drivers/usb/serial/ftdi_sio.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Driver definitions for the FTDI USB Single Port Serial Converter -
   4  * known as FTDI_SIO (Serial Input/Output application of the chipset)
   5  *
   6  * For USB vendor/product IDs (VID/PID), please see ftdi_sio_ids.h
   7  *
   8  *
   9  * The example I have is known as the USC-1000 which is available from
  10  * http://www.dse.co.nz - cat no XH4214 It looks similar to this:
  11  * http://www.dansdata.com/usbser.htm but I can't be sure There are other
  12  * USC-1000s which don't look like my device though so beware!
  13  *
  14  * The device is based on the FTDI FT8U100AX chip. It has a DB25 on one side,
  15  * USB on the other.
  16  *
  17  * Thanx to FTDI (http://www.ftdichip.com) for so kindly providing details
  18  * of the protocol required to talk to the device and ongoing assistence
  19  * during development.
  20  *
  21  * Bill Ryder - bryder@sgi.com formerly of Silicon Graphics, Inc.- wrote the
  22  * FTDI_SIO implementation.
  23  *
  24  */
  25
  26 /* Commands */
  27 #define FTDI_SIO_RESET                  0 /* Reset the port */
  28 #define FTDI_SIO_MODEM_CTRL             1 /* Set the modem control register */
  29 #define FTDI_SIO_SET_FLOW_CTRL          2 /* Set flow control register */
  30 #define FTDI_SIO_SET_BAUD_RATE          3 /* Set baud rate */
  31 #define FTDI_SIO_SET_DATA               4 /* Set the data characteristics of
  32                                              the port */
  33 #define FTDI_SIO_GET_MODEM_STATUS       5 /* Retrieve current value of modem
  34                                              status register */
  35 #define FTDI_SIO_SET_EVENT_CHAR         6 /* Set the event character */
  36 #define FTDI_SIO_SET_ERROR_CHAR         7 /* Set the error character */
  37 #define FTDI_SIO_SET_LATENCY_TIMER      9 /* Set the latency timer */
  38 #define FTDI_SIO_GET_LATENCY_TIMER      10 /* Get the latency timer */
  39
  40 /* Interface indices for FT2232, FT2232H and FT4232H devices */
  41 #define INTERFACE_A             1
  42 #define INTERFACE_B             2
  43 #define INTERFACE_C             3
  44 #define INTERFACE_D             4
  45
  46
  47 /*
  48  *   BmRequestType:  1100 0000b
  49  *   bRequest:       FTDI_E2_READ
  50  *   wValue:         0
  51  *   wIndex:         Address of word to read
  52  *   wLength:        2
  53  *   Data:           Will return a word of data from E2Address
  54  *
  55  */
  56
  57 /* Port Identifier Table */
  58 #define PIT_DEFAULT             0 /* SIOA */
  59 #define PIT_SIOA                1 /* SIOA */
  60 /* The device this driver is tested with one has only one port */
  61 #define PIT_SIOB                2 /* SIOB */
  62 #define PIT_PARALLEL            3 /* Parallel */
  63
  64 /* FTDI_SIO_RESET */
  65 #define FTDI_SIO_RESET_REQUEST FTDI_SIO_RESET
  66 #define FTDI_SIO_RESET_REQUEST_TYPE 0x40
  67 #define FTDI_SIO_RESET_SIO 0
  68 #define FTDI_SIO_RESET_PURGE_RX 1
  69 #define FTDI_SIO_RESET_PURGE_TX 2
  70
  71 /*
  72  * BmRequestType:  0100 0000B
  73  * bRequest:       FTDI_SIO_RESET
  74  * wValue:         Control Value
  75  *                   0 = Reset SIO
  76  *                   1 = Purge RX buffer
  77  *                   2 = Purge TX buffer
  78  * wIndex:         Port
  79  * wLength:        0
  80  * Data:           None
  81  *
  82  * The Reset SIO command has this effect:
  83  *
  84  *    Sets flow control set to 'none'
  85  *    Event char = $0D
  86  *    Event trigger = disabled
  87  *    Purge RX buffer
  88  *    Purge TX buffer
  89  *    Clear DTR
  90  *    Clear RTS
  91  *    baud and data format not reset
  92  *
  93  * The Purge RX and TX buffer commands affect nothing except the buffers
  94  *
  95    */
  96
  97 /* FTDI_SIO_SET_BAUDRATE */
  98 #define FTDI_SIO_SET_BAUDRATE_REQUEST_TYPE 0x40
  99 #define FTDI_SIO_SET_BAUDRATE_REQUEST 3
 100
 101 /*
 102  * BmRequestType:  0100 0000B
 103  * bRequest:       FTDI_SIO_SET_BAUDRATE
 104  * wValue:         BaudDivisor value - see below
 105  * wIndex:         Port
 106  * wLength:        0
 107  * Data:           None
 108  * The BaudDivisor values are calculated as follows:
 109  * - BaseClock is either 12000000 or 48000000 depending on the device.
