ftdi.c - description
-------------------
begin : Fri Apr 4 2003
- copyright : (C) 2003-2008 by Intra2net AG
+ copyright : (C) 2003-2010 by Intra2net AG
email : opensource@intra2net.com
***************************************************************************/
{
int ret = 0;
- if (ftdi->usb_dev)
+ if (ftdi && ftdi->usb_dev)
{
ret = usb_close (ftdi->usb_dev);
ftdi->usb_dev = NULL;
\retval 0: all fine
\retval -1: unknown interface
+ \retval -2: USB device unavailable
*/
int ftdi_set_interface(struct ftdi_context *ftdi, enum ftdi_interface interface)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
switch (interface)
{
case INTERFACE_ANY:
*/
void ftdi_deinit(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL)
+ return;
+
ftdi_usb_close_internal (ftdi);
if (ftdi->async_usb_buffer != NULL)
*/
void ftdi_set_usbdev (struct ftdi_context *ftdi, usb_dev_handle *usb)
{
+ if (ftdi == NULL)
+ return;
+
ftdi->usb_dev = usb;
}
{
unsigned int packet_size;
+ // Sanity check
+ if (ftdi == NULL || dev == NULL)
+ return 64;
+
// Determine maximum packet size. Init with default value.
// New hi-speed devices from FTDI use a packet size of 512 bytes
// but could be connected to a normal speed USB hub -> 64 bytes packet size.
\retval -5: unable to claim device
\retval -6: reset failed
\retval -7: set baudrate failed
+ \retval -8: ftdi context invalid
*/
int ftdi_usb_open_dev(struct ftdi_context *ftdi, struct usb_device *dev)
{
int detach_errno = 0;
int config_val = 1;
+
+ if (ftdi == NULL)
+ ftdi_error_return(-8, "ftdi context invalid");
+
if (!(ftdi->usb_dev = usb_open(dev)))
ftdi_error_return(-4, "usb_open() failed");
\retval -8: get product description failed
\retval -9: get serial number failed
\retval -10: unable to close device
+ \retval -11: ftdi context invalid
*/
int ftdi_usb_open_desc_index(struct ftdi_context *ftdi, int vendor, int product,
const char* description, const char* serial, unsigned int index)
if (usb_find_devices() < 0)
ftdi_error_return(-2, "usb_find_devices() failed");
+ if (ftdi == NULL)
+ ftdi_error_return(-11, "ftdi context invalid");
+
for (bus = usb_get_busses(); bus; bus = bus->next)
{
for (dev = bus->devices; dev; dev = dev->next)
\retval -9: get serial number failed
\retval -10: unable to close device
\retval -11: illegal description format
+ \retval -12: ftdi context invalid
*/
int ftdi_usb_open_string(struct ftdi_context *ftdi, const char* description)
{
+ if (ftdi == NULL)
+ ftdi_error_return(-12, "ftdi context invalid");
+
if (description[0] == 0 || description[1] != ':')
ftdi_error_return(-11, "illegal description format");
\retval 0: all fine
\retval -1: FTDI reset failed
+ \retval -2: USB device unavailable
*/
int ftdi_usb_reset(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
SIO_RESET_REQUEST, SIO_RESET_SIO,
ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: read buffer purge failed
+ \retval -2: USB device unavailable
*/
int ftdi_usb_purge_rx_buffer(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
SIO_RESET_REQUEST, SIO_RESET_PURGE_RX,
ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: write buffer purge failed
+ \retval -2: USB device unavailable
*/
int ftdi_usb_purge_tx_buffer(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
SIO_RESET_REQUEST, SIO_RESET_PURGE_TX,
ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: read buffer purge failed
\retval -2: write buffer purge failed
+ \retval -3: USB device unavailable
*/
int ftdi_usb_purge_buffers(struct ftdi_context *ftdi)
{
int result;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-3, "USB device unavailable");
+
result = ftdi_usb_purge_rx_buffer(ftdi);
if (result < 0)
return -1;
\retval 0: all fine
\retval -1: usb_release failed
\retval -2: usb_close failed
+ \retval -3: ftdi context invalid
*/
int ftdi_usb_close(struct ftdi_context *ftdi)
{
int rtn = 0;
+ if (ftdi == NULL)
+ ftdi_error_return(-3, "ftdi context invalid");
+
#ifdef LIBFTDI_LINUX_ASYNC_MODE
/* try to release some kernel resources */
ftdi_async_complete(ftdi,1);
\retval 0: all fine
\retval -1: invalid baudrate
\retval -2: setting baudrate failed
+ \retval -3: USB device unavailable
*/
int ftdi_set_baudrate(struct ftdi_context *ftdi, int baudrate)
{
unsigned short value, index;
int actual_baudrate;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-3, "USB device unavailable");
