Merge remote-tracking branch 'upstream/master' into interleaved_rg

17 files changed, 386 insertions, 48 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b6bcb5b..5fb110f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,6 +22,8 @@
 cmake_minimum_required(VERSION 2.6)
 project(libosmo-fl2k C)
 
+include(GNUInstallDirs)
+
 #select the release build type by default to get optimization flags
 if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE "Release")
@@ -157,7 +159,7 @@ CONFIGURE_FILE(
 
 INSTALL(
     FILES ${CMAKE_CURRENT_BINARY_DIR}/libosmo-fl2k.pc
-    DESTINATION ${LIB_INSTALL_DIR}/pkgconfig
+    DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig
 )
 
 ########################################################################
diff --git a/debian/changelog b/debian/changelog
new file mode 100644
index 0000000..40e26ef
--- /dev/null
+++ b/debian/changelog
@@ -0,0 +1,18 @@
+osmo-fl2k (0.1.0git) unstable; urgency=medium
+
+  * Osmocom debian recipes for nightly builds
+
+ -- Harald Welte <laforge@gnumonks.org>  Sun, 03 Jun 2018 16:13:07 +0200
+
+osmo-fl2k (0.1.0+20180423git9e79bde-2) unstable; urgency=medium
+
+  * debian/control: set team as maintainer
+  * debian/copyright: add some entries (Closes: #896832)
+
+ -- Thorsten Alteholz <debian@alteholz.de>  Wed, 25 Apr 2018 19:28:07 +0200
+
+osmo-fl2k (0.1.0+20180423git9e79bde-1) unstable; urgency=medium
+
+  * Initial release.
+
+ -- Thorsten Alteholz <debian@alteholz.de>  Tue, 24 Apr 2018 18:28:07 +0200
diff --git a/debian/compat b/debian/compat
new file mode 100644
index 0000000..ec63514
--- /dev/null
+++ b/debian/compat
@@ -0,0 +1 @@
+9
diff --git a/debian/control b/debian/control
new file mode 100644
index 0000000..751034c
--- /dev/null
+++ b/debian/control
@@ -0,0 +1,50 @@
+Source: osmo-fl2k
+Section: libs
+Priority: optional
+Maintainer: Debian Mