Jonas Horberg [jhorberg@sauer-danfoss.com]

https://lists.berlios.de/pipermail/openocd-development/2009-August/009939.html

1. It can only be built with the FTD2XX driver. libftdi supports FT2232H/FT4232H 
since version 0.16 

2. A speed value of 0 is used as a RTCK request indicator. This clashes with the 
valid clock division value 0 that provide the highest fixed clock frequency. 

3. The ft2232_speed_div function return the maximum selectable frequency (30MHz) 
when RTCK is activated. It should return 0. 

4. The ft2232_khz function return ERROR_OK when RTCK is requested even for 
devices lacking RTCK support. It should return ERROR_FAIL so the upper driver layers 
can detect this and try to fallback to a fixed frequency. 

5. FT2232H/FT4232H have a backward compatibility function that divide the clock 
by 5 to get the same frequency range as FT2232D. There is no code that disable 
this functionality. I can not find anything about if this is enabled or disabled by default. 
I think it is safest to actively disable it. 


git-svn-id: svn://svn.berlios.de/openocd/trunk@2591 b42882b7-edfa-0310-969c-e2dbd0fdcd60

3 files changed, 229 insertions, 217 deletions

diff --git a/README b/README
index e3b49a93..d95d689c 100644
--- a/README
+++ b/README
@@ -125,7 +125,7 @@ Building OpenOCD
 The INSTALL file contains generic instructions for running 'configure'
 and compiling the OpenOCD source code.  That file is provided by default
 for all GNU automake packages.  If you are not familiar with the GNU
-autotools, then you should read those instructions first.  
+autotools, then you should read those instructions first.
 
 The remainder of this document tries to provide some instructions for
 those looking for a quick-install.
@@ -163,7 +163,7 @@ To build OpenOCD (on both Linux and Cygwin), use the following sequence
 of commands:
 
    ./configure [with some options listed in the next section]
-   make 
+   make
    make install
 
 The 'configure' step generates the Makefiles required to build OpenOCD,
@@ -180,7 +180,7 @@ the 'configure' script.  For example, you can configure OpenOCD to
 cross-compile on a x86 Linux host to run on Windows (MinGW32), you could
 use the following configuration options:
 
-  ./configure --build=i686-pc-linux-gnu --host=i586-mingw32msvc ... 
+  ./configure --build=i686-pc-linux-gnu --host=i586-mingw32msvc ...
 
 Likewise, the following options allow OpenOCD to be cross-compiled for
 an ARM target on the same x86 host:
@@ -215,9 +215,10 @@ options may be available there:
                           FTD2XX
   --enable-ft2232_ftd2xx  Enable building support for FT2232 based devices
                           using the FTD2XX driver from ftdichip.com
-  --enable-ftd2xx-highspeed
+  --enable-ft2232-highspeed
                           Enable building support for FT2232H and
-                          FT4232H-based devices (requires >=libftd2xx-0.4.16)
+                          FT4232H-based devices (requires >=libftd2xx-0.4.16
+                          or >=libftdi-0.16)
 
   --enable-gw16012        Enable building support for the Gateworks GW16012
                           JTAG Programmer
@@ -301,12 +302,12 @@ have to use both the --enable-parport AND the --enable-parport-giveio
 option if you want to use giveio instead of ioperm parallel port access
 method.
 
-FT2232C Based USB Dongles 
+FT2232C Based USB Dongles
 -------------------------
 
 There are 2 methods of using the FTD2232, either (1) using the
 FTDICHIP.COM closed source driver, or (2) the open (and free) driver
-libftdi. 
+libftdi.
 
 Using LIBFTDI
 -------------
@@ -320,7 +321,7 @@ installed.  To use the newer FT2232H chips, supporting RTCK and USB high
 speed (480 Mbps), you need libftdi version 0.16 or newer.  Many Linux
 distributions provide suitable packages for these libraries.
 
-For Windows, libftdi is supported with versions 0.14 and later.  
+For Windows, libftdi is supported with versions 0.14 and later.
 
 With these prerequisites met, configure the libftdi solution like this:
 
@@ -340,7 +341,7 @@ copies for personal use.
 The FTDICHIP drivers come as either a (win32) ZIP file, or a (Linux)
 TAR.GZ file. You must unpack them ``some where'' convient. As of this
 writing FTDICHIP does not supply means to install these files "in an
-appropriate place."  
+appropriate place."
 
 If your distribution does not package these, there are several
 './configure' options to solve this problem:
@@ -361,7 +362,7 @@ Windows or Linux FTD2xx drivers from the following location:
 Remember, this library is binary-only, while OpenOCD is licenced
 according to GNU GPLv2 without any exceptions.  That means that
 _distributing_ copies of OpenOCD built with the FTDI code would violate
-the OpenOCD licensing terms.  
+the OpenOCD licensing terms.
 
 Linux Notes
 ***********
@@ -404,7 +405,7 @@ Tips For Building From The Subversion Repository
 ************************************************
 
 Building OpenOCD from a repository requires a recent version of the GNU
-autotools (autoconf >= 2.59 and automake >= 1.9).  
+autotools (autoconf >= 2.59 and automake >= 1.9).
 
 1) Run './bootstrap' to create the 'configure' script and prepare
    the build process for your host system.
diff --git a/configure.in b/configure.in
index 79a650cc..0b2bcf67 100644
--- a/configure.in
+++ b/configure.in
@@ -128,7 +128,7 @@ then
     # Nonstandard --prefix and/or --exec-prefix
     # We have an override of some sort.
     # use build specific install library dir
-    
+
     LDFLAGS="$LDFLAGS -L$OCDxprefix/lib"
     # RPATH becomes an issue on Linux only
     if test $host_os = linux-gnu || test $host_os = linux ; then
@@ -146,7 +146,7 @@ cat << __EOF__
 
 The option: --with-ftd2xx=<PATH> has been removed.
 On Linux, the new option is:
-  
+
   --with-ftd2xx-linux-tardir=/path/to/files
 
 Where <path> is the path the the directory where the "tar.gz" file
@@ -245,7 +245,7 @@ debug_usb_comms=no
 
 AC_ARG_ENABLE(verbose,
   AS_HELP_STRING([--enable-verbose],
-      [Enable verbose JTAG I/O messages (for debugging).]), 
+      [Enable verbose JTAG I/O messages (for debugging).]),
   [
   debug_jtag_io=$enableval
   debug_usb_io=$enableval
@@ -254,15 +254,15 @@ AC_ARG_ENABLE(verbose,
 
