drivers/tty/serial/8250/8250_pnp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Probe for 8250/16550-type ISAPNP serial ports.
   4  *
   5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6  *
   7  *  Copyright (C) 2001 Russell King, All Rights Reserved.
   8  *
   9  *  Ported to the Linux PnP Layer - (C) Adam Belay.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/pci.h>
  13 #include <linux/pnp.h>
  14 #include <linux/string.h>
  15 #include <linux/kernel.h>
  16 #include <linux/serial_core.h>
  17 #include <linux/bitops.h>
  18
  19 #include <asm/byteorder.h>
  20
  21 #include "8250.h"
  22
  23 #define UNKNOWN_DEV 0x3000
  24 #define CIR_PORT        0x0800
  25
  26 static const struct pnp_device_id pnp_dev_table[] = {
  27         /* Archtek America Corp. */
  28         /* Archtek SmartLink Modem 3334BT Plug & Play */
  29         {       "AAC000F",              0       },
  30         /* Anchor Datacomm BV */
  31         /* SXPro 144 External Data Fax Modem Plug & Play */
  32         {       "ADC0001",              0       },
  33         /* SXPro 288 External Data Fax Modem Plug & Play */
  34         {       "ADC0002",              0       },
  35         /* PROLiNK 1456VH ISA PnP K56flex Fax Modem */
  36         {       "AEI0250",              0       },
  37         /* Actiontec ISA PNP 56K X2 Fax Modem */
  38         {       "AEI1240",              0       },
  39         /* Rockwell 56K ACF II Fax+Data+Voice Modem */
  40         {       "AKY1021",              0 /*SPCI_FL_NO_SHIRQ*/  },
  41         /*
  42          * ALi Fast Infrared Controller
  43          * Native driver (ali-ircc) is broken so at least
  44          * it can be used with irtty-sir.
  45          */
  46         {       "ALI5123",              0       },
  47         /* AZT3005 PnP SOUND DEVICE */
  48         {       "AZT4001",              0       },
  49         /* Best Data Products Inc. Smart One 336F PnP Modem */
  50         {       "BDP3336",              0       },
  51         /*  Boca Research */
  52         /* Boca Complete Ofc Communicator 14.4 Data-FAX */
  53         {       "BRI0A49",              0       },
  54         /* Boca Research 33,600 ACF Modem */
  55         {       "BRI1400",              0       },
  56         /* Boca 33.6 Kbps Internal FD34FSVD */
  57         {       "BRI3400",              0       },
  58         /* Boca 33.6 Kbps Internal FD34FSVD */
  59         {       "BRI0A49",              0       },
  60         /* Best Data Products Inc. Smart One 336F PnP Modem */
  61         {       "BDP3336",              0       },
  62         /* Computer Peripherals Inc */
  63         /* EuroViVa CommCenter-33.6 SP PnP */
  64         {       "CPI4050",              0       },
  65         /* Creative Labs */
  66         /* Creative Labs Phone Blaster 28.8 DSVD PnP Voice */
  67         {       "CTL3001",              0       },
  68         /* Creative Labs Modem Blaster 28.8 DSVD PnP Voice */
  69         {       "CTL3011",              0       },
  70         /* Davicom ISA 33.6K Modem */
  71         {       "DAV0336",              0       },
  72         /* Creative */
  73         /* Creative Modem Blaster Flash56 DI5601-1 */
  74         {       "DMB1032",              0       },
  75         /* Creative Modem Blaster V.90 DI5660 */
  76         {       "DMB2001",              0       },
  77         /* E-Tech */
  78         /* E-Tech CyberBULLET PC56RVP */
  79         {       "ETT0002",              0       },
  80         /* FUJITSU */
  81         /* Fujitsu 33600 PnP-I2 R Plug & Play */
  82         {       "FUJ0202",              0       },
  83         /* Fujitsu FMV-FX431 Plug & Play */
  84         {       "FUJ0205",              0       },
  85         /* Fujitsu 33600 PnP-I4 R Plug & Play */
  86         {       "FUJ0206",              0       },
  87         /* Fujitsu Fax Voice 33600 PNP-I5 R Plug & Play */
  88         {       "FUJ0209",              0       },
  89         /* Archtek America Corp. */
  90         /* Archtek SmartLink Modem 3334BT Plug & Play */