+
if (ftdi->bitbang_enabled)
{
baudrate = baudrate*4;
\retval 0: all fine
\retval -1: Setting line property failed
+ \retval -2: USB device unavailable
*/
int ftdi_set_line_property2(struct ftdi_context *ftdi, enum ftdi_bits_type bits,
enum ftdi_stopbits_type sbit, enum ftdi_parity_type parity,
{
unsigned short value = bits;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
switch (parity)
{
case NONE:
\param buf Buffer with the data
\param size Size of the buffer
+ \retval -666: USB device unavailable
\retval <0: error code from usb_bulk_write()
\retval >0: number of bytes written
*/
int offset = 0;
int total_written = 0;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-666, "USB device unavailable");
+
while (offset < size)
{
int write_size = ftdi->writebuffer_chunksize;
\param buf Buffer with the data
\param size Size of the buffer
+ \retval -666: USB device unavailable
\retval <0: error code from usb_bulk_write()
\retval >0: number of bytes written
*/
int offset = 0;
int total_written = 0;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-666, "USB device unavailable");
+
while (offset < size)
{
int write_size = ftdi->writebuffer_chunksize;
\param chunksize Chunk size
\retval 0: all fine
+ \retval -1: ftdi context invalid
*/
int ftdi_write_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize)
{
+ if (ftdi == NULL)
+ ftdi_error_return(-1, "ftdi context invalid");
+
ftdi->writebuffer_chunksize = chunksize;
return 0;
}
\param chunksize Pointer to store chunk size in
\retval 0: all fine
+ \retval -1: ftdi context invalid
*/
int ftdi_write_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize)
{
+ if (ftdi == NULL)
+ ftdi_error_return(-1, "ftdi context invalid");
+
*chunksize = ftdi->writebuffer_chunksize;
return 0;
}
\param buf Buffer to store data in
\param size Size of the buffer
+ \retval -666: USB device unavailable
\retval <0: error code from usb_bulk_read()
\retval 0: no data was available
\retval >0: number of bytes read
int ftdi_read_data(struct ftdi_context *ftdi, unsigned char *buf, int size)
{
int offset = 0, ret = 1, i, num_of_chunks, chunk_remains;
- int packet_size = ftdi->max_packet_size;
+ int packet_size;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-666, "USB device unavailable");
+
+ packet_size = ftdi->max_packet_size;
// Packet size sanity check (avoid division by zero)
if (packet_size == 0)
ftdi_error_return(-1, "max_packet_size is bogus (zero)");
\param chunksize Chunk size
\retval 0: all fine
+ \retval -1: ftdi context invalid
*/
int ftdi_read_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize)
{
unsigned char *new_buf;
+ if (ftdi == NULL)
+ ftdi_error_return(-1, "ftdi context invalid");
+
// Invalidate all remaining data
ftdi->readbuffer_offset = 0;
ftdi->readbuffer_remaining = 0;
\param chunksize Pointer to store chunk size in
\retval 0: all fine
+ \retval -1: FTDI context invalid
*/
int ftdi_read_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize)
{
+ if (ftdi == NULL)
+ ftdi_error_return(-1, "FTDI context invalid");
+
*chunksize = ftdi->readbuffer_chunksize;
return 0;
}
\retval 0: all fine
\retval -1: can't enable bitbang mode
+ \retval -2: USB device unavailable
*/
int ftdi_enable_bitbang(struct ftdi_context *ftdi, unsigned char bitmask)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
usb_val = bitmask; // low byte: bitmask
/* FT2232C: Set bitbang_mode to 2 to enable SPI */
usb_val |= (ftdi->bitbang_mode << 8);
\retval 0: all fine
\retval -1: can't disable bitbang mode
+ \retval -2: USB device unavailable
*/
int ftdi_disable_bitbang(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_BITMODE_REQUEST, 0, ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
ftdi_error_return(-1, "unable to leave bitbang mode. Perhaps not a BM type chip?");
\retval 0: all fine
\retval -1: can't enable bitbang mode
+ \retval -2: USB device unavailable
*/
int ftdi_set_bitmode(struct ftdi_context *ftdi, unsigned char bitmask, unsigned char mode)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
usb_val = bitmask; // low byte: bitmask
usb_val |= (mode << 8);
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_BITMODE_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: read pins failed
+ \retval -2: USB device unavailable