 AC_ARG_ENABLE(verbose_jtag_io,
   AS_HELP_STRING([--enable-verbose-jtag-io],
-      [Enable verbose JTAG I/O messages (for debugging).]), 
+      [Enable verbose JTAG I/O messages (for debugging).]),
   [debug_jtag_io=$enableval], [])
 AC_ARG_ENABLE(verbose_usb_io,
   AS_HELP_STRING([--enable-verbose-usb-io],
-      [Enable verbose USB I/O messages (for debugging)]), 
+      [Enable verbose USB I/O messages (for debugging)]),
   [debug_usb_io=$enableval], [])
 AC_ARG_ENABLE(verbose_usb_comms,
   AS_HELP_STRING([--enable-verbose-usb-comms],
-      [Enable verbose USB communication messages (for debugging)]), 
+      [Enable verbose USB communication messages (for debugging)]),
   [debug_usb_comms=$enableval], [])
 
 AC_MSG_CHECKING([whether to enable verbose JTAG I/O messages]);
@@ -287,7 +287,7 @@ fi
 debug_malloc=no
 AC_ARG_ENABLE(malloc_logging,
   AS_HELP_STRING([--enable-malloc-logging],
-      [Include free space in logging messages (requires malloc.h).]), 
+      [Include free space in logging messages (requires malloc.h).]),
   [debug_malloc=$enableval], [])
 
 AC_MSG_CHECKING([whether to enable malloc free space logging]);
@@ -298,67 +298,67 @@ fi
 
 
 AC_ARG_ENABLE(dummy,
-  AS_HELP_STRING([--enable-dummy], [Enable building the dummy port driver]), 
+  AS_HELP_STRING([--enable-dummy], [Enable building the dummy port driver]),
   [build_dummy=$enableval], [build_dummy=no])
 
 AC_ARG_ENABLE(parport,
-  AS_HELP_STRING([--enable-parport], [Enable building the pc parallel port driver]), 
+  AS_HELP_STRING([--enable-parport], [Enable building the pc parallel port driver]),
   [build_parport=$enableval], [build_parport=no])
 
 AC_ARG_ENABLE(parport_ppdev,
   AS_HELP_STRING([--disable-parport-ppdev],
-      [Disable use of ppdev (/dev/parportN) for parport (for x86 only)]), 
+      [Disable use of ppdev (/dev/parportN) for parport (for x86 only)]),
     [parport_use_ppdev=$enableval], [parport_use_ppdev=yes])
 
 AC_ARG_ENABLE(parport_giveio,
     AS_HELP_STRING([--enable-parport-giveio],
-      [Enable use of giveio for parport (for CygWin only)]), 
+      [Enable use of giveio for parport (for CygWin only)]),
     [parport_use_giveio=$enableval], [parport_use_giveio=])
-    
+
 AC_ARG_ENABLE(ft2232_libftdi,
-  AS_HELP_STRING([--enable-ft2232_libftdi], [Enable building support for FT2232 based devices using the libftdi driver, opensource alternate of FTD2XX]), 
+  AS_HELP_STRING([--enable-ft2232_libftdi], [Enable building support for FT2232 based devices using the libftdi driver, opensource alternate of FTD2XX]),
   [build_ft2232_libftdi=$enableval], [build_ft2232_libftdi=no])
 
 AC_ARG_ENABLE(ft2232_ftd2xx,
-  AS_HELP_STRING([--enable-ft2232_ftd2xx], [Enable building support for FT2232 based devices using the FTD2XX driver from ftdichip.com]), 
+  AS_HELP_STRING([--enable-ft2232_ftd2xx], [Enable building support for FT2232 based devices using the FTD2XX driver from ftdichip.com]),
   [build_ft2232_ftd2xx=$enableval], [build_ft2232_ftd2xx=no])
 
-AC_ARG_ENABLE(ftd2xx_highspeed,
-  AS_HELP_STRING([--enable-ftd2xx-highspeed], [Enable building support for FT2232H and FT4232H-based devices (requires >=libftd2xx-0.4.16)]), 
-  [want_ftd2xx_highspeed=$enableval], [want_ftd2xx_highspeed=no])
- 
+AC_ARG_ENABLE(ft2232_highspeed,
+  AS_HELP_STRING([--enable-ft2232-highspeed], [Enable building support for FT2232H and FT4232H-based devices (requires >=libftd2xx-0.4.16 or >=libftdi-0.16)]),
+  [want_ft2232_highspeed=$enableval], [want_ft2232_highspeed=no])
+
 AC_ARG_ENABLE(amtjtagaccel,
-  AS_HELP_STRING([--enable-amtjtagaccel], [Enable building the Amontec JTAG-Accelerator driver]), 
+  AS_HELP_STRING([--enable-amtjtagaccel], [Enable building the Amontec JTAG-Accelerator driver]),
   [build_amtjtagaccel=$enableval], [build_amtjtagaccel=no])
 
 AC_ARG_ENABLE(ecosboard,
-  AS_HELP_STRING([--enable-ecosboard], [Enable building support for eCos based JTAG debugger]), 
+  AS_HELP_STRING([--enable-ecosboard], [Enable building support for eCos based JTAG debugger]),
   [build_ecosboard=$enableval], [build_ecosboard=no])
 
 AC_ARG_ENABLE(zy1000,
-  AS_HELP_STRING([--enable-zy1000], [Enable ZY1000 interface]), 
+  AS_HELP_STRING([--enable-zy1000], [Enable ZY1000 interface]),
   [build_zy1000=$enableval], [build_zy1000=no])
 
 AC_ARG_ENABLE(ioutil,
-  AS_HELP_STRING([--enable-ioutil], [Enable ioutil functions - useful for standalone OpenOCD implementations]), 
+  AS_HELP_STRING([--enable-ioutil], [Enable ioutil functions - useful for standalone OpenOCD implementations]),
   [build_ioutil=$enableval], [build_ioutil=no])
 
 AC_ARG_ENABLE(httpd,
-  AS_HELP_STRING([--enable-httpd], [Enable builtin httpd server - useful for standalone OpenOCD implementations]), 
+  AS_HELP_STRING([--enable-httpd], [Enable builtin httpd server - useful for standalone OpenOCD implementations]),
   [build_httpd=$enableval], [build_httpd=no])
 
-case "${host_cpu}" in 
+case "${host_cpu}" in
   arm*)
     AC_ARG_ENABLE(ep93xx,
-      AS_HELP_STRING([--enable-ep93xx], [Enable building support for EP93xx based SBCs]), 
+      AS_HELP_STRING([--enable-ep93xx], [Enable building support for EP93xx based SBCs]),
       [build_ep93xx=$enableval], [build_ep93xx=no])
 
     AC_ARG_ENABLE(at91rm9200,
       AS_HELP_STRING([--enable-at91rm9200], [Enable building support for AT91RM9200 based SBCs]),
       [build_at91rm9200=$enableval], [build_at91rm9200=no])
     ;;
-    
-  *) 
+
+  *)
     build_ep93xx=no
     build_at91rm9200=no
     ;;
@@ -439,10 +439,10 @@ else
   AC_MSG_RESULT([yes])
 fi
 
-case "${host_cpu}" in 
+case "${host_cpu}" in
   i?86|x86*)
     ;;
-  *) 
+  *)
     if test x$parport_use_ppdev = xno; then
       AC_MSG_WARN([--disable-parport-ppdev is not supported by the host CPU])
     fi
@@ -450,8 +450,8 @@ case "${host_cpu}" in
     ;;
 esac
 