 110  *   FIXME: I wish I knew how to detect old chips to select proper base clock!
 111  * - BaudDivisor is a fixed point number encoded in a funny way.
 112  *   (--WRONG WAY OF THINKING--)
 113  *   BaudDivisor is a fixed point number encoded with following bit weighs:
 114  *   (-2)(-1)(13..0). It is a radical with a denominator of 4, so values
 115  *   end with 0.0 (00...), 0.25 (10...), 0.5 (01...), and 0.75 (11...).
 116  *   (--THE REALITY--)
 117  *   The both-bits-set has quite different meaning from 0.75 - the chip
 118  *   designers have decided it to mean 0.125 instead of 0.75.
 119  *   This info looked up in FTDI application note "FT8U232 DEVICES \ Data Rates
 120  *   and Flow Control Consideration for USB to RS232".
 121  * - BaudDivisor = (BaseClock / 16) / BaudRate, where the (=) operation should
 122  *   automagically re-encode the resulting value to take fractions into
 123  *   consideration.
 124  * As all values are integers, some bit twiddling is in order:
 125  *   BaudDivisor = (BaseClock / 16 / BaudRate) |
 126  *   (((BaseClock / 2 / BaudRate) & 4) ? 0x4000    // 0.5
 127  *    : ((BaseClock / 2 / BaudRate) & 2) ? 0x8000  // 0.25
 128  *    : ((BaseClock / 2 / BaudRate) & 1) ? 0xc000  // 0.125
 129  *    : 0)
 130  *
 131  * For the FT232BM, a 17th divisor bit was introduced to encode the multiples
 132  * of 0.125 missing from the FT8U232AM.  Bits 16 to 14 are coded as follows
 133  * (the first four codes are the same as for the FT8U232AM, where bit 16 is
 134  * always 0):
 135  *   000 - add .000 to divisor
 136  *   001 - add .500 to divisor
 137  *   010 - add .250 to divisor
 138  *   011 - add .125 to divisor
 139  *   100 - add .375 to divisor
 140  *   101 - add .625 to divisor
 141  *   110 - add .750 to divisor
 142  *   111 - add .875 to divisor
 143  * Bits 15 to 0 of the 17-bit divisor are placed in the urb value.  Bit 16 is
 144  * placed in bit 0 of the urb index.
 145  *
 146  * Note that there are a couple of special cases to support the highest baud
 147  * rates.  If the calculated divisor value is 1, this needs to be replaced with
 148  * 0.  Additionally for the FT232BM, if the calculated divisor value is 0x4001
 149  * (1.5), this needs to be replaced with 0x0001 (1) (but this divisor value is
 150  * not supported by the FT8U232AM).
 151  */
 152
 153 enum ftdi_chip_type {
 154         SIO = 1,
 155         FT8U232AM = 2,
 156         FT232BM = 3,
 157         FT2232C = 4,
 158         FT232RL = 5,
 159         FT2232H = 6,
 160         FT4232H = 7,
 161         FT232H  = 8,
 162         FTX     = 9,
 163 };
 164
 165 enum ftdi_sio_baudrate {
 166         ftdi_sio_b300 = 0,
 167         ftdi_sio_b600 = 1,
 168         ftdi_sio_b1200 = 2,
 169         ftdi_sio_b2400 = 3,
 170         ftdi_sio_b4800 = 4,
 171         ftdi_sio_b9600 = 5,
 172         ftdi_sio_b19200 = 6,
 173         ftdi_sio_b38400 = 7,
 174         ftdi_sio_b57600 = 8,
 175         ftdi_sio_b115200 = 9
 176 };
 177
 178 /*
 179  * The ftdi_8U232AM_xxMHz_byyy constants have been removed. The encoded divisor
 180  * values are calculated internally.