  91         {       "GVC000F",              0       },
  92         /* Archtek SmartLink Modem 3334BRV 33.6K Data Fax Voice */
  93         {       "GVC0303",              0       },
  94         /* Hayes */
  95         /* Hayes Optima 288 V.34-V.FC + FAX + Voice Plug & Play */
  96         {       "HAY0001",              0       },
  97         /* Hayes Optima 336 V.34 + FAX + Voice PnP */
  98         {       "HAY000C",              0       },
  99         /* Hayes Optima 336B V.34 + FAX + Voice PnP */
 100         {       "HAY000D",              0       },
 101         /* Hayes Accura 56K Ext Fax Modem PnP */
 102         {       "HAY5670",              0       },
 103         /* Hayes Accura 56K Ext Fax Modem PnP */
 104         {       "HAY5674",              0       },
 105         /* Hayes Accura 56K Fax Modem PnP */
 106         {       "HAY5675",              0       },
 107         /* Hayes 288, V.34 + FAX */
 108         {       "HAYF000",              0       },
 109         /* Hayes Optima 288 V.34 + FAX + Voice, Plug & Play */
 110         {       "HAYF001",              0       },
 111         /* IBM */
 112         /* IBM Thinkpad 701 Internal Modem Voice */
 113         {       "IBM0033",              0       },
 114         /* Intermec */
 115         /* Intermec CV60 touchscreen port */
 116         {       "PNP4972",              0       },
 117         /* Intertex */
 118         /* Intertex 28k8 33k6 Voice EXT PnP */
 119         {       "IXDC801",              0       },
 120         /* Intertex 33k6 56k Voice EXT PnP */
 121         {       "IXDC901",              0       },
 122         /* Intertex 28k8 33k6 Voice SP EXT PnP */
 123         {       "IXDD801",              0       },
 124         /* Intertex 33k6 56k Voice SP EXT PnP */
 125         {       "IXDD901",              0       },
 126         /* Intertex 28k8 33k6 Voice SP INT PnP */
 127         {       "IXDF401",              0       },
 128         /* Intertex 28k8 33k6 Voice SP EXT PnP */
 129         {       "IXDF801",              0       },
 130         /* Intertex 33k6 56k Voice SP EXT PnP */
 131         {       "IXDF901",              0       },
 132         /* Kortex International */
 133         /* KORTEX 28800 Externe PnP */
 134         {       "KOR4522",              0       },
 135         /* KXPro 33.6 Vocal ASVD PnP */
 136         {       "KORF661",              0       },
 137         /* Lasat */
 138         /* LASAT Internet 33600 PnP */
 139         {       "LAS4040",              0       },
 140         /* Lasat Safire 560 PnP */
 141         {       "LAS4540",              0       },
 142         /* Lasat Safire 336  PnP */
 143         {       "LAS5440",              0       },
 144         /* Microcom, Inc. */
 145         /* Microcom TravelPorte FAST V.34 Plug & Play */
 146         {       "MNP0281",              0       },
 147         /* Microcom DeskPorte V.34 FAST or FAST+ Plug & Play */
 148         {       "MNP0336",              0       },
 149         /* Microcom DeskPorte FAST EP 28.8 Plug & Play */
 150         {       "MNP0339",              0       },
 151         /* Microcom DeskPorte 28.8P Plug & Play */
 152         {       "MNP0342",              0       },
 153         /* Microcom DeskPorte FAST ES 28.8 Plug & Play */
 154         {       "MNP0500",              0       },
 155         /* Microcom DeskPorte FAST ES 28.8 Plug & Play */
 156         {       "MNP0501",              0       },
 157         /* Microcom DeskPorte 28.8S Internal Plug & Play */
 158         {       "MNP0502",              0       },
 159         /* Motorola */
 160         /* Motorola BitSURFR Plug & Play */
 161         {       "MOT1105",              0       },
 162         /* Motorola TA210 Plug & Play */
 163         {       "MOT1111",              0       },
 164         /* Motorola HMTA 200 (ISDN) Plug & Play */
 165         {       "MOT1114",              0       },
 166         /* Motorola BitSURFR Plug & Play */
 167         {       "MOT1115",              0       },
 168         /* Motorola Lifestyle 28.8 Internal */