-case $host in 
-  *-cygwin*) 
+case $host in
+  *-cygwin*)
     is_win32=yes
     parport_use_ppdev=no
 
@@ -472,11 +472,11 @@ case $host in
         AC_CHECK_HEADERS(sys/io.h,[],AC_MSG_ERROR([Please install the cygwin ioperm package]))
       fi
     fi
-  
+
     AC_DEFINE(IS_WIN32, 1, [1 if building for Win32.])
     AC_DEFINE(IS_DARWIN, 0, [0 if not building for Darwin.])
-    ;; 
-  *-mingw*) 
+    ;;
+  *-mingw*)
     is_mingw=yes
     is_win32=yes
     parport_use_ppdev=no
@@ -489,7 +489,7 @@ case $host in
     AC_DEFINE(IS_MINGW, 1, [1 if building for MinGW.])
     AC_DEFINE(IS_WIN32, 1, [1 if building for Win32.])
     AC_DEFINE(IS_DARWIN, 0, [0 if not building for Darwin.])
-    ;; 
+    ;;
   *darwin*)
     is_darwin=yes
 
@@ -502,7 +502,7 @@ case $host in
     AC_DEFINE(IS_WIN32, 0, [0 if not building for Win32.])
     AC_DEFINE(IS_DARWIN, 1, [1 if building for Darwin.])
     ;;
-  *) 
+  *)
     if test x$parport_use_giveio = xyes; then
       AC_MSG_WARN([--enable-parport-giveio cannot be used by ]$host[ hosts])
     fi
@@ -835,8 +835,8 @@ main( int argc, char **argv )
   ])
 
 AC_MSG_CHECKING([whether to build ftd2xx highspeed device support])
-AC_MSG_RESULT([$want_ftd2xx_highspeed])
-if test $want_ftd2xx_highspeed != no; then
+AC_MSG_RESULT([$want_ft2232_highspeed])
+if test $want_ft2232_highspeed != no; then
   AC_MSG_CHECKING([for ftd2xx highspeed device support])
   AC_COMPILE_IFELSE([
 #include "confdefs.h"
@@ -847,15 +847,15 @@ if test $want_ftd2xx_highspeed != no; then
 #include <ftd2xx.h>
 DWORD x = FT_DEVICE_4232H;
     ], [
-      AC_DEFINE(BUILD_FTD2XX_HIGHSPEED, [1],
-        [Support FT2232H/FT4232HS with FTD2XX.])
-      build_ftd2xx_highspeed=yes
+      AC_DEFINE(BUILD_FT2232_HIGHSPEED, [1],
+        [Support FT2232H/FT4232HS with FTD2XX or libftdi.])
+      build_ft2232_highspeed=yes
     ], [
-      build_ftd2xx_highspeed=no
+      build_ft2232_highspeed=no
     ])
-  AC_MSG_RESULT([$build_ftd2xx_highspeed])
+  AC_MSG_RESULT([$build_ft2232_highspeed])
 
-  if test $want_ftd2xx_highspeed = yes -a $build_ftd2xx_highspeed = no; then
+  if test $want_ft2232_highspeed = yes -a $build_ft2232_highspeed = no; then
     AC_MSG_ERROR([You need a newer FTD2XX driver (version 0.4.16 or later).])
   fi
 fi
@@ -868,7 +868,7 @@ if test $build_ft2232_libftdi = yes ; then
   # We assume: the package is preinstalled in the proper place
   # these present as 2 libraries..
   LIBS="$LIBS -lftdi -lusb"
-  # 
+  #
   # Try to build a small program.
   AC_MSG_CHECKING([Build & Link with libftdi...])
 
@@ -903,6 +903,28 @@ main( int argc, char **argv )
       AC_MSG_RESULT([Skipping as we are cross-compiling])
     ])
 
+  AC_MSG_CHECKING([whether to build libftdi highspeed device support])
+  AC_MSG_RESULT([$want_ft2232_highspeed])
+  if test $want_ft2232_highspeed != no; then
+    AC_MSG_CHECKING([for libftdi highspeed device support])
+    AC_COMPILE_IFELSE([
+#include <stdio.h>
+#include <ftdi.h>
+enum ftdi_chip_type x = TYPE_2232H;
+    ], [
+      AC_DEFINE(BUILD_FT2232_HIGHSPEED, [1],
+        [Support FT2232H/FT4232HS with FTD2XX or libftdi.])
+      build_ft2232_highspeed=yes
+    ], [
+      build_ft2232_highspeed=no
+    ])
+    AC_MSG_RESULT([$build_ft2232_highspeed])
+
+    if test $want_ft2232_highspeed = yes -a $build_ft2232_highspeed = no; then
+      AC_MSG_ERROR([You need a newer libftdi version (0.16 or later).])
+    fi
+  fi
+
   # Restore the 'unexpanded ldflags'
   LDFLAGS=$LDFLAGS_SAVE
   CFLAGS=$CFLAGS_SAVE
@@ -911,7 +933,7 @@ fi
 # check for usb.h when a driver will require it
 if test $build_jlink = yes -o $build_vsllink = yes -o $build_usbprog = yes -o \
   $build_rlink = yes -o $build_armjtagew = yes
-then 
+then
   AC_CHECK_HEADERS([usb.h],[],
   [AC_MSG_ERROR([usb.h is required to build some OpenOCD driver(s)])])
 fi
@@ -976,7 +998,7 @@ int main(int argc, char **argv) { char **ep = environ; }
   ])
 
 if test "${has_environ}" != "yes" ; then
-  AC_MSG_FAILURE([Could not find 'environ' in unistd.h or available libraries.]) 
+  AC_MSG_FAILURE([Could not find 'environ' in unistd.h or available libraries.])
 fi
 
 AC_DEFINE([_GNU_SOURCE],[1],[Use GNU C library extensions (e.g. stdndup).])
diff --git a/src/jtag/ft2232.c b/src/jtag/ft2232.c
index e17d51d6..0806c90a 100644
--- a/src/jtag/ft2232.c
+++ b/src/jtag/ft2232.c
@@ -24,7 +24,6 @@
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
 
-
 /* This code uses information contained in the MPSSE specification which was
  * found here:
  * http://www.ftdichip.com/Documents/AppNotes/AN2232C-01_MPSSE_Cmnd.pdf
@@ -34,7 +33,6 @@
  * http://www.ftdichip.com/Documents/DataSheets/DS_FT2232D.pdf
  */
 
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -65,6 +63,10 @@
 
 /* max TCK for the high speed devices 30000 kHz */
 #define	FTDI_2232H_4232H_MAX_TCK	30000
+/* max TCK for the full speed devices 6000 kHz */
+#define	FTDI_2232C_MAX_TCK 6000
+/* this speed value tells that RTCK is requested */
+#define RTCK_SPEED -1
 
 static int ft2232_execute_queue(void);
 