*/
int ftdi_read_pins(struct ftdi_context *ftdi, unsigned char *pins)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_PINS_REQUEST, 0, ftdi->index, (char *)pins, 1, ftdi->usb_read_timeout) != 1)
ftdi_error_return(-1, "read pins failed");
\retval 0: all fine
\retval -1: latency out of range
\retval -2: unable to set latency timer
+ \retval -3: USB device unavailable
*/
int ftdi_set_latency_timer(struct ftdi_context *ftdi, unsigned char latency)
{
if (latency < 1)
ftdi_error_return(-1, "latency out of range. Only valid for 1-255");
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-3, "USB device unavailable");
+
usb_val = latency;
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_LATENCY_TIMER_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) != 0)
ftdi_error_return(-2, "unable to set latency timer");
\retval 0: all fine
\retval -1: unable to get latency timer
+ \retval -2: USB device unavailable
*/
int ftdi_get_latency_timer(struct ftdi_context *ftdi, unsigned char *latency)
{
unsigned short usb_val;
+
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_GET_LATENCY_TIMER_REQUEST, 0, ftdi->index, (char *)&usb_val, 1, ftdi->usb_read_timeout) != 1)
ftdi_error_return(-1, "reading latency timer failed");
\retval 0: all fine
\retval -1: unable to retrieve status information
+ \retval -2: USB device unavailable
*/
int ftdi_poll_modem_status(struct ftdi_context *ftdi, unsigned short *status)
{
char usb_val[2];
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_POLL_MODEM_STATUS_REQUEST, 0, ftdi->index, usb_val, 2, ftdi->usb_read_timeout) != 2)
ftdi_error_return(-1, "getting modem status failed");
\retval 0: all fine
\retval -1: set flow control failed
+ \retval -2: USB device unavailable
*/
int ftdi_setflowctrl(struct ftdi_context *ftdi, int flowctrl)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
SIO_SET_FLOW_CTRL_REQUEST, 0, (flowctrl | ftdi->index),
NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: set dtr failed
+ \retval -2: USB device unavailable
*/
int ftdi_setdtr(struct ftdi_context *ftdi, int state)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (state)
usb_val = SIO_SET_DTR_HIGH;
else
\param state state to set line to (1 or 0)
\retval 0: all fine
- \retval -1 set rts failed
+ \retval -1: set rts failed
+ \retval -2: USB device unavailable
*/
int ftdi_setrts(struct ftdi_context *ftdi, int state)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (state)
usb_val = SIO_SET_RTS_HIGH;
else
}
/**
- Set dtr and rts line in one pass
+ Set dtr and rts line in one pass
- \param ftdi pointer to ftdi_context
- \param dtr DTR state to set line to (1 or 0)
- \param rts RTS state to set line to (1 or 0)
+ \param ftdi pointer to ftdi_context
+ \param dtr DTR state to set line to (1 or 0)
+ \param rts RTS state to set line to (1 or 0)
- \retval 0: all fine
- \retval -1 set dtr/rts failed
+ \retval 0: all fine
+ \retval -1: set dtr/rts failed
+ \retval -2: USB device unavailable
*/
int ftdi_setdtr_rts(struct ftdi_context *ftdi, int dtr, int rts)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (dtr)
usb_val = SIO_SET_DTR_HIGH;
else
\retval 0: all fine
\retval -1: unable to set event character
+ \retval -2: USB device unavailable
*/
int ftdi_set_event_char(struct ftdi_context *ftdi,
unsigned char eventch, unsigned char enable)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
usb_val = eventch;
if (enable)
usb_val |= 1 << 8;
\retval 0: all fine
\retval -1: unable to set error character
+ \retval -2: USB device unavailable
*/
int ftdi_set_error_char(struct ftdi_context *ftdi,
unsigned char errorch, unsigned char enable)
{
unsigned short usb_val;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
usb_val = errorch;
if (enable)
usb_val |= 1 << 8;
*/
void ftdi_eeprom_setsize(struct ftdi_context *ftdi, struct ftdi_eeprom *eeprom, int size)
{
+ if (ftdi == NULL)
+ return;
+
ftdi->eeprom_size=size;
eeprom->size=size;
}
*/
void ftdi_eeprom_initdefaults(struct ftdi_eeprom *eeprom)
{
+ if (eeprom == NULL)
+ return;
+
eeprom->vendor_id = 0x0403;
eeprom->product_id = 0x6001;
}
/**
- Build binary output from ftdi_eeprom structure.
- Output is suitable for ftdi_write_eeprom().
+ Build binary output from ftdi_eeprom structure.
+ Output is suitable for ftdi_write_eeprom().