 169         {       "MOT1190",              0       },
 170         /* Motorola V.3400 Plug & Play */
 171         {       "MOT1501",              0       },
 172         /* Motorola Lifestyle 28.8 V.34 Plug & Play */
 173         {       "MOT1502",              0       },
 174         /* Motorola Power 28.8 V.34 Plug & Play */
 175         {       "MOT1505",              0       },
 176         /* Motorola ModemSURFR External 28.8 Plug & Play */
 177         {       "MOT1509",              0       },
 178         /* Motorola Premier 33.6 Desktop Plug & Play */
 179         {       "MOT150A",              0       },
 180         /* Motorola VoiceSURFR 56K External PnP */
 181         {       "MOT150F",              0       },
 182         /* Motorola ModemSURFR 56K External PnP */
 183         {       "MOT1510",              0       },
 184         /* Motorola ModemSURFR 56K Internal PnP */
 185         {       "MOT1550",              0       },
 186         /* Motorola ModemSURFR Internal 28.8 Plug & Play */
 187         {       "MOT1560",              0       },
 188         /* Motorola Premier 33.6 Internal Plug & Play */
 189         {       "MOT1580",              0       },
 190         /* Motorola OnlineSURFR 28.8 Internal Plug & Play */
 191         {       "MOT15B0",              0       },
 192         /* Motorola VoiceSURFR 56K Internal PnP */
 193         {       "MOT15F0",              0       },
 194         /* Com 1 */
 195         /*  Deskline K56 Phone System PnP */
 196         {       "MVX00A1",              0       },
 197         /* PC Rider K56 Phone System PnP */
 198         {       "MVX00F2",              0       },
 199         /* NEC 98NOTE SPEAKER PHONE FAX MODEM(33600bps) */
 200         {       "nEC8241",              0       },
 201         /* Pace 56 Voice Internal Plug & Play Modem */
 202         {       "PMC2430",              0       },
 203         /* Generic */
 204         /* Generic standard PC COM port  */
 205         {       "PNP0500",              0       },
 206         /* Generic 16550A-compatible COM port */
 207         {       "PNP0501",              0       },
 208         /* Compaq 14400 Modem */
 209         {       "PNPC000",              0       },
 210         /* Compaq 2400/9600 Modem */
 211         {       "PNPC001",              0       },
 212         /* Dial-Up Networking Serial Cable between 2 PCs */
 213         {       "PNPC031",              0       },
 214         /* Dial-Up Networking Parallel Cable between 2 PCs */
 215         {       "PNPC032",              0       },
 216         /* Standard 9600 bps Modem */
 217         {       "PNPC100",              0       },
 218         /* Standard 14400 bps Modem */
 219         {       "PNPC101",              0       },
 220         /*  Standard 28800 bps Modem*/
 221         {       "PNPC102",              0       },
 222         /*  Standard Modem*/
 223         {       "PNPC103",              0       },
 224         /*  Standard 9600 bps Modem*/
 225         {       "PNPC104",              0       },
 226         /*  Standard 14400 bps Modem*/
 227         {       "PNPC105",              0       },
 228         /*  Standard 28800 bps Modem*/
 229         {       "PNPC106",              0       },
 230         /*  Standard Modem */
 231         {       "PNPC107",              0       },
 232         /* Standard 9600 bps Modem */
 233         {       "PNPC108",              0       },
 234         /* Standard 14400 bps Modem */
 235         {       "PNPC109",              0       },
 236         /* Standard 28800 bps Modem */
 237         {       "PNPC10A",              0       },
 238         /* Standard Modem */
 239         {       "PNPC10B",              0       },
 240         /* Standard 9600 bps Modem */
 241         {       "PNPC10C",              0       },
 242         /* Standard 14400 bps Modem */
 243         {       "PNPC10D",              0       },
 244         /* Standard 28800 bps Modem */
 245         {       "PNPC10E",              0       },
 246         /* Standard Modem */
