Add support for the GOEPEL PicoTAP programmer

http://www.goepel.com/en/jtagboundary-scan/hardware/picotap.html

This device is actually a JTAG adapter, but since it uses standard
FT2232 A interface pins, it can be easily used as SPI programmer
(tested it here successfully). PicoTAP supports only 5V output, so one
needs to reduce this to 3.3V in a same manner as DLP Design DLP-USB1232H, see

  http://flashrom.org/FT2232SPI_Programmer#DLP_Design_DLP-USB1232H

for details.

The PicoTAP pin-out is as follows:

  PicoTAP |  SPI
 ---------+-------
    TCK   | SCLK
    TMS   |  CS#
    TDI   |  SO
    TDO   |  SI
   /TRST  |  -
    GND   |  GND
    +5V   |  VCC, HOLD# & WP# after 3.3V regulator

I managed to run PicoTAP in 10MHz, 15MHz and 30MHz modes (by forcing
DIVIDE_BY), against SST25VF016B SPI flash, read/write/erase all worked
fine (write seems somewhat slow).

Corresponding to flashrom svn r1453.

Signed-off-by: Samir Ibradžić <sibradzic@gmail.com>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
3 files changed