@@ -81,7 +83,6 @@ static int ft2232_handle_layout_command(struct command_context_s* cmd_ctx, char*
 static int ft2232_handle_vid_pid_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc);
 static int ft2232_handle_latency_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc);
 
-
 /**
  * Send out \a num_cycles on the TCK line while the TAP(s) are in a
  * stable state.  Calling code must ensure that current state is stable,
@@ -94,16 +95,12 @@ static int ft2232_handle_latency_command(struct command_context_s* cmd_ctx, char
  */
 static int ft2232_stableclocks(int num_cycles, jtag_command_t* cmd);
 
-/* max TCK for the high speed devices 30000 kHz */
-#define	FTDI_2232H_4232H_MAX_TCK	30000
-
 static char *       ft2232_device_desc_A = NULL;
 static char*        ft2232_device_desc = NULL;
 static char*        ft2232_serial  = NULL;
 static char*        ft2232_layout  = NULL;
 static uint8_t		ft2232_latency = 2;
-static unsigned		ft2232_max_tck = 6000;
-
+static unsigned		ft2232_max_tck = FTDI_2232C_MAX_TCK;
 
 #define MAX_USB_IDS 8
 /* vid = pid = 0 marks the end of the list */
@@ -182,13 +179,12 @@ static FT_HANDLE	ftdih = NULL;
 static FT_DEVICE	ftdi_device = 0;
 #elif BUILD_FT2232_LIBFTDI == 1
 static struct ftdi_context ftdic;
+static enum ftdi_chip_type ftdi_device;
 #endif
 
-
 static jtag_command_t* first_unsent;        /* next command that has to be sent */
 static int             require_send;
 
-
 /*	http://urjtag.wiki.sourceforge.net/Cable + FT2232 says:
 
 	"There is a significant difference between libftdi and libftd2xx. The latter
@@ -232,7 +228,6 @@ static inline uint8_t buffer_read(void)
 	return ft2232_buffer[ft2232_read_pointer++];
 }
 
-
 /**
  * Clocks out \a bit_count bits on the TMS line, starting with the least
  * significant bit of tms_bits and progressing to more significant bits.
@@ -258,7 +253,9 @@ static void clock_tms(uint8_t mpsse_cmd, int tms_bits, int tms_count, bool tdi_b
 
 	assert(tms_count > 0);
 
-//	LOG_DEBUG("mpsse cmd=%02x, tms_bits = 0x%08x, bit_count=%d", mpsse_cmd, tms_bits, tms_count);
+#if 0
+	LOG_DEBUG("mpsse cmd=%02x, tms_bits = 0x%08x, bit_count=%d", mpsse_cmd, tms_bits, tms_count);
+#endif
 
 	for (tms_byte = tms_ndx = i = 0;   i < tms_count;   ++i, tms_bits>>=1)
 	{
@@ -288,7 +285,6 @@ static void clock_tms(uint8_t mpsse_cmd, int tms_bits, int tms_count, bool tdi_b
 	}
 }
 
-
 /**
  * Function get_tms_buffer_requirements
  * returns what clock_tms() will consume if called with
@@ -299,7 +295,6 @@ static inline int get_tms_buffer_requirements(int bit_count)
 	return ((bit_count + 6)/7) * 3;
 }
 
-
 /**
  * Function move_to_state
  * moves the TAP controller from the current state to a
@@ -326,7 +321,6 @@ static void move_to_state(tap_state_t goal_state)
 	clock_tms(0x4b,  tms_bits, tms_count, 0);
 }
 
-
 jtag_interface_t ft2232_interface =
 {
 	.name			= "ft2232",
@@ -343,7 +337,7 @@ static int ft2232_write(uint8_t* buf, int size, uint32_t* bytes_written)
 {
 #if BUILD_FT2232_FTD2XX == 1
 	FT_STATUS status;
-	DWORD	dw_bytes_written;
+	DWORD dw_bytes_written;
 	if ((status = FT_Write(ftdih, buf, size, &dw_bytes_written)) != FT_OK)
 	{
 		*bytes_written = dw_bytes_written;
@@ -371,13 +365,12 @@ static int ft2232_write(uint8_t* buf, int size, uint32_t* bytes_written)
 #endif
 }
 
-
 static int ft2232_read(uint8_t* buf, uint32_t size, uint32_t* bytes_read)
 {
 #if BUILD_FT2232_FTD2XX == 1
-	DWORD     dw_bytes_read;
+	DWORD dw_bytes_read;
 	FT_STATUS status;
-	int       timeout = 5;
+	int timeout = 5;
 	*bytes_read = 0;
 
 	while ((*bytes_read < size) && timeout--)
@@ -421,58 +414,87 @@ static int ft2232_read(uint8_t* buf, uint32_t size, uint32_t* bytes_read)
 	return ERROR_OK;
 }
 
-#ifdef BUILD_FTD2XX_HIGHSPEED
 static bool ft2232_device_is_highspeed(void)
 {
+#ifdef BUILD_FT2232_HIGHSPEED
+	#if BUILD_FT2232_FTD2XX == 1
 	return (ftdi_device == FT_DEVICE_2232H) || (ftdi_device == FT_DEVICE_4232H);
+	#elif BUILD_FT2232_LIBFTDI == 1
+	return (ftdi_device == TYPE_2232H || ftdi_device == TYPE_4232H);
+	#endif
+#else
+	return false;
+#endif
 }
 
-static int ft2232_adaptive_clocking(int speed)
-{
-	bool use_adaptive_clocking = FALSE;
-	if (0 == speed)
-	{
-		if (ft2232_device_is_highspeed())
-			use_adaptive_clocking = TRUE;
-		else
-		{
-			LOG_ERROR("ft2232 device %lu does not support RTCK", ftdi_device);
-			return ERROR_OK;
-		}
-	}
+/*
+ * Commands that only apply to the FT2232H and FT4232H devices.
+ * See chapter 6 in http://www.ftdichip.com/Documents/AppNotes/
+ * AN_108_Command_Processor_for_MPSSE_and_MCU_Host_Bus_Emulation_Modes.pdf
+ */
 
