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/usb/otg.h> 22 #include <linux/mfd/retu.h> 23 #include <linux/usb/gadget.h> 24 #include <linux/platform_device.h> 25 26 #define DRIVER_NAME "tahvo-usb" 27 28 #define TAHVO_REG_IDSR 0x02 29 #define TAHVO_REG_USBR 0x06 30 31 #define USBR_SLAVE_CONTROL (1 << 8) 32 #define USBR_VPPVIO_SW (1 << 7) 33 #define USBR_SPEED (1 << 6) 34 #define USBR_REGOUT (1 << 5) 35 #define USBR_MASTER_SW2 (1 << 4) 36 #define USBR_MASTER_SW1 (1 << 3) 37 #define USBR_SLAVE_SW (1 << 2) 38 #define USBR_NSUSPEND (1 << 1) 39 #define USBR_SEMODE (1 << 0) 40 41 #define TAHVO_MODE_HOST 0 42 #define TAHVO_MODE_PERIPHERAL 1 43 44 struct tahvo_usb { 45 struct platform_device *pt_dev; 46 struct usb_phy phy; 47 int vbus_state; 48 struct mutex serialize; 49 struct clk *ick; 50 int irq; 51 int tahvo_mode; 52 struct extcon_dev *extcon; 53 }; 54 55 static const unsigned int tahvo_cable[] = { 56 EXTCON_USB, 57 EXTCON_USB_HOST, 58 59 EXTCON_NONE, 60 }; 61 62 static ssize_t vbus_show(struct device *device, 63 struct device_attribute *attr, char *buf) 64 { 65 struct tahvo_usb *tu = dev_get_drvdata(device); 66 return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off"); 67 } 68 static DEVICE_ATTR_RO(vbus); 69 70 static void check_vbus_state(struct tahvo_usb *tu) 71 { 72 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); 73 int reg, prev_state; 74 75 reg = retu_read(rdev, TAHVO_REG_IDSR); 76 if (reg & TAHVO_STAT_VBUS) { 77 switch (tu->phy.otg->state) { 78 case OTG_STATE_B_IDLE: 79 /* Enable the gadget driver */ 80 if (tu->phy.otg->gadget) 81 usb_gadget_vbus_connect(tu->phy.otg->gadget); 82 tu->phy.otg->state = OTG_STATE_B_PERIPHERAL; 83 usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED); 84 break; 85 case OTG_STATE_A_IDLE: 86 /* 87 * Session is now valid assuming the USB hub is driving 88 * Vbus. 89 */ 90 tu->phy.otg->state = OTG_STATE_A_HOST; 91 break; 92 default: 93 break; 94 } 95 dev_info(&tu->pt_dev->dev, "USB cable connected\n"); 96 } else { 97 switch (tu->phy.otg->state) { 98 case OTG_STATE_B_PERIPHERAL: 99 if (tu->phy.otg->gadget) 100 usb_gadget_vbus_disconnect(tu->phy.otg->gadget); 101 tu->phy.otg->state = OTG_STATE_B_IDLE; 102 usb_phy_set_event(&tu->phy, USB_EVENT_NONE); 103 break; 104 case OTG_STATE_A_HOST: 105 tu->phy.otg->state = OTG_STATE_A_IDLE; 106 break; 107 default: 108 break; 109 } 110 dev_info(&tu->pt_dev->dev, "USB cable disconnected\n"); 111 } 112 113 prev_state = tu->vbus_state; 114 tu->vbus_state = reg & TAHVO_STAT_VBUS; 115 if (prev_state != tu->vbus_state) { 116 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state); 117 sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state"); 118 } 119 } 120 121 static void tahvo_usb_become_host(struct tahvo_usb *tu) 122 { 123 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); 124 125 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, true); 126 127 /* Power up the transceiver in USB host mode */ 128 retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND | 129 USBR_MASTER_SW2 | USBR_MASTER_SW1); 130 tu->phy.otg->state = OTG_STATE_A_IDLE; 131 132 check_vbus_state(tu); 133 } 134 135 static void tahvo_usb_stop_host(struct tahvo_usb *tu) 136 { 137 tu->phy.otg->state = OTG_STATE_A_IDLE; 138 } 139 140 static void tahvo_usb_become_peripheral(struct tahvo_usb *tu) 141 { 142 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); 143 144 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, false); 145 146 /* Power up transceiver and set it in USB peripheral mode */ 147 retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT | 148 USBR_NSUSPEND | USBR_SLAVE_SW); 149 tu->phy.otg->state = OTG_STATE_B_IDLE; 150 151 check_vbus_state(tu); 152 } 153 154 static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu) 155 { 156 if (tu->phy.otg->gadget) 