 247         {       "PNPC10F",              0       },
 248         /* Standard PCMCIA Card Modem */
 249         {       "PNP2000",              0       },
 250         /* Rockwell */
 251         /* Modular Technology */
 252         /* Rockwell 33.6 DPF Internal PnP */
 253         /* Modular Technology 33.6 Internal PnP */
 254         {       "ROK0030",              0       },
 255         /* Kortex International */
 256         /* KORTEX 14400 Externe PnP */
 257         {       "ROK0100",              0       },
 258         /* Rockwell 28.8 */
 259         {       "ROK4120",              0       },
 260         /* Viking Components, Inc */
 261         /* Viking 28.8 INTERNAL Fax+Data+Voice PnP */
 262         {       "ROK4920",              0       },
 263         /* Rockwell */
 264         /* British Telecom */
 265         /* Modular Technology */
 266         /* Rockwell 33.6 DPF External PnP */
 267         /* BT Prologue 33.6 External PnP */
 268         /* Modular Technology 33.6 External PnP */
 269         {       "RSS00A0",              0       },
 270         /* Viking 56K FAX INT */
 271         {       "RSS0262",              0       },
 272         /* K56 par,VV,Voice,Speakphone,AudioSpan,PnP */
 273         {       "RSS0250",              0       },
 274         /* SupraExpress 28.8 Data/Fax PnP modem */
 275         {       "SUP1310",              0       },
 276         /* SupraExpress 336i PnP Voice Modem */
 277         {       "SUP1381",              0       },
 278         /* SupraExpress 33.6 Data/Fax PnP modem */
 279         {       "SUP1421",              0       },
 280         /* SupraExpress 33.6 Data/Fax PnP modem */
 281         {       "SUP1590",              0       },
 282         /* SupraExpress 336i Sp ASVD */
 283         {       "SUP1620",              0       },
 284         /* SupraExpress 33.6 Data/Fax PnP modem */
 285         {       "SUP1760",              0       },
 286         /* SupraExpress 56i Sp Intl */
 287         {       "SUP2171",              0       },
 288         /* Phoebe Micro */
 289         /* Phoebe Micro 33.6 Data Fax 1433VQH Plug & Play */
 290         {       "TEX0011",              0       },
 291         /* Archtek America Corp. */
 292         /* Archtek SmartLink Modem 3334BT Plug & Play */
 293         {       "UAC000F",              0       },
 294         /* 3Com Corp. */
 295         /* Gateway Telepath IIvi 33.6 */
 296         {       "USR0000",              0       },
 297         /* U.S. Robotics Sporster 33.6K Fax INT PnP */
 298         {       "USR0002",              0       },
 299         /*  Sportster Vi 14.4 PnP FAX Voicemail */
 300         {       "USR0004",              0       },
 301         /* U.S. Robotics 33.6K Voice INT PnP */
 302         {       "USR0006",              0       },
 303         /* U.S. Robotics 33.6K Voice EXT PnP */
 304         {       "USR0007",              0       },
 305         /* U.S. Robotics Courier V.Everything INT PnP */
 306         {       "USR0009",              0       },
 307         /* U.S. Robotics 33.6K Voice INT PnP */
 308         {       "USR2002",              0       },
 309         /* U.S. Robotics 56K Voice INT PnP */
 310         {       "USR2070",              0       },
 311         /* U.S. Robotics 56K Voice EXT PnP */
 312         {       "USR2080",              0       },
 313         /* U.S. Robotics 56K FAX INT */
 314         {       "USR3031",              0       },
 315         /* U.S. Robotics 56K FAX INT */
 316         {       "USR3050",              0       },
 317         /* U.S. Robotics 56K Voice INT PnP */
 318         {       "USR3070",              0       },
 319         /* U.S. Robotics 56K Voice EXT PnP */
 320         {       "USR3080",              0       },
 321         /* U.S. Robotics 56K Voice INT PnP */
 322         {       "USR3090",              0       },
 323         /* U.S. Robotics 56K Message  */
 324         {       "USR9100",              0       },
 325         /* U.S. Robotics 56K FAX EXT PnP*/
 326         {       "USR9160",              0       },