-	uint8_t  buf = use_adaptive_clocking ? 0x96 : 0x97;
+static int ft2232h_ft4232h_adaptive_clocking(bool enable)
+{
+	uint8_t buf = enable ? 0x96 : 0x97;
 	LOG_DEBUG("%2.2x", buf);
 
 	uint32_t bytes_written;
 	int retval = ft2232_write(&buf, 1, &bytes_written);
-	if (ERROR_OK != retval || bytes_written != 1)
+	if ((ERROR_OK != retval) || (bytes_written != 1))
 	{
-		LOG_ERROR("unable to set adative clocking: %d", retval);
+		LOG_ERROR("couldn't write command to %s adaptive clocking"
+			, enable ? "enable" : "disable");
 		return retval;
 	}
 
 	return ERROR_OK;
 }
-#else
-static int ft2232_adaptive_clocking(int speed)
+
+/**
+ * Enable/disable the clk divide by 5 of the 60MHz master clock.
+ * This result in a JTAG clock speed range of 91.553Hz-6MHz
+ * respective 457.763Hz-30MHz.
+ */
+static int ft2232h_ft4232h_clk_divide_by_5(bool enable)
 {
-	// not implemented on low-speed devices
-	return speed ? ERROR_OK : -1234;
+	uint32_t bytes_written;
+	uint8_t buf = enable ?  0x8b : 0x8a;
+	int retval = ft2232_write(&buf, 1, &bytes_written);
+	if ((ERROR_OK != retval) || (bytes_written != 1))
+	{
+		LOG_ERROR("couldn't write command to %s clk divide by 5"
+			, enable ? "enable" : "disable");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+	ft2232_max_tck = enable ? FTDI_2232C_MAX_TCK : FTDI_2232H_4232H_MAX_TCK;
+	LOG_INFO("max TCK change to: %u kHz", ft2232_max_tck);
+
+	return ERROR_OK;
 }
-#endif
 
 static int ft2232_speed(int speed)
 {
-	uint8_t  buf[3];
+	uint8_t buf[3];
 	int retval;
 	uint32_t bytes_written;
 
-	ft2232_adaptive_clocking(speed);
+	retval = ERROR_OK;
+	bool enable_adaptive_clocking = (RTCK_SPEED == speed);
+	if (ft2232_device_is_highspeed())
+		retval = ft2232h_ft4232h_adaptive_clocking(enable_adaptive_clocking);
+	else if (enable_adaptive_clocking)
+	{
+		LOG_ERROR("ft2232 device %lu does not support RTCK"
+			, (long unsigned int)ftdi_device);
+		return ERROR_FAIL;
+	}
+
+	if ((enable_adaptive_clocking) || (ERROR_OK != retval))
+		return retval;
 
-	buf[0] = 0x86;			/* command "set divisor" */
-	buf[1] = speed & 0xff;          /* valueL (0 = 6MHz, 1 = 3MHz, 2 = 2.0MHz, ...*/
-	buf[2] = (speed >> 8) & 0xff;   /* valueH */
+	buf[0] = 0x86;					/* command "set divisor" */
+	buf[1] = speed & 0xff;			/* valueL (0 = 6MHz, 1 = 3MHz, 2 = 2.0MHz, ...*/
+	buf[2] = (speed >> 8) & 0xff;	/* valueH */
 
 	LOG_DEBUG("%2.2x %2.2x %2.2x", buf[0], buf[1], buf[2]);
 	if (((retval = ft2232_write(buf, 3, &bytes_written)) != ERROR_OK) || (bytes_written != 3))
@@ -484,32 +506,35 @@ static int ft2232_speed(int speed)
 	return ERROR_OK;
 }
 
-
 static int ft2232_speed_div(int speed, int* khz)
 {
 	/* Take a look in the FT2232 manual,
 	 * AN2232C-01 Command Processor for
 	 * MPSSE and MCU Host Bus. Chapter 3.8 */
 
-	*khz = ft2232_max_tck / (1 + speed);
+	*khz = (RTCK_SPEED == speed) ? 0 : ft2232_max_tck / (1 + speed);
 
 	return ERROR_OK;
 }
 
-
 static int ft2232_khz(int khz, int* jtag_speed)
 {
 	if (khz == 0)
 	{
-#ifdef BUILD_FTD2XX_HIGHSPEED
-		*jtag_speed = 0;
-		return ERROR_OK;
-#else
-		LOG_DEBUG("RCLK not supported");
-		LOG_DEBUG("If you have a high-speed FTDI device, then "
-			"OpenOCD may be built with --enable-ftd2xx-highspeed.");
-		return ERROR_FAIL;
+		if (ft2232_device_is_highspeed())
+		{
+			*jtag_speed = RTCK_SPEED;
+			return ERROR_OK;
+		}
+		else
+		{
+			LOG_DEBUG("RCLK not supported");
+#ifndef BUILD_FT2232_HIGHSPEED
+			LOG_DEBUG("If you have a high-speed FTDI device, then "
+				"OpenOCD may be built with --enable-ft2232-highspeed.");
 #endif
+			return ERROR_FAIL;
+		}
 	}
 
 	/* Take a look in the FT2232 manual,
@@ -544,7 +569,6 @@ static int ft2232_khz(int khz, int* jtag_speed)
 	return ERROR_OK;
 }
 
-
 static int ft2232_register_commands(struct command_context_s* cmd_ctx)
 {
 	register_command(cmd_ctx, NULL, "ft2232_device_desc", ft2232_handle_device_desc_command,
@@ -560,7 +584,6 @@ static int ft2232_register_commands(struct command_context_s* cmd_ctx)
 	return ERROR_OK;
 }
 
-
 static void ft2232_end_state(tap_state_t state)
 {
 	if (tap_is_state_stable(state))
@@ -595,11 +618,10 @@ static void ft2232_read_scan(enum scan_type type, uint8_t* buffer, int scan_size
 	buffer[cur_byte] = (buffer[cur_byte] | (((buffer_read()) << 1) & 0x80)) >> (8 - bits_left);
 }
 
-
 static void ft2232_debug_dump_buffer(void)
 {
-	int   i;
-	char  line[256];
+	int i;
+	char line[256];
 	char* line_p = line;
 
 	for (i = 0; i < ft2232_buffer_size; i++)
@@ -616,16 +638,15 @@ static void ft2232_debug_dump_buffer(void)
 		LOG_DEBUG("%s", line);
 }
 
-
 static int ft2232_send_and_recv(jtag_command_t* first, jtag_command_t* last)
 {
 	jtag_command_t* cmd;
-	uint8_t*             buffer;
-	int             scan_size;
+	uint8_t* buffer;
+	int scan_size;
 	enum scan_type  type;
-	int             retval;
-	uint32_t             bytes_written = 0;
-	uint32_t             bytes_read = 0;
+	int retval;
+	uint32_t bytes_written = 0;
+	uint32_t bytes_read = 0;
 
 #ifdef _DEBUG_USB_IO_
 	struct timeval  start, inter, inter2, end;
@@ -735,7 +756,6 @@ static int ft2232_send_and_recv(jtag_command_t* first, jtag_command_t* last)
 	return retval;
 }
 
-
 /**
  * Function ft2232_add_pathmove
  * moves the TAP controller from the current state to a new state through the
@@ -777,7 +797,6 @@ static void ft2232_add_pathmove(tap_state_t* path, int num_states)
 	tap_set_end_state(tap_get_state());
 }
 
-
 static void ft2232_add_scan(bool ir_scan, enum scan_type type, uint8_t* buffer, int scan_size)
 {
 	int num_bytes = (scan_size + 7) / 8;
@@ -936,7 +955,6 @@ static void ft2232_add_scan(bool ir_scan, enum scan_type type, uint8_t* buffer,
 	}
 }
 