 181  */
 182 #define FTDI_SIO_SET_DATA_REQUEST       FTDI_SIO_SET_DATA
 183 #define FTDI_SIO_SET_DATA_REQUEST_TYPE  0x40
 184 #define FTDI_SIO_SET_DATA_PARITY_NONE   (0x0 << 8)
 185 #define FTDI_SIO_SET_DATA_PARITY_ODD    (0x1 << 8)
 186 #define FTDI_SIO_SET_DATA_PARITY_EVEN   (0x2 << 8)
 187 #define FTDI_SIO_SET_DATA_PARITY_MARK   (0x3 << 8)
 188 #define FTDI_SIO_SET_DATA_PARITY_SPACE  (0x4 << 8)
 189 #define FTDI_SIO_SET_DATA_STOP_BITS_1   (0x0 << 11)
 190 #define FTDI_SIO_SET_DATA_STOP_BITS_15  (0x1 << 11)
 191 #define FTDI_SIO_SET_DATA_STOP_BITS_2   (0x2 << 11)
 192 #define FTDI_SIO_SET_BREAK              (0x1 << 14)
 193 /* FTDI_SIO_SET_DATA */
 194
 195 /*
 196  * BmRequestType:  0100 0000B
 197  * bRequest:       FTDI_SIO_SET_DATA
 198  * wValue:         Data characteristics (see below)
 199  * wIndex:         Port
 200  * wLength:        0
 201  * Data:           No
 202  *
 203  * Data characteristics
 204  *
 205  *   B0..7   Number of data bits
 206  *   B8..10  Parity
 207  *           0 = None
 208  *           1 = Odd
 209  *           2 = Even
 210  *           3 = Mark
 211  *           4 = Space
 212  *   B11..13 Stop Bits
 213  *           0 = 1
 214  *           1 = 1.5
 215  *           2 = 2
 216  *   B14
 217  *           1 = TX ON (break)
 218  *           0 = TX OFF (normal state)
 219  *   B15 Reserved
 220  *
 221  */
 222
 223
 224
 225 /* FTDI_SIO_MODEM_CTRL */
 226 #define FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE 0x40
 227 #define FTDI_SIO_SET_MODEM_CTRL_REQUEST FTDI_SIO_MODEM_CTRL
 228
 229 /*
 230  * BmRequestType:   0100 0000B
 231  * bRequest:        FTDI_SIO_MODEM_CTRL
 232  * wValue:          ControlValue (see below)
 233  * wIndex:          Port
 234  * wLength:         0
 235  * Data:            None
 236  *
 237  * NOTE: If the device is in RTS/CTS flow control, the RTS set by this
 238  * command will be IGNORED without an error being returned
 239  * Also - you can not set DTR and RTS with one control message
 240  */
 241
 242 #define FTDI_SIO_SET_DTR_MASK 0x1
 243 #define FTDI_SIO_SET_DTR_HIGH ((FTDI_SIO_SET_DTR_MASK  << 8) | 1)
 244 #define FTDI_SIO_SET_DTR_LOW  ((FTDI_SIO_SET_DTR_MASK  << 8) | 0)
 245 #define FTDI_SIO_SET_RTS_MASK 0x2
 246 #define FTDI_SIO_SET_RTS_HIGH ((FTDI_SIO_SET_RTS_MASK << 8) | 2)
 247 #define FTDI_SIO_SET_RTS_LOW  ((FTDI_SIO_SET_RTS_MASK << 8) | 0)
 248
 249 /*
 250  * ControlValue
 251  * B0    DTR state
 252  *          0 = reset
 253  *          1 = set
 254  * B1    RTS state
 255  *          0 = reset
 256  *          1 = set
 257  * B2..7 Reserved
 258  * B8    DTR state enable
 259  *          0 = ignore
 260  *          1 = use DTR state
 261  * B9    RTS state enable
 262  *          0 = ignore
 263  *          1 = use RTS state
 264  * B10..15 Reserved
 265  */
 266
 267 /* FTDI_SIO_SET_FLOW_CTRL */
 268 #define FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE 0x40
 269 #define FTDI_SIO_SET_FLOW_CTRL_REQUEST FTDI_SIO_SET_FLOW_CTRL
 270 #define FTDI_SIO_DISABLE_FLOW_CTRL 0x0
 271 #define FTDI_SIO_RTS_CTS_HS (0x1 << 8)
 272 #define FTDI_SIO_DTR_DSR_HS (0x2 << 8)
 273 #define FTDI_SIO_XON_XOFF_HS (0x4 << 8)
 274 /*
 275  *   BmRequestType:  0100 0000b
 276  *   bRequest:       FTDI_SIO_SET_FLOW_CTRL
 277  *   wValue:         Xoff/Xon
 278  *   wIndex:         Protocol/Port - hIndex is protocol / lIndex is port
 279  *   wLength:        0
 280  *   Data:           None
 281  *
 282  * hIndex protocol is:
 283  *   B0 Output handshaking using RTS/CTS
 284  *       0 = disabled
 285  *       1 = enabled
 286  *   B1 Output handshaking using DTR/DSR
 287  *       0 = disabled
 288  *       1 = enabled
 289  *   B2 Xon/Xoff handshaking
 290  *       0 = disabled
 291  *       1 = enabled
 292  *
 293  * A value of zero in the hIndex field disables handshaking
 294  *
 295  * If Xon/Xoff handshaking is specified, the hValue field should contain the
 296  * XOFF character and the lValue field contains the XON character.