157 usb_gadget_vbus_disconnect(tu->phy.otg->gadget); 158 tu->phy.otg->state = OTG_STATE_B_IDLE; 159 } 160 161 static void tahvo_usb_power_off(struct tahvo_usb *tu) 162 { 163 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); 164 165 /* Disable gadget controller if any */ 166 if (tu->phy.otg->gadget) 167 usb_gadget_vbus_disconnect(tu->phy.otg->gadget); 168 169 /* Power off transceiver */ 170 retu_write(rdev, TAHVO_REG_USBR, 0); 171 tu->phy.otg->state = OTG_STATE_UNDEFINED; 172 } 173 174 static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend) 175 { 176 struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy); 177 struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent); 178 u16 w; 179 180 dev_dbg(&tu->pt_dev->dev, "%s\n", __func__); 181 182 w = retu_read(rdev, TAHVO_REG_USBR); 183 if (suspend) 184 w &= ~USBR_NSUSPEND; 185 else 186 w |= USBR_NSUSPEND; 187 retu_write(rdev, TAHVO_REG_USBR, w); 188 189 return 0; 190 } 191 192 static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host) 193 { 194 struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb, 195 phy); 196 197 dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host); 198 199 mutex_lock(&tu->serialize); 200 201 if (host == NULL) { 202 if (tu->tahvo_mode == TAHVO_MODE_HOST) 203 tahvo_usb_power_off(tu); 204 otg->host = NULL; 205 mutex_unlock(&tu->serialize); 206 return 0; 207 } 208 209 if (tu->tahvo_mode == TAHVO_MODE_HOST) { 210 otg->host = NULL; 211 tahvo_usb_become_host(tu); 212 } 213 214 otg->host = host; 215 216 mutex_unlock(&tu->serialize); 217 218 return 0; 219 } 220 221 static int tahvo_usb_set_peripheral(struct usb_otg *otg, 222 struct usb_gadget *gadget) 223 { 224 struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb, 225 phy); 226 227 dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget); 228 229 mutex_lock(&tu->serialize); 230 231 if (!gadget) { 232 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 233 tahvo_usb_power_off(tu); 234 tu->phy.otg->gadget = NULL; 235 mutex_unlock(&tu->serialize); 236 return 0; 237 } 238 239 tu->phy.otg->gadget = gadget; 240 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 241 tahvo_usb_become_peripheral(tu); 242 243 mutex_unlock(&tu->serialize); 244 245 return 0; 246 } 247 248 static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu) 249 { 250 struct tahvo_usb *tu = _tu; 251 252 mutex_lock(&tu->serialize); 253 check_vbus_state(tu); 254 mutex_unlock(&tu->serialize); 255 256 return IRQ_HANDLED; 257 } 258 259 static ssize_t otg_mode_show(struct device *device, 260 struct device_attribute *attr, char *buf) 261 { 262 struct tahvo_usb *tu = dev_get_drvdata(device); 263 264 switch (tu->tahvo_mode) { 265 case TAHVO_MODE_HOST: 266 return sprintf(buf, "host\n"); 267 case TAHVO_MODE_PERIPHERAL: 268 return sprintf(buf, "peripheral\n"); 269 } 270 271 return -EINVAL; 272 } 273 274 static ssize_t otg_mode_store(struct device *device, 275 struct device_attribute *attr, 276 const char *buf, size_t count) 277 { 278 struct tahvo_usb *tu = dev_get_drvdata(device); 279 int r; 280 281 mutex_lock(&tu->serialize); 282 if (count >= 4 && strncmp(buf, "host", 4) == 0) { 283 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 284 tahvo_usb_stop_peripheral(tu); 285 tu->tahvo_mode = TAHVO_MODE_HOST; 286 if (tu->phy.otg->host) { 287 dev_info(device, "HOST mode: host controller present\n"); 288 tahvo_usb_become_host(tu); 289 } else { 290 dev_info(device, "HOST mode: no host controller, powering off\n"); 291 tahvo_usb_power_off(tu); 292 } 293 r = strlen(buf); 294 } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) { 295 if (tu->tahvo_mode == TAHVO_MODE_HOST) 296 tahvo_usb_stop_host(tu); 297 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; 298 if (tu->phy.otg->gadget) { 299 dev_info(device, "PERIPHERAL mode: gadget