-
 static int ft2232_large_scan(scan_command_t* cmd, enum scan_type type, uint8_t* buffer, int scan_size)
 {
 	int num_bytes = (scan_size + 7) / 8;
@@ -1151,7 +1169,6 @@ static int ft2232_large_scan(scan_command_t* cmd, enum scan_type type, uint8_t*
 	return ERROR_OK;
 }
 
-
 static int ft2232_predict_scan_out(int scan_size, enum scan_type type)
 {
 	int predicted_size = 3;
@@ -1160,7 +1177,7 @@ static int ft2232_predict_scan_out(int scan_size, enum scan_type type)
 	if (tap_get_state() != TAP_DRSHIFT)
 		predicted_size += get_tms_buffer_requirements(tap_get_tms_path_len(tap_get_state(), TAP_DRSHIFT));
 
-	if (type == SCAN_IN)    /* only from device to host */
+	if (type == SCAN_IN)	/* only from device to host */
 	{
 		/* complete bytes */
 		predicted_size += CEIL(num_bytes, 65536) * 3;
@@ -1168,7 +1185,7 @@ static int ft2232_predict_scan_out(int scan_size, enum scan_type type)
 		/* remaining bits - 1 (up to 7) */
 		predicted_size += ((scan_size - 1) % 8) ? 2 : 0;
 	}
-	else                    /* host to device, or bidirectional */
+	else	/* host to device, or bidirectional */
 	{
 		/* complete bytes */
 		predicted_size += num_bytes + CEIL(num_bytes, 65536) * 3;
@@ -1180,7 +1197,6 @@ static int ft2232_predict_scan_out(int scan_size, enum scan_type type)
 	return predicted_size;
 }
 
-
 static int ft2232_predict_scan_in(int scan_size, enum scan_type type)
 {
 	int predicted_size = 0;
@@ -1202,38 +1218,37 @@ static int ft2232_predict_scan_in(int scan_size, enum scan_type type)
 	return predicted_size;
 }
 
-
 static void usbjtag_reset(int trst, int srst)
 {
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
 	if (trst == 1)
 	{
 		if (jtag_reset_config & RESET_TRST_OPEN_DRAIN)
-			low_direction |= nTRSTnOE;  /* switch to output pin (output is low) */
+			low_direction |= nTRSTnOE;	/* switch to output pin (output is low) */
 		else
-			low_output &= ~nTRST;       /* switch output low */
+			low_output &= ~nTRST;		/* switch output low */
 	}
 	else if (trst == 0)
 	{
 		if (jtag_reset_config & RESET_TRST_OPEN_DRAIN)
-			low_direction &= ~nTRSTnOE; /* switch to input pin (high-Z + internal and external pullup) */
+			low_direction &= ~nTRSTnOE;	/* switch to input pin (high-Z + internal and external pullup) */
 		else
-			low_output |= nTRST;        /* switch output high */
+			low_output |= nTRST;		/* switch output high */
 	}
 
 	if (srst == 1)
 	{
 		if (jtag_reset_config & RESET_SRST_PUSH_PULL)
-			low_output &= ~nSRST;       /* switch output low */
+			low_output &= ~nSRST;		/* switch output low */
 		else
-			low_direction |= nSRSTnOE;  /* switch to output pin (output is low) */
+			low_direction |= nSRSTnOE;	/* switch to output pin (output is low) */
 	}
 	else if (srst == 0)
 	{
 		if (jtag_reset_config & RESET_SRST_PUSH_PULL)
-			low_output |= nSRST;        /* switch output high */
+			low_output |= nSRST;		/* switch output high */
 		else
-			low_direction &= ~nSRSTnOE; /* switch to input pin (high-Z) */
+			low_direction &= ~nSRSTnOE;	/* switch to input pin (high-Z) */
 	}
 
 	/* command "set data bits low byte" */
@@ -1242,7 +1257,6 @@ static void usbjtag_reset(int trst, int srst)
 	buffer_write(low_direction);
 }
 
-
 static void jtagkey_reset(int trst, int srst)
 {
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
@@ -1284,7 +1298,6 @@ static void jtagkey_reset(int trst, int srst)
 			high_direction);
 }
 
-
 static void olimex_jtag_reset(int trst, int srst)
 {
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
@@ -1320,7 +1333,6 @@ static void olimex_jtag_reset(int trst, int srst)
 			high_direction);
 }
 
-
 static void axm0432_jtag_reset(int trst, int srst)
 {
 	if (trst == 1)
@@ -1350,7 +1362,6 @@ static void axm0432_jtag_reset(int trst, int srst)
 			high_direction);
 }
 
-
 static void flyswatter_reset(int trst, int srst)
 {
 	if (trst == 1)
@@ -1378,7 +1389,6 @@ static void flyswatter_reset(int trst, int srst)
 	LOG_DEBUG("trst: %i, srst: %i, low_output: 0x%2.2x, low_direction: 0x%2.2x", trst, srst, low_output, low_direction);
 }
 
-
 static void turtle_reset(int trst, int srst)
 {
 	trst = trst;
@@ -1399,7 +1409,6 @@ static void turtle_reset(int trst, int srst)
 	LOG_DEBUG("srst: %i, low_output: 0x%2.2x, low_direction: 0x%2.2x", srst, low_output, low_direction);
 }
 
-
 static void comstick_reset(int trst, int srst)
 {
 	if (trst == 1)
@@ -1428,7 +1437,6 @@ static void comstick_reset(int trst, int srst)
 			high_direction);
 }
 
-
 static void stm32stick_reset(int trst, int srst)
 {
 	if (trst == 1)
@@ -1462,8 +1470,6 @@ static void stm32stick_reset(int trst, int srst)
 			high_direction);
 }
 
-
-
 static void sheevaplug_reset(int trst, int srst)
 {
 	if (trst == 1)
@@ -1485,8 +1491,8 @@ static void sheevaplug_reset(int trst, int srst)
 
 static int ft2232_execute_runtest(jtag_command_t *cmd)
 {
-	int  retval;
-	int             i;
+	int retval;
+	int i;
 	int predicted_size = 0;
 	retval = ERROR_OK;
 
@@ -1549,7 +1555,6 @@ static int ft2232_execute_runtest(jtag_command_t *cmd)
 	return retval;
 }
 
-
 static int ft2232_execute_statemove(jtag_command_t *cmd)
 {
 	int	predicted_size = 0;
@@ -1588,8 +1593,7 @@ static int ft2232_execute_pathmove(jtag_command_t *cmd)
 
 	DEBUG_JTAG_IO("pathmove: %i states, current: %s  end: %s", num_states,
 			tap_state_name(tap_get_state()),
-			tap_state_name(path[num_states-1])
-);
+			tap_state_name(path[num_states-1]));
 
