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 mutex_lock(&tu->serialize); 198 199 if (host == NULL) { 200 if (tu->tahvo_mode == TAHVO_MODE_HOST) 201 tahvo_usb_power_off(tu); 202 otg->host = NULL; 203 mutex_unlock(&tu->serialize); 204 return 0; 205 } 206 207 if (tu->tahvo_mode == TAHVO_MODE_HOST) { 208 otg->host = NULL; 209 tahvo_usb_become_host(tu); 210 } 211 212 otg->host = host; 213 214 mutex_unlock(&tu->serialize); 215 216 return 0; 217 } 218 219 static int tahvo_usb_set_peripheral(struct usb_otg *otg, 220 struct usb_gadget *gadget) 221 { 222 struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb, 223 phy); 224 225 mutex_lock(&tu->serialize); 226 227 if (!gadget) { 228 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 229 tahvo_usb_power_off(tu); 230 tu->phy.otg->gadget = NULL; 231 mutex_unlock(&tu->serialize); 232 return 0; 233 } 234 235 tu->phy.otg->gadget = gadget; 236 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 237 tahvo_usb_become_peripheral(tu); 238 239 mutex_unlock(&tu->serialize); 240 241 return 0; 242 } 243 244 static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu) 245 { 246 struct tahvo_usb *tu = _tu; 247 248 mutex_lock(&tu->serialize); 249 check_vbus_state(tu); 250 mutex_unlock(&tu->serialize); 251 252 return IRQ_HANDLED; 253 } 254 255 static ssize_t otg_mode_show(struct device *device, 256 struct device_attribute *attr, char *buf) 257 { 258 struct tahvo_usb *tu = dev_get_drvdata(device); 259 260 switch (tu->tahvo_mode) { 261 case TAHVO_MODE_HOST: 262 return sprintf(buf, "host\n"); 263 case TAHVO_MODE_PERIPHERAL: 264 return sprintf(buf, "peripheral\n"); 265 } 266 267 return -EINVAL; 268 } 269 270 static ssize_t otg_mode_store(struct device *device, 271 struct device_attribute *attr, 272 const char *buf, size_t count) 273 { 274 struct tahvo_usb *tu = dev_get_drvdata(device); 275 int r; 276 277 mutex_lock(&tu->serialize); 278 if (count >= 4 && strncmp(buf, "host", 4) == 0) { 279 if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL) 280 tahvo_usb_stop_peripheral(tu); 281 tu->tahvo_mode = TAHVO_MODE_HOST; 282 if (tu->phy.otg->host) { 283 dev_info(device, "HOST mode: host controller present\n"); 284 tahvo_usb_become_host(tu); 285 } else { 286 dev_info(device, "HOST mode: no host controller, powering off\n"); 287 tahvo_usb_power_off(tu); 288 } 289 r = strlen(buf); 290 } else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) { 291 if (tu->tahvo_mode == TAHVO_MODE_HOST) 292 tahvo_usb_stop_host(tu); 293 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; 294 if (tu->phy.otg->gadget) { 295 dev_info(device, "PERIPHERAL mode: gadget driver present\n"); 296 tahvo_usb_become_peripheral(tu); 297 } else { 298 dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n"); 299 tahvo_usb_power_off(tu); 300 } 301 r = strlen(buf); 302 } else { 303 r = -EINVAL; 304 } 305 mutex_unlock(&tu->serialize); 306 307 return r; 308 } 309 static DEVICE_ATTR_RW(otg_mode); 310 311 static struct attribute *tahvo_attrs[] = { 312 &dev_attr_vbus.attr, 313 &dev_attr_otg_mode.attr, 314 NULL 315 }; 316 ATTRIBUTE_GROUPS(tahvo); 317 318 static int tahvo_usb_probe(struct platform_device *pdev) 319 { 320 struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent); 321 struct tahvo_usb *tu; 322 int ret; 323 324 tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL); 325 if (!tu) 326 return -ENOMEM; 327 328 tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg), 329 GFP_KERNEL); 330 if (!tu->phy.otg) 331 return -ENOMEM; 332 333 tu->pt_dev = pdev; 334 335 /* Default mode */ 336 #ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT 337 tu->tahvo_mode = TAHVO_MODE_HOST; 338 #else 339 tu->tahvo_mode = TAHVO_MODE_PERIPHERAL; 340 #endif 341 342 mutex_init(&tu->serialize); 343 344 tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick"); 345 if (!IS_ERR(tu->ick)) 346 clk_enable(tu->ick); 347 348 /* 349 * Set initial state, so that we generate kevents only on state changes. 350 */ 351 tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS; 352 353 tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable); 354 if (IS_ERR(tu->extcon)) { 355 dev_err(&pdev->dev, "failed to allocate memory for extcon\n"); 356 ret = PTR_ERR(tu->extcon); 357 goto err_disable_clk; 358 } 359 360 ret = devm_extcon_dev_register(&pdev->dev, tu->extcon); 361 if (ret) { 362 dev_err(&pdev->dev, "could not register extcon device: %d\n", 363 ret); 364 goto err_disable_clk; 365 } 366 367 /* Set the initial cable state. */ 368 extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, 369 tu->tahvo_mode == TAHVO_MODE_HOST); 370 extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state); 371 372 /* Create OTG interface */ 373 tahvo_usb_power_off(tu); 374 tu->phy.dev = &pdev->dev; 375 tu->phy.otg->state = OTG_STATE_UNDEFINED; 376 tu->phy.label = DRIVER_NAME; 377 tu->phy.set_suspend = tahvo_usb_set_suspend; 378 379 tu->phy.otg->usb_phy = &tu->phy; 380 tu->phy.otg->set_host = tahvo_usb_set_host; 381 tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral; 382 383 ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2); 384 if (ret < 0) { 385 dev_err(&pdev->dev, "cannot register USB transceiver: %d\n", 386 ret); 387 goto err_disable_clk; 388 } 389 390 dev_set_drvdata(&pdev->dev, tu); 391 392 tu->irq = ret = platform_get_irq(pdev, 0); 393 if (ret < 0) 394 return ret; 395 ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt, 396 IRQF_ONESHOT, 397 "tahvo-vbus", tu); 398 if (ret) { 399 dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n", 400 ret); 401 goto err_remove_phy; 402 } 403 404 return 0; 405 406 err_remove_phy: 407 usb_remove_phy(&tu->phy); 408 err_disable_clk: 409 if (!IS_ERR(tu->ick)) 410 clk_disable(tu->ick); 411 412 return ret; 413 } 414 415 static void tahvo_usb_remove(struct platform_device *pdev) 416 { 417 struct tahvo_usb *tu = platform_get_drvdata(pdev); 418 419 free_irq(tu->irq, tu); 420 usb_remove_phy(&tu->phy); 421 if (!IS_ERR(tu->ick)) 422 clk_disable(tu->ick); 423 } 424 425 static struct platform_driver tahvo_usb_driver = { 426 .probe = tahvo_usb_probe, 427 .remove_new = tahvo_usb_remove, 428 .driver = { 429 .name = "tahvo-usb", 430 .dev_groups = tahvo_groups, 431 }, 432 }; 433 module_platform_driver(tahvo_usb_driver); 434 435 MODULE_DESCRIPTION("Tahvo USB transceiver driver"); 436 MODULE_LICENSE("GPL"); 437 MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs"); 438 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>"); 439