 297  */
 298
 299 /*
 300  * FTDI_SIO_GET_LATENCY_TIMER
 301  *
 302  * Set the timeout interval. The FTDI collects data from the slave
 303  * device, transmitting it to the host when either A) 62 bytes are
 304  * received, or B) the timeout interval has elapsed and the buffer
 305  * contains at least 1 byte.  Setting this value to a small number
 306  * can dramatically improve performance for applications which send
 307  * small packets, since the default value is 16ms.
 308  */
 309 #define  FTDI_SIO_GET_LATENCY_TIMER_REQUEST FTDI_SIO_GET_LATENCY_TIMER
 310 #define  FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE 0xC0
 311
 312 /*
 313  *  BmRequestType:   1100 0000b
 314  *  bRequest:        FTDI_SIO_GET_LATENCY_TIMER
 315  *  wValue:          0
 316  *  wIndex:          Port
 317  *  wLength:         0
 318  *  Data:            latency (on return)
 319  */
 320
 321 /*
 322  * FTDI_SIO_SET_LATENCY_TIMER
 323  *
 324  * Set the timeout interval. The FTDI collects data from the slave
 325  * device, transmitting it to the host when either A) 62 bytes are
 326  * received, or B) the timeout interval has elapsed and the buffer
 327  * contains at least 1 byte.  Setting this value to a small number
 328  * can dramatically improve performance for applications which send
 329  * small packets, since the default value is 16ms.
 330  */
 331 #define  FTDI_SIO_SET_LATENCY_TIMER_REQUEST FTDI_SIO_SET_LATENCY_TIMER
 332 #define  FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE 0x40
 333
 334 /*
 335  *  BmRequestType:   0100 0000b
 336  *  bRequest:        FTDI_SIO_SET_LATENCY_TIMER
 337  *  wValue:          Latency (milliseconds)
 338  *  wIndex:          Port
 339  *  wLength:         0
 340  *  Data:            None
 341  *
 342  * wValue:
 343  *   B0..7   Latency timer
 344  *   B8..15  0
 345  *
 346  */
 347
 348 /*
 349  * FTDI_SIO_SET_EVENT_CHAR
 350  *
 351  * Set the special event character for the specified communications port.
 352  * If the device sees this character it will immediately return the
 353  * data read so far - rather than wait 40ms or until 62 bytes are read
 354  * which is what normally happens.