 	/* only send the maximum buffer size that FT2232C can handle */
 	predicted_size = 3 * CEIL(num_states, 7);
@@ -1608,13 +1612,12 @@ static int ft2232_execute_pathmove(jtag_command_t *cmd)
 	return retval;
 }
 
-
 static int ft2232_execute_scan(jtag_command_t *cmd)
 {
-	uint8_t*             buffer;
-	int             scan_size;                  /* size of IR or DR scan */
-	int             predicted_size = 0;
-	int				retval = ERROR_OK;
+	uint8_t* buffer;
+	int scan_size;				/* size of IR or DR scan */
+	int predicted_size = 0;
+	int retval = ERROR_OK;
 
 	enum scan_type  type = jtag_scan_type(cmd->cmd.scan);
 
@@ -1667,8 +1670,8 @@ static int ft2232_execute_scan(jtag_command_t *cmd)
 
 static int ft2232_execute_reset(jtag_command_t *cmd)
 {
-	int             retval;
-	int             predicted_size = 0;
+	int retval;
+	int predicted_size = 0;
 	retval = ERROR_OK;
 
 	DEBUG_JTAG_IO("reset trst: %i srst %i",
@@ -1695,7 +1698,7 @@ static int ft2232_execute_reset(jtag_command_t *cmd)
 
 static int ft2232_execute_sleep(jtag_command_t *cmd)
 {
-	int             retval;
+	int retval;
 	retval = ERROR_OK;
 
 	DEBUG_JTAG_IO("sleep %i", cmd->cmd.sleep->us);
@@ -1713,7 +1716,7 @@ static int ft2232_execute_sleep(jtag_command_t *cmd)
 
 static int ft2232_execute_stableclocks(jtag_command_t *cmd)
 {
-	int             retval;
+	int retval;
 	retval = ERROR_OK;
 
 	/* this is only allowed while in a stable state.  A check for a stable
@@ -1730,7 +1733,7 @@ static int ft2232_execute_stableclocks(jtag_command_t *cmd)
 
 static int ft2232_execute_command(jtag_command_t *cmd)
 {
-	int             retval;
+	int retval;
 	retval = ERROR_OK;
 
 	switch (cmd->type)
@@ -1751,10 +1754,10 @@ static int ft2232_execute_command(jtag_command_t *cmd)
 
 static int ft2232_execute_queue()
 {
-	jtag_command_t* cmd = jtag_command_queue;   /* currently processed command */
-	int             retval;
+	jtag_command_t* cmd = jtag_command_queue;	/* currently processed command */
+	int retval;
 
-	first_unsent = cmd;         /* next command that has to be sent */
+	first_unsent = cmd;		/* next command that has to be sent */
 	require_send = 0;
 
 	/* return ERROR_OK, unless ft2232_send_and_recv reports a failed check
@@ -1790,7 +1793,6 @@ static int ft2232_execute_queue()
 	return retval;
 }
 
-
 #if BUILD_FT2232_FTD2XX == 1
 static int ft2232_init_ftd2xx(uint16_t vid, uint16_t pid, int more, int* try_more)
 {
@@ -1838,18 +1840,18 @@ static int ft2232_init_ftd2xx(uint16_t vid, uint16_t pid, int more, int* try_mor
 
 	status = FT_OpenEx(openex_string, openex_flags, &ftdih);
 	if (status != FT_OK) {
-		// under Win32, the FTD2XX driver appends an "A" to the end
-		// of the description, if we tried by the desc, then
-		// try by the alternate "A" description.
+		/* under Win32, the FTD2XX driver appends an "A" to the end
+		 * of the description, if we tried by the desc, then
+		 * try by the alternate "A" description. */
 		if (openex_string == ft2232_device_desc) {
-			// Try the alternate method.
+			/* Try the alternate method. */
 			openex_string = ft2232_device_desc_A;
 			status = FT_OpenEx(openex_string, openex_flags, &ftdih);
 			if (status == FT_OK) {
-				// yea, the "alternate" method worked!
+				/* yea, the "alternate" method worked! */
 			} else {
-				// drat, give the user a meaningfull message.
-				// telling the use we tried *BOTH* methods.
+				/* drat, give the user a meaningfull message.
+				 * telling the use we tried *BOTH* methods. */
 				LOG_WARNING("Unable to open FTDI Device tried: '%s' and '%s'\n",
 							ft2232_device_desc,
 							ft2232_device_desc_A);
@@ -1935,24 +1937,20 @@ static int ft2232_init_ftd2xx(uint16_t vid, uint16_t pid, int more, int* try_mor
 	}
 	else
 	{
-		LOG_INFO("device: %lu", ftdi_device);
+		static const char* type_str[] =
+			{"BM", "AM", "100AX", "UNKNOWN", "2232C", "232R", "2232H", "4232H"};
+		unsigned no_of_known_types = sizeof(type_str) / sizeof(type_str[0]) - 1;
+		unsigned type_index = ((unsigned)ftdi_device < no_of_known_types)
+			? ftdi_device : 3;
+		LOG_INFO("device: %lu \"%s\"", ftdi_device, type_str[type_index]);
 		LOG_INFO("deviceID: %lu", deviceID);
 		LOG_INFO("SerialNumber: %s", SerialNumber);
 		LOG_INFO("Description: %s", Description);
-
-#ifdef BUILD_FTD2XX_HIGHSPEED
-		if (ft2232_device_is_highspeed())
-		{
-			ft2232_max_tck = FTDI_2232H_4232H_MAX_TCK;
-			LOG_INFO("max TCK change to: %u kHz", ft2232_max_tck);
-		}
-#endif
 	}
 
 	return ERROR_OK;
 }
 
-
 static int ft2232_purge_ftd2xx(void)
 {
 	FT_STATUS status;
@@ -1966,7 +1964,6 @@ static int ft2232_purge_ftd2xx(void)
 	return ERROR_OK;
 }
 
-
 #endif /* BUILD_FT2232_FTD2XX == 1 */
 
 #if BUILD_FT2232_LIBFTDI == 1
@@ -2024,10 +2021,16 @@ static int ft2232_init_libftdi(uint16_t vid, uint16_t pid, int more, int* try_mo
 
 	ftdi_set_bitmode(&ftdic, 0x0b, 2); /* ctx, JTAG I/O mask */
 
+	ftdi_device = ftdic.type;
+	static const char* type_str[] =
+		{"AM", "BM", "2232C", "R", "2232H", "4232H", "Unknown"};
+	unsigned no_of_known_types = sizeof(type_str) / sizeof(type_str[0]) - 1;
+	unsigned type_index = ((unsigned)ftdi_device < no_of_known_types)
+		? ftdi_device : no_of_known_types;
+	LOG_DEBUG("FTDI chip type: %i \"%s\"", (int)ftdi_device, type_str[type_index]);
 	return ERROR_OK;
 }
 
-
 static int ft2232_purge_libftdi(void)
 {
 	if (ftdi_usb_purge_buffers(&ftdic) < 0)
@@ -2039,7 +2042,6 @@ static int ft2232_purge_libftdi(void)
 	return ERROR_OK;
 }
 