driver present\n"); 300 tahvo_usb_become_peripheral(tu); 301 } else { 302 dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n"); 303 tahvo_usb_power_off(tu); 304 } 305 r = strlen(buf); 306 } else { 307 r = -EINVAL; 308 } 309 mutex_unlock(&tu->serialize); 310 311 return r; 312 } 313 static DEVICE_ATTR_RW(otg_mode); 314 315 static struct attribute *tahvo_attrs[] = { 316 &dev_attr_vbus.attr, 317 &dev_attr_otg_mode.attr, 318 NULL 319 }; 320 ATTRIBUTE_GROUPS(tahvo); 321 322 static int tahvo_usb_probe(struct platform_device *pdev) 323 { 324 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent); 325 struct tahvo_usb *tu; 326 int ret; 327 328 tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL); 329 if (!tu) 330 return -ENOMEM; 331 332 tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg), 333 GFP_KERNEL); 334 if (!tu->phy.otg) 335 return -ENOMEM; 336 337 tu->pt_dev = pdev; 338 339 /* Default mode */ 340 #ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT 341 tu->tahvo_mode = TAHVO_MODE_HOST; 342 #else 343 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; 344 #endif 345 346 mutex_init(&tu->serialize); 347 348 tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick"); 349 if (!IS_ERR(tu->ick)) 350 clk_enable(tu->ick); 351 352 /* 353 * Set initial state, so that we generate kevents only on state changes. 354 */ 355 tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS; 356 357 tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable); 358 if (IS_ERR(tu->extcon)) { 359 dev_err(&pdev->dev, "failed to allocate memory for extcon\n"); 360 ret = PTR_ERR(tu->extcon); 361 goto err_disable_clk; 362 } 363 364 ret = devm_extcon_dev_register(&pdev->dev, tu->extcon); 365 if (ret) { 366 dev_err(&pdev->dev, "could not register extcon device: %d\n", 367 ret); 368 goto err_disable_clk; 369 } 370 371 /* Set the initial cable state. */ 372 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, 373 tu->tahvo_mode == TAHVO_MODE_HOST); 374 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state); 375 376 /* Create OTG interface */ 377 tahvo_usb_power_off(tu); 378 tu->phy.dev = &pdev->dev; 379 tu->phy.otg->state = OTG_STATE_UNDEFINED; 380 tu->phy.label = DRIVER_NAME; 381 tu->phy.set_suspend = tahvo_usb_set_suspend; 382 383 tu->phy.otg->usb_phy = &tu->phy; 384 tu->phy.otg->set_host = tahvo_usb_set_host; 385 tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral; 386 387 ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2); 388 if (ret < 0) { 389 dev_err(&pdev->dev, "cannot register USB transceiver: %d\n", 390 ret); 391 goto err_disable_clk; 392 } 393 394 dev_set_drvdata(&pdev->dev, tu); 395 396 tu->irq = platform_get_irq(pdev, 0); 397 ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt, 398 IRQF_ONESHOT, 399 "tahvo-vbus", tu); 400 if (ret) { 401 dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n", 402 ret); 403 goto err_remove_phy; 404 } 405 406 return 0; 407 408 err_remove_phy: 409 usb_remove_phy(&tu->phy); 410 err_disable_clk: 411 if (!IS_ERR(tu->ick)) 412 clk_disable(tu->ick); 413 414 return ret; 415 } 416 417 static int tahvo_usb_remove(struct platform_device *pdev) 418 { 419 struct tahvo_usb *tu = platform_get_drvdata(pdev); 420 421 free_irq(tu->irq, tu); 422 usb_remove_phy(&tu->phy); 423 if (!IS_ERR(tu->ick)) 424 clk_disable(tu->ick); 425 426 return 0; 427 } 428 429 static struct platform_driver tahvo_usb_driver = { 430 .probe = tahvo_usb_probe, 431 .remove = tahvo_usb_remove, 432 .driver = { 433 .name = "tahvo-usb", 434 .dev_groups = tahvo_groups, 435 }, 436 }; 437 module_platform_driver(tahvo_usb_driver); 438 439 MODULE_DESCRIPTION("Tahvo USB transceiver driver"); 440 MODULE_LICENSE("GPL"); 441 MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs"); 442 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>"); 443