 355  */
 356
 357
 358 #define  FTDI_SIO_SET_EVENT_CHAR_REQUEST FTDI_SIO_SET_EVENT_CHAR
 359 #define  FTDI_SIO_SET_EVENT_CHAR_REQUEST_TYPE 0x40
 360
 361
 362 /*
 363  *  BmRequestType:   0100 0000b
 364  *  bRequest:        FTDI_SIO_SET_EVENT_CHAR
 365  *  wValue:          EventChar
 366  *  wIndex:          Port
 367  *  wLength:         0
 368  *  Data:            None
 369  *
 370  * wValue:
 371  *   B0..7   Event Character
 372  *   B8      Event Character Processing
 373  *             0 = disabled
 374  *             1 = enabled
 375  *   B9..15  Reserved
 376  *
 377  */
 378
 379 /* FTDI_SIO_SET_ERROR_CHAR */
 380
 381 /*
 382  * Set the parity error replacement character for the specified communications
 383  * port
 384  */
 385
 386 /*
 387  *  BmRequestType:  0100 0000b
 388  *  bRequest:       FTDI_SIO_SET_EVENT_CHAR
 389  *  wValue:         Error Char
 390  *  wIndex:         Port
 391  *  wLength:        0
 392  *  Data:           None
 393  *
 394  *Error Char
 395  *  B0..7  Error Character
 396  *  B8     Error Character Processing
 397  *           0 = disabled
 398  *           1 = enabled
 399  *  B9..15 Reserved
 400  *
 401  */
 402
 403 /* FTDI_SIO_GET_MODEM_STATUS */
 404 /* Retrieve the current value of the modem status register */
 405
 406 #define FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE 0xc0
 407 #define FTDI_SIO_GET_MODEM_STATUS_REQUEST FTDI_SIO_GET_MODEM_STATUS
 408 #define FTDI_SIO_CTS_MASK 0x10
 409 #define FTDI_SIO_DSR_MASK 0x20
 410 #define FTDI_SIO_RI_MASK  0x40
 411 #define FTDI_SIO_RLSD_MASK 0x80
 412 /*
 413  *   BmRequestType:   1100 0000b
 414  *   bRequest:        FTDI_SIO_GET_MODEM_STATUS
 415  *   wValue:          zero
 416  *   wIndex:          Port
 417  *   wLength:         1
 418  *   Data:            Status
 419  *
 420  * One byte of data is returned
 421  * B0..3 0
 422  * B4    CTS
 423  *         0 = inactive
 424  *         1 = active
 425  * B5    DSR
 426  *         0 = inactive
 427  *         1 = active
 428  * B6    Ring Indicator (RI)
 429  *         0 = inactive
 430  *         1 = active
 431  * B7    Receive Line Signal Detect (RLSD)
 432  *         0 = inactive
 433  *         1 = active
 434  */
 435
 436
 437
 438 /* Descriptors returned by the device
 439  *
 440  *  Device Descriptor
 441  *
 442  * Offset       Field           Size    Value   Description
 443  * 0    bLength         1       0x12    Size of descriptor in bytes
 444  * 1    bDescriptorType 1       0x01    DEVICE Descriptor Type
 445  * 2    bcdUSB          2       0x0110  USB Spec Release Number
 446  * 4    bDeviceClass    1       0x00    Class Code
 447  * 5    bDeviceSubClass 1       0x00    SubClass Code
 448  * 6    bDeviceProtocol 1       0x00    Protocol Code
 449  * 7    bMaxPacketSize0 1       0x08    Maximum packet size for endpoint 0
 450  * 8    idVendor        2       0x0403  Vendor ID
 451  * 10   idProduct       2       0x8372  Product ID (FTDI_SIO_PID)
 452  * 12   bcdDevice       2       0x0001  Device release number
 453  * 14   iManufacturer   1       0x01    Index of man. string desc
 454  * 15   iProduct        1       0x02    Index of prod string desc
 455  * 16   iSerialNumber   1       0x02    Index of serial nmr string desc
 456  * 17   bNumConfigurations 1    0x01    Number of possible configurations
 457  *
 458  * Configuration Descriptor
 459  *
 460  * Offset       Field                   Size    Value
 461  * 0    bLength                 1       0x09    Size of descriptor in bytes
 462  * 1    bDescriptorType         1       0x02    CONFIGURATION Descriptor Type
 463  * 2    wTotalLength            2       0x0020  Total length of data
 464  * 4    bNumInterfaces          1       0x01    Number of interfaces supported
 465  * 5    bConfigurationValue     1       0x01    Argument for SetCOnfiguration() req
 466  * 6    iConfiguration          1       0x02    Index of config string descriptor
 467  * 7    bmAttributes            1       0x20    Config characteristics Remote Wakeup