-
 #endif /* BUILD_FT2232_LIBFTDI == 1 */
 
 static int ft2232_init(void)
@@ -2114,6 +2116,12 @@ static int ft2232_init(void)
 	if (layout->init() != ERROR_OK)
 		return ERROR_JTAG_INIT_FAILED;
 
+	if (ft2232_device_is_highspeed())
+	{
+		if (ft2232h_ft4232h_clk_divide_by_5(false) != ERROR_OK)
+			return ERROR_JTAG_INIT_FAILED;
+	}
+
 	ft2232_speed(jtag_get_speed());
 
 	buf[0] = 0x85; /* Disconnect TDI/DO to TDO/DI for Loopback */
@@ -2132,7 +2140,6 @@ static int ft2232_init(void)
 	return ERROR_OK;
 }
 
-
 static int usbjtag_init(void)
 {
 	uint8_t  buf[3];
@@ -2217,7 +2224,6 @@ static int usbjtag_init(void)
 	return ERROR_OK;
 }
 
-
 static int axm0432_jtag_init(void)
 {
 	uint8_t  buf[3];
@@ -2288,7 +2294,6 @@ static int axm0432_jtag_init(void)
 	return ERROR_OK;
 }
 
-
 static int jtagkey_init(void)
 {
 	uint8_t  buf[3];
@@ -2371,7 +2376,6 @@ static int jtagkey_init(void)
 	return ERROR_OK;
 }
 
-
 static int olimex_jtag_init(void)
 {
 	uint8_t  buf[3];
@@ -2439,7 +2443,6 @@ static int olimex_jtag_init(void)
 	return ERROR_OK;
 }
 
-
 static int flyswatter_init(void)
 {
 	uint8_t  buf[3];
@@ -2486,7 +2489,6 @@ static int flyswatter_init(void)
 	return ERROR_OK;
 }
 
-
 static int turtle_init(void)
 {
 	uint8_t  buf[3];
@@ -2527,7 +2529,6 @@ static int turtle_init(void)
 	return ERROR_OK;
 }
 
-
 static int comstick_init(void)
 {
 	uint8_t  buf[3];
@@ -2571,7 +2572,6 @@ static int comstick_init(void)
 	return ERROR_OK;
 }
 
-
 static int stm32stick_init(void)
 {
 	uint8_t  buf[3];
@@ -2615,7 +2615,6 @@ static int stm32stick_init(void)
 	return ERROR_OK;
 }
 
-
 static int sheevaplug_init(void)
 {
 	uint8_t buf[3];
@@ -2731,7 +2730,6 @@ static void olimex_jtag_blink(void)
 	buffer_write(high_direction);
 }
 
-
 static void flyswatter_jtag_blink(void)
 {
 	/*
@@ -2744,7 +2742,6 @@ static void flyswatter_jtag_blink(void)
 	buffer_write(high_direction);
 }
 
-
 static void turtle_jtag_blink(void)
 {
 	/*
@@ -2764,7 +2761,6 @@ static void turtle_jtag_blink(void)
 	buffer_write(high_direction);
 }
 
-
 static int ft2232_quit(void)
 {
 #if BUILD_FT2232_FTD2XX == 1
@@ -2783,7 +2779,6 @@ static int ft2232_quit(void)
 	return ERROR_OK;
 }
 
-
 static int ft2232_handle_device_desc_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc)
 {
 	char *cp;
@@ -2792,20 +2787,20 @@ static int ft2232_handle_device_desc_command(struct command_context_s* cmd_ctx,
 	{
 		ft2232_device_desc = strdup(args[0]);
 		cp = strchr(ft2232_device_desc, 0);
-		// under Win32, the FTD2XX driver appends an "A" to the end
-		// of the description, this examines the given desc
-		// and creates the 'missing' _A or non_A variable.
+		/* under Win32, the FTD2XX driver appends an "A" to the end
+		 * of the description, this examines the given desc
+		 * and creates the 'missing' _A or non_A variable. */
 		if ((cp[-1] == 'A') && (cp[-2]==' ')) {
-			// it was, so make this the "A" version.
+			/* it was, so make this the "A" version. */
 			ft2232_device_desc_A = ft2232_device_desc;
-			// and *CREATE* the non-A version.
+			/* and *CREATE* the non-A version. */
 			strcpy(buf, ft2232_device_desc);
 			cp = strchr(buf, 0);
 			cp[-2] = 0;
 			ft2232_device_desc =  strdup(buf);
 		} else {
-			// <space > A not defined
-			// so create it
+			/* <space > A not defined
+			 * so create it */
 			sprintf(buf, "%s A", ft2232_device_desc);
 			ft2232_device_desc_A = strdup(buf);
 		}
@@ -2818,7 +2813,6 @@ static int ft2232_handle_device_desc_command(struct command_context_s* cmd_ctx,
 	return ERROR_OK;
 }
 
-
 static int ft2232_handle_serial_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc)
 {
 	if (argc == 1)
@@ -2833,7 +2827,6 @@ static int ft2232_handle_serial_command(struct command_context_s* cmd_ctx, char*
 	return ERROR_OK;
 }
 
-
 static int ft2232_handle_layout_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc)
 {
 	if (argc == 0)
@@ -2845,7 +2838,6 @@ static int ft2232_handle_layout_command(struct command_context_s* cmd_ctx, char*
 	return ERROR_OK;
 }
 
-
 static int ft2232_handle_vid_pid_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc)
 {
 	if (argc > MAX_USB_IDS * 2)
@@ -2859,7 +2851,7 @@ static int ft2232_handle_vid_pid_command(struct command_context_s* cmd_ctx, char
 		LOG_WARNING("incomplete ft2232_vid_pid configuration directive");
 		if (argc < 2)
 			return ERROR_COMMAND_SYNTAX_ERROR;
-		// remove the incomplete trailing id
+		/* remove the incomplete trailing id */
 		argc -= 1;
 	}
 
@@ -2884,7 +2876,6 @@ static int ft2232_handle_vid_pid_command(struct command_context_s* cmd_ctx, char
 	return retval;
 }
 
-
 static int ft2232_handle_latency_command(struct command_context_s* cmd_ctx, char* cmd, char** args, int argc)
 {
 	if (argc == 1)
@@ -2899,7 +2890,6 @@ static int ft2232_handle_latency_command(struct command_context_s* cmd_ctx, char
 	return ERROR_OK;
 }
 
-
 static int ft2232_stableclocks(int num_cycles, jtag_command_t* cmd)
 {
 	int retval = 0;
@@ -2942,7 +2932,6 @@ static int ft2232_stableclocks(int num_cycles, jtag_command_t* cmd)
 	return retval;
 }
 
-
 /* ---------------------------------------------------------------------
  * Support for IceBear JTAG adapter from Section5:
  *	http://section5.ch/icebear