- \param eeprom Pointer to ftdi_eeprom
- \param output Buffer of 128 bytes to store eeprom image to
+ \param eeprom Pointer to ftdi_eeprom
+ \param output Buffer of 128 bytes to store eeprom image to
- \retval >0: used eeprom size
- \retval -1: eeprom size (128 bytes) exceeded by custom strings
+ \retval >0: used eeprom size
+ \retval -1: eeprom size (128 bytes) exceeded by custom strings
+ \retval -2: Invalid eeprom pointer
*/
int ftdi_eeprom_build(struct ftdi_eeprom *eeprom, unsigned char *output)
{
unsigned char manufacturer_size = 0, product_size = 0, serial_size = 0;
int size_check;
+ if (eeprom == NULL)
+ return -2;
+
if (eeprom->manufacturer != NULL)
manufacturer_size = strlen(eeprom->manufacturer);
if (eeprom->product != NULL)
unsigned char manufacturer_size = 0, product_size = 0, serial_size = 0;
int size_check;
int eeprom_size = 128;
+
+ if (eeprom == NULL)
+ return -1;
#if 0
size_check = eeprom->size;
size_check -= 28; // 28 are always in use (fixed)
\retval 0: all fine
\retval -1: read failed
+ \retval -2: USB device unavailable
*/
int ftdi_read_eeprom_location (struct ftdi_context *ftdi, int eeprom_addr, unsigned short *eeprom_val)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, eeprom_addr, (char *)eeprom_val, 2, ftdi->usb_read_timeout) != 2)
ftdi_error_return(-1, "reading eeprom failed");
\retval 0: all fine
\retval -1: read failed
+ \retval -2: USB device unavailable
*/
int ftdi_read_eeprom(struct ftdi_context *ftdi, unsigned char *eeprom)
{
int i;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
for (i = 0; i < ftdi->eeprom_size/2; i++)
{
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, i, eeprom+(i*2), 2, ftdi->usb_read_timeout) != 2)
\retval 0: all fine
\retval -1: read failed
+ \retval -2: USB device unavailable
*/
int ftdi_read_chipid(struct ftdi_context *ftdi, unsigned int *chipid)
{
unsigned int a = 0, b = 0;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, 0x43, (char *)&a, 2, ftdi->usb_read_timeout) == 2)
{
a = a << 8 | a >> 8;
}
/**
- Guesses size of eeprom by reading eeprom and comparing halves - will not work with blank eeprom
- Call this function then do a write then call again to see if size changes, if so write again.
+ Guesses size of eeprom by reading eeprom and comparing halves - will not work with blank eeprom
+ Call this function then do a write then call again to see if size changes, if so write again.
- \param ftdi pointer to ftdi_context
- \param eeprom Pointer to store eeprom into
- \param maxsize the size of the buffer to read into
+ \param ftdi pointer to ftdi_context
+ \param eeprom Pointer to store eeprom into
+ \param maxsize the size of the buffer to read into
- \retval size of eeprom
+ \retval -1: eeprom read failed
+ \retval -2: USB device unavailable
+ \retval >=0: size of eeprom
*/
int ftdi_read_eeprom_getsize(struct ftdi_context *ftdi, unsigned char *eeprom, int maxsize)
{
int i=0,j,minsize=32;
int size=minsize;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
do
{
for (j = 0; i < maxsize/2 && j<size; j++)
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE,
SIO_READ_EEPROM_REQUEST, 0, i,
eeprom+(i*2), 2, ftdi->usb_read_timeout) != 2)
- ftdi_error_return(-1, "reading eeprom failed");
+ ftdi_error_return(-1, "eeprom read failed");
i++;
}
size*=2;
\retval 0: all fine
\retval -1: read failed
+ \retval -2: USB device unavailable
*/
int ftdi_write_eeprom_location(struct ftdi_context *ftdi, int eeprom_addr, unsigned short eeprom_val)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
SIO_WRITE_EEPROM_REQUEST, eeprom_val, eeprom_addr,
NULL, 0, ftdi->usb_write_timeout) != 0)
\retval 0: all fine
\retval -1: read failed
+ \retval -2: USB device unavailable
*/
int ftdi_write_eeprom(struct ftdi_context *ftdi, unsigned char *eeprom)
{
unsigned short usb_val, status;
int i, ret;
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
/* These commands were traced while running MProg */
if ((ret = ftdi_usb_reset(ftdi)) != 0)
return ret;
\retval 0: all fine
\retval -1: erase failed
+ \retval -2: USB device unavailable
*/
int ftdi_erase_eeprom(struct ftdi_context *ftdi)
{
+ if (ftdi == NULL || ftdi->usb_dev == NULL)
+ ftdi_error_return(-2, "USB device unavailable");
+
if (usb_control_msg(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_ERASE_EEPROM_REQUEST, 0, 0, NULL, 0, ftdi->usb_write_timeout) != 0)
ftdi_error_return(-1, "unable to erase eeprom");
*/
char *ftdi_get_error_string (struct ftdi_context *ftdi)
{
+ if (ftdi == NULL)
+ return "";
+
return ftdi->error_str;
}
git://developer.intra2net.com / libftdi / commitdiff