 468  * 8    MaxPower                1       0x1E    Max power consumption
 469  *
 470  * Interface Descriptor
 471  *
 472  * Offset       Field                   Size    Value
 473  * 0    bLength                 1       0x09    Size of descriptor in bytes
 474  * 1    bDescriptorType         1       0x04    INTERFACE Descriptor Type
 475  * 2    bInterfaceNumber        1       0x00    Number of interface
 476  * 3    bAlternateSetting       1       0x00    Value used to select alternate
 477  * 4    bNumEndpoints           1       0x02    Number of endpoints
 478  * 5    bInterfaceClass         1       0xFF    Class Code
 479  * 6    bInterfaceSubClass      1       0xFF    Subclass Code
 480  * 7    bInterfaceProtocol      1       0xFF    Protocol Code
 481  * 8    iInterface              1       0x02    Index of interface string description
 482  *
 483  * IN Endpoint Descriptor
 484  *
 485  * Offset       Field                   Size    Value
 486  * 0    bLength                 1       0x07    Size of descriptor in bytes
 487  * 1    bDescriptorType         1       0x05    ENDPOINT descriptor type
 488  * 2    bEndpointAddress        1       0x82    Address of endpoint
 489  * 3    bmAttributes            1       0x02    Endpoint attributes - Bulk
 490  * 4    bNumEndpoints           2       0x0040  maximum packet size
 491  * 5    bInterval               1       0x00    Interval for polling endpoint
 492  *
 493  * OUT Endpoint Descriptor
 494  *
 495  * Offset       Field                   Size    Value
 496  * 0    bLength                 1       0x07    Size of descriptor in bytes
 497  * 1    bDescriptorType         1       0x05    ENDPOINT descriptor type
 498  * 2    bEndpointAddress        1       0x02    Address of endpoint
 499  * 3    bmAttributes            1       0x02    Endpoint attributes - Bulk
 500  * 4    bNumEndpoints           2       0x0040  maximum packet size
 501  * 5    bInterval               1       0x00    Interval for polling endpoint
 502  *
 503  * DATA FORMAT
 504  *
 505  * IN Endpoint
 506  *
 507  * The device reserves the first two bytes of data on this endpoint to contain
 508  * the current values of the modem and line status registers. In the absence of
 509  * data, the device generates a message consisting of these two status bytes
 510  * every 40 ms
 511  *
 512  * Byte 0: Modem Status
 513  *
 514  * Offset       Description
 515  * B0   Reserved - must be 1
 516  * B1   Reserved - must be 0
 517  * B2   Reserved - must be 0
 518  * B3   Reserved - must be 0
 519  * B4   Clear to Send (CTS)
 520  * B5   Data Set Ready (DSR)
 521  * B6   Ring Indicator (RI)
 522  * B7   Receive Line Signal Detect (RLSD)
 523  *
 524  * Byte 1: Line Status
 525  *
 526  * Offset       Description
 527  * B0   Data Ready (DR)
 528  * B1   Overrun Error (OE)
 529  * B2   Parity Error (PE)
 530  * B3   Framing Error (FE)
 531  * B4   Break Interrupt (BI)
 532  * B5   Transmitter Holding Register (THRE)
 533  * B6   Transmitter Empty (TEMT)
 534  * B7   Error in RCVR FIFO
 535  *
 536  */
 537 #define FTDI_RS0_CTS    (1 << 4)
 538 #define FTDI_RS0_DSR    (1 << 5)
 539 #define FTDI_RS0_RI     (1 << 6)
 540 #define FTDI_RS0_RLSD   (1 << 7)
 541
 542 #define FTDI_RS_DR      1
 543 #define FTDI_RS_OE      (1<<1)
 544 #define FTDI_RS_PE      (1<<2)
 545 #define FTDI_RS_FE      (1<<3)
 546 #define FTDI_RS_BI      (1<<4)
 547 #define FTDI_RS_THRE    (1<<5)
 548 #define FTDI_RS_TEMT    (1<<6)
 549 #define FTDI_RS_FIFO    (1<<7)
 550
 551 /*
 552  * OUT Endpoint
 553  *
 554  * This device reserves the first bytes of data on this endpoint contain the
 555  * length and port identifier of the message. For the FTDI USB Serial converter
 556  * the port identifier is always 1.
 557  *
 558  * Byte 0: Line Status
 559  *
 560  * Offset       Description
 561  * B0   Reserved - must be 1
 562  * B1   Reserved - must be 0
 563  * B2..7        Length of message - (not including Byte 0)
 564  *
 565  */