 368         cancel_delayed_work(&otg_sx->extcon_reg_dwork);
 369
 370         if (otg_sx->manual_drd_enabled)
 371                 ssusb_debugfs_exit(ssusb);
 372 }