 327         /* U.S. Robotics 56K FAX INT PnP*/
 328         {       "USR9170",              0       },
 329         /* U.S. Robotics 56K Voice EXT PnP*/
 330         {       "USR9180",              0       },
 331         /* U.S. Robotics 56K Voice INT PnP*/
 332         {       "USR9190",              0       },
 333         /* Wacom tablets */
 334         {       "WACFXXX",              0       },
 335         /* Compaq touchscreen */
 336         {       "FPI2002",              0 },
 337         /* Fujitsu Stylistic touchscreens */
 338         {       "FUJ02B2",              0 },
 339         {       "FUJ02B3",              0 },
 340         /* Fujitsu Stylistic LT touchscreens */
 341         {       "FUJ02B4",              0 },
 342         /* Passive Fujitsu Stylistic touchscreens */
 343         {       "FUJ02B6",              0 },
 344         {       "FUJ02B7",              0 },
 345         {       "FUJ02B8",              0 },
 346         {       "FUJ02B9",              0 },
 347         {       "FUJ02BC",              0 },
 348         /* Fujitsu Wacom Tablet PC device */
 349         {       "FUJ02E5",              0       },
 350         /* Fujitsu P-series tablet PC device */
 351         {       "FUJ02E6",              0       },
 352         /* Fujitsu Wacom 2FGT Tablet PC device */
 353         {       "FUJ02E7",              0       },
 354         /* Fujitsu Wacom 1FGT Tablet PC device */
 355         {       "FUJ02E9",              0       },
 356         /*
 357          * LG C1 EXPRESS DUAL (C1-PB11A3) touch screen (actually a FUJ02E6
 358          * in disguise).
 359          */
 360         {       "LTS0001",              0       },
 361         /* Rockwell's (PORALiNK) 33600 INT PNP */
 362         {       "WCI0003",              0       },
 363         /* Unknown PnP modems */
 364         {       "PNPCXXX",              UNKNOWN_DEV     },
 365         /* More unknown PnP modems */
 366         {       "PNPDXXX",              UNKNOWN_DEV     },
 367         /*
 368          * Winbond CIR port, should not be probed. We should keep track of
 369          * it to prevent the legacy serial driver from probing it.
 370          */
 371         {       "WEC1022",              CIR_PORT        },
 372         /*
 373          * SMSC IrCC SIR/FIR port, should not be probed by serial driver as
 374          * well so its own driver can bind to it.
 375          */
 376         {       "SMCF010",              CIR_PORT        },
 377         {       "",                     0       }
 378 };
 379
 380 MODULE_DEVICE_TABLE(pnp, pnp_dev_table);
 381
 382 static const char *modem_names[] = {
 383         "MODEM", "Modem", "modem", "FAX", "Fax", "fax",
 384         "56K", "56k", "K56", "33.6", "28.8", "14.4",
 385         "33,600", "28,800", "14,400", "33.600", "28.800", "14.400",
 386         "33600", "28800", "14400", "V.90", "V.34", "V.32", NULL
 387 };
 388
 389 static bool check_name(const char *name)
 390 {
 391         const char **tmp;
 392
 393         for (tmp = modem_names; *tmp; tmp++)
 394                 if (strstr(name, *tmp))
 395                         return true;
 396
 397         return false;
 398 }
 399
 400 static bool check_resources(struct pnp_dev *dev)
 401 {
 402         static const resource_size_t base[] = {0x2f8, 0x3f8, 0x2e8, 0x3e8};
 403         unsigned int i;
 404
 405         for (i = 0; i < ARRAY_SIZE(base); i++) {
 406                 if (pnp_possible_config(dev, IORESOURCE_IO, base[i], 8))
 407                         return true;
 408         }
 409
 410         return false;
 411 }
 412
 413 /*
 414  * Given a complete unknown PnP device, try to use some heuristics to
 415  * detect modems. Currently use such heuristic set:
 416  *     - dev->name or dev->bus->name must contain "modem" substring;
 417  *     - device must have only one IO region (8 byte long) with base address
 418  *       0x2e8, 0x3e8, 0x2f8 or 0x3f8.
 419  *
 420  * Such detection looks very ugly, but can detect at least some of numerous
 421  * PnP modems, alternatively we must hardcode all modems in pnp_devices[]
 422  * table.
