drivers/usb/phy/phy-tahvo.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Tahvo USB transceiver driver
   4  *
   5  * Copyright (C) 2005-2006 Nokia Corporation
   6  *
   7  * Parts copied from isp1301_omap.c.
   8  * Copyright (C) 2004 Texas Instruments
   9  * Copyright (C) 2004 David Brownell
  10  *
  11  * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
  12  * Modified for Retu/Tahvo MFD by Aaro Koskinen.
  13  */
  14
  15 #include <linux/io.h>
  16 #include <linux/clk.h>
  17 #include <linux/usb.h>
  18 #include <linux/extcon-provider.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/string_choices.h>
  22 #include <linux/usb/otg.h>
  23 #include <linux/mfd/retu.h>
  24 #include <linux/usb/gadget.h>
  25 #include <linux/platform_device.h>
  26
  27 #define DRIVER_NAME     "tahvo-usb"
  28
  29 #define TAHVO_REG_IDSR  0x02
  30 #define TAHVO_REG_USBR  0x06
  31
  32 #define USBR_SLAVE_CONTROL      (1 << 8)
  33 #define USBR_VPPVIO_SW          (1 << 7)
  34 #define USBR_SPEED              (1 << 6)
  35 #define USBR_REGOUT             (1 << 5)
  36 #define USBR_MASTER_SW2         (1 << 4)
  37 #define USBR_MASTER_SW1         (1 << 3)
  38 #define USBR_SLAVE_SW           (1 << 2)
  39 #define USBR_NSUSPEND           (1 << 1)
  40 #define USBR_SEMODE             (1 << 0)
  41
  42 #define TAHVO_MODE_HOST         0
  43 #define TAHVO_MODE_PERIPHERAL   1
  44
  45 struct tahvo_usb {
  46         struct platform_device  *pt_dev;
  47         struct usb_phy          phy;
  48         int                     vbus_state;
  49         struct mutex            serialize;
  50         struct clk              *ick;
  51         int                     irq;
  52         int                     tahvo_mode;
  53         struct extcon_dev       *extcon;
  54 };
  55
  56 static const unsigned int tahvo_cable[] = {
  57         EXTCON_USB,
  58         EXTCON_USB_HOST,
  59
  60         EXTCON_NONE,
  61 };
  62
  63 static ssize_t vbus_show(struct device *device,
  64                                struct device_attribute *attr, char *buf)
  65 {
  66         struct tahvo_usb *tu = dev_get_drvdata(device);
  67         return sprintf(buf, "%s\n", str_on_off(tu->vbus_state));
  68 }
  69 static DEVICE_ATTR_RO(vbus);
  70
  71 static void check_vbus_state(struct tahvo_usb *tu)
  72 {
  73         struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
  74         int reg, prev_state;
  75
  76         reg = retu_read(rdev, TAHVO_REG_IDSR);
  77         if (reg & TAHVO_STAT_VBUS) {
  78                 switch (tu->phy.otg->state) {
  79                 case OTG_STATE_B_IDLE:
  80                         /* Enable the gadget driver */
  81                         if (tu->phy.otg->gadget)
  82                                 usb_gadget_vbus_connect(tu->phy.otg->gadget);
  83                         tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
  84                         usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
  85                         break;
  86                 case OTG_STATE_A_IDLE:
  87                         /*
  88                          * Session is now valid assuming the USB hub is driving
  89                          * Vbus.
  90                          */
  91                         tu->phy.otg->state = OTG_STATE_A_HOST;
  92                         break;
  93                 default:
  94                         break;
  95                 }
  96                 dev_info(&tu->pt_dev->dev, "USB cable connected\n");
  97         } else {
  98                 switch (tu->phy.otg->state) {
  99                 case OTG_STATE_B_PERIPHERAL:
 100                         if (tu->phy.otg->gadget)
 101                                 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
 102                         tu->phy.otg->state = OTG_STATE_B_IDLE;
 103                         usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
 104                         break;
 105                 case OTG_STATE_A_HOST:
 106                         tu->phy.otg->state = OTG_STATE_A_IDLE;
 107                         break;
 108                 default:
 109                         break;
 110                 }
 111                 dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
 112         }
 113
 114         prev_state = tu->vbus_state;
 115         tu->vbus_state = reg & TAHVO_STAT_VBUS;
 116         if (prev_state != tu->vbus_state) {
 117                 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
 118                 sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
 119         }
 120 }
 121
 122 static void tahvo_usb_become_host(struct tahvo_usb *tu)
 123 {
 124         struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 125
 126         extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, true);
 127
 128         /* Power up the transceiver in USB host mode */
 129         retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
 130                    USBR_MASTER_SW2 | USBR_MASTER_SW1);
 131         tu->phy.otg->state = OTG_STATE_A_IDLE;
 132
 133         check_vbus_state(tu);
 134 }
 135
 136 static void tahvo_usb_stop_host(struct tahvo_usb *tu)
 137 {
 138         tu->phy.otg->state = OTG_STATE_A_IDLE;
 139 }
 140
 141 static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
 142 {
 143         struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 144
 145         extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, false);
 146
 147         /* Power up transceiver and set it in USB peripheral mode */
 148         retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
 149                    USBR_NSUSPEND | USBR_SLAVE_SW);
 150         tu->phy.otg->state = OTG_STATE_B_IDLE;
 151
 152         check_vbus_state(tu);
 153 }
 154
 155 static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
 156 {
 157         if (tu->phy.otg->gadget)
 158                 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
 159         tu->phy.otg->state = OTG_STATE_B_IDLE;
 160 }
 161
 162 static void tahvo_usb_power_off(struct tahvo_usb *tu)
 163 {
 164         struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 165
 166         /* Disable gadget controller if any */
 167         if (tu->phy.otg->gadget)
 168                 usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
 169
 170         /* Power off transceiver */
 171         retu_write(rdev, TAHVO_REG_USBR, 0);
 172         tu->phy.otg->state = OTG_STATE_UNDEFINED;
 173 }
 174
 175 static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
 176 {
 177         struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
 178         struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 179         u16 w;
 180
 181         dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);
 182
 183         w = retu_read(rdev, TAHVO_REG_USBR);
 184         if (suspend)
 185                 w &= ~USBR_NSUSPEND;
 186         else
 187                 w |= USBR_NSUSPEND;
 188         retu_write(rdev, TAHVO_REG_USBR, w);
 189
 190         return 0;
 191 }
 192
 193 static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
 194 {
 195         struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
 196                                             phy);
 197
 198         mutex_lock(&tu->serialize);
 199
 200         if (host == NULL) {
 201                 if (tu->tahvo_mode == TAHVO_MODE_HOST)
 202                         tahvo_usb_power_off(tu);
 203                 otg->host = NULL;
 204                 mutex_unlock(&tu->serialize);
 205                 return 0;
 206         }
 207
 208         if (tu->tahvo_mode == TAHVO_MODE_HOST) {
 209                 otg->host = NULL;
 210                 tahvo_usb_become_host(tu);
 211         }
 212
 213         otg->host = host;
 214
 215         mutex_unlock(&tu->serialize);
 216
 217         return 0;
 218 }
 219
 220 static int tahvo_usb_set_peripheral(struct usb_otg *otg,
 221                                     struct usb_gadget *gadget)
 222 {
 223         struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
 224                                             phy);
 225
 226         mutex_lock(&tu->serialize);
 227
 228         if (!gadget) {
 229                 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 230                         tahvo_usb_power_off(tu);
 231                 tu->phy.otg->gadget = NULL;
 232                 mutex_unlock(&tu->serialize);
 233                 return 0;
 234         }
 235
 236         tu->phy.otg->gadget = gadget;
 237         if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 238                 tahvo_usb_become_peripheral(tu);
 239
 240         mutex_unlock(&tu->serialize);
 241
 242         return 0;
 243 }
 244
 245 static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
 246 {
 247         struct tahvo_usb *tu = _tu;
 248
 249         mutex_lock(&tu->serialize);
 250         check_vbus_state(tu);
 251         mutex_unlock(&tu->serialize);
 252
 253         return IRQ_HANDLED;
 254 }
 255
 256 static ssize_t otg_mode_show(struct device *device,
 257                              struct device_attribute *attr, char *buf)
 258 {
 259         struct tahvo_usb *tu = dev_get_drvdata(device);
 260
 261         switch (tu->tahvo_mode) {
 262         case TAHVO_MODE_HOST:
 263                 return sprintf(buf, "host\n");
 264         case TAHVO_MODE_PERIPHERAL:
 265                 return sprintf(buf, "peripheral\n");
 266         }
 267
 268         return -EINVAL;
 269 }
 270
 271 static ssize_t otg_mode_store(struct device *device,
 272                               struct device_attribute *attr,
 273                               const char *buf, size_t count)
 274 {
 275         struct tahvo_usb *tu = dev_get_drvdata(device);
 276         int r;
 277
 278         mutex_lock(&tu->serialize);
 279         if (count >= 4 && strncmp(buf, "host", 4) == 0) {
 280                 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 281                         tahvo_usb_stop_peripheral(tu);
 282                 tu->tahvo_mode = TAHVO_MODE_HOST;
 283                 if (tu->phy.otg->host) {
 284                         dev_info(device, "HOST mode: host controller present\n");
 285                         tahvo_usb_become_host(tu);
 286                 } else {
 287                         dev_info(device, "HOST mode: no host controller, powering off\n");
 288                         tahvo_usb_power_off(tu);
 289                 }
 290                 r = strlen(buf);
 291         } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
 292                 if (tu->tahvo_mode == TAHVO_MODE_HOST)
 293                         tahvo_usb_stop_host(tu);
 294                 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
 295                 if (tu->phy.otg->gadget) {
 296                         dev_info(device, "PERIPHERAL mode: gadget driver present\n");
 297                         tahvo_usb_become_peripheral(tu);
 298                 } else {
 299                         dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
 300                         tahvo_usb_power_off(tu);
 301                 }
 302                 r = strlen(buf);
 303         } else {
 304                 r = -EINVAL;
 305         }
 306         mutex_unlock(&tu->serialize);
 307
 308         return r;
 309 }
 310 static DEVICE_ATTR_RW(otg_mode);
 311
 312 static struct attribute *tahvo_attrs[] = {
 313         &dev_attr_vbus.attr,
 314         &dev_attr_otg_mode.attr,
 315         NULL
 316 };
 317 ATTRIBUTE_GROUPS(tahvo);
 318
 319 static int tahvo_usb_probe(struct platform_device *pdev)
 320 {
 321         struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
 322         struct tahvo_usb *tu;
 323         int ret;
 324
 325         tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
 326         if (!tu)
 327                 return -ENOMEM;
 328
 329         tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
 330                                    GFP_KERNEL);
 331         if (!tu->phy.otg)
 332                 return -ENOMEM;
 333
 334         tu->pt_dev = pdev;
 335
 336         /* Default mode */
 337 #ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
 338         tu->tahvo_mode = TAHVO_MODE_HOST;
 339 #else
 340         tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
 341 #endif
 342
 343         mutex_init(&tu->serialize);
 344
 345         tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
 346         if (!IS_ERR(tu->ick))
 347                 clk_enable(tu->ick);
 348
 349         /*
 350          * Set initial state, so that we generate kevents only on state changes.
 351          */
 352         tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;
 353
 354         tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable);
 355         if (IS_ERR(tu->extcon)) {
 356                 dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
 357                 ret = PTR_ERR(tu->extcon);
 358                 goto err_disable_clk;
 359         }
 360
 361         ret = devm_extcon_dev_register(&pdev->dev, tu->extcon);
 362         if (ret) {
 363                 dev_err(&pdev->dev, "could not register extcon device: %d\n",
 364                         ret);
 365                 goto err_disable_clk;
 366         }
 367
 368         /* Set the initial cable state. */
 369         extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST,
 370                                tu->tahvo_mode == TAHVO_MODE_HOST);
 371         extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
 372
 373         /* Create OTG interface */
 374         tahvo_usb_power_off(tu);
 375         tu->phy.dev = &pdev->dev;
 376         tu->phy.otg->state = OTG_STATE_UNDEFINED;
 377         tu->phy.label = DRIVER_NAME;
 378         tu->phy.set_suspend = tahvo_usb_set_suspend;
 379
 380         tu->phy.otg->usb_phy = &tu->phy;
 381         tu->phy.otg->set_host = tahvo_usb_set_host;
 382         tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;
 383
 384         ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
 385         if (ret < 0) {
 386                 dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
 387                         ret);
 388                 goto err_disable_clk;
 389         }
 390
 391         dev_set_drvdata(&pdev->dev, tu);
 392
 393         tu->irq = ret = platform_get_irq(pdev, 0);
 394         if (ret < 0)
 395                 goto err_remove_phy;
 396         ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
 397                                    IRQF_ONESHOT,
 398                                    "tahvo-vbus", tu);
 399         if (ret) {
 400                 dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
 401                         ret);
 402                 goto err_remove_phy;
 403         }
 404
 405         return 0;
 406
 407 err_remove_phy:
 408         usb_remove_phy(&tu->phy);
 409 err_disable_clk:
 410         if (!IS_ERR(tu->ick))
 411                 clk_disable(tu->ick);
 412
 413         return ret;
 414 }
 415
 416 static void tahvo_usb_remove(struct platform_device *pdev)
 417 {
 418         struct tahvo_usb *tu = platform_get_drvdata(pdev);
 419
 420         free_irq(tu->irq, tu);
 421         usb_remove_phy(&tu->phy);
 422         if (!IS_ERR(tu->ick))
 423                 clk_disable(tu->ick);
 424 }
 425
 426 static struct platform_driver tahvo_usb_driver = {
 427         .probe          = tahvo_usb_probe,
 428         .remove         = tahvo_usb_remove,
 429         .driver         = {
 430                 .name   = "tahvo-usb",
 431                 .dev_groups = tahvo_groups,
 432         },
 433 };
 434 module_platform_driver(tahvo_usb_driver);
 435
 436 MODULE_DESCRIPTION("Tahvo USB transceiver driver");
 437 MODULE_LICENSE("GPL");
 438 MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
 439 MODULE_AUTHOR("Aaro Koskinen <[email protected]>");