 423  */
 424 static int serial_pnp_guess_board(struct pnp_dev *dev)
 425 {
 426         if (!(check_name(pnp_dev_name(dev)) ||
 427             (dev->card && check_name(dev->card->name))))
 428                 return -ENODEV;
 429
 430         if (check_resources(dev))
 431                 return 0;
 432
 433         return -ENODEV;
 434 }
 435
 436 static int
 437 serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 438 {
 439         struct uart_8250_port uart, *port;
 440         int ret, line, flags = dev_id->driver_data;
 441
 442         if (flags & UNKNOWN_DEV) {
 443                 ret = serial_pnp_guess_board(dev);
 444                 if (ret < 0)
 445                         return ret;
 446         }
 447
 448         memset(&uart, 0, sizeof(uart));
 449         if (pnp_irq_valid(dev, 0))
 450                 uart.port.irq = pnp_irq(dev, 0);
 451         if ((flags & CIR_PORT) && pnp_port_valid(dev, 2)) {
 452                 uart.port.iobase = pnp_port_start(dev, 2);
 453                 uart.port.iotype = UPIO_PORT;
 454         } else if (pnp_port_valid(dev, 0)) {
 455                 uart.port.iobase = pnp_port_start(dev, 0);
 456                 uart.port.iotype = UPIO_PORT;
 457         } else if (pnp_mem_valid(dev, 0)) {
 458                 uart.port.mapbase = pnp_mem_start(dev, 0);
 459                 uart.port.iotype = UPIO_MEM;
 460                 uart.port.flags = UPF_IOREMAP;
 461         } else
 462                 return -ENODEV;
 463
 464         dev_dbg(&dev->dev,
 465                  "Setup PNP port: port %#lx, mem %#llx, irq %u, type %u\n",
 466                  uart.port.iobase, (unsigned long long)uart.port.mapbase,
 467                  uart.port.irq, uart.port.iotype);
 468
 469         if (flags & CIR_PORT) {
 470                 uart.port.flags |= UPF_FIXED_PORT | UPF_FIXED_TYPE;
 471                 uart.port.type = PORT_8250_CIR;
 472         }
 473
 474         uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
 475         if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
 476                 uart.port.flags |= UPF_SHARE_IRQ;
 477         uart.port.uartclk = 1843200;
 478         uart.port.dev = &dev->dev;
 479
 480         line = serial8250_register_8250_port(&uart);
 481         if (line < 0 || (flags & CIR_PORT))
 482                 return -ENODEV;
 483
 484         port = serial8250_get_port(line);
 485         if (uart_console(&port->port))
 486                 dev->capabilities |= PNP_CONSOLE;
 487
 488         pnp_set_drvdata(dev, (void *)((long)line + 1));
 489         return 0;
 490 }
 491
 492 static void serial_pnp_remove(struct pnp_dev *dev)
 493 {
 494         long line = (long)pnp_get_drvdata(dev);
 495
 496         dev->capabilities &= ~PNP_CONSOLE;
 497         if (line)
 498                 serial8250_unregister_port(line - 1);
 499 }
 500
 501 static int __maybe_unused serial_pnp_suspend(struct device *dev)
 502 {
 503         long line = (long)dev_get_drvdata(dev);
 504
 505         if (!line)
 506                 return -ENODEV;
 507         serial8250_suspend_port(line - 1);
 508         return 0;
 509 }
 510
 511 static int __maybe_unused serial_pnp_resume(struct device *dev)
 512 {
 513         long line = (long)dev_get_drvdata(dev);
 514
 515         if (!line)
 516                 return -ENODEV;
 517         serial8250_resume_port(line - 1);
 518         return 0;
 519 }
 520
 521 static SIMPLE_DEV_PM_OPS(serial_pnp_pm_ops, serial_pnp_suspend, serial_pnp_resume);
 522
 523 static struct pnp_driver serial_pnp_driver = {
 524         .name           = "serial",
 525         .probe          = serial_pnp_probe,
 526         .remove         = serial_pnp_remove,
 527         .driver         = {
 528                 .pm     = &serial_pnp_pm_ops,
 529         },
 530         .id_table       = pnp_dev_table,
 531 };
 532
 533 int serial8250_pnp_init(void)
 534 {
 535         return pnp_register_driver(&serial_pnp_driver);
 536 }
 537
 538 void serial8250_pnp_exit(void)
 539 {
 540         pnp_unregister_driver(&serial_pnp_driver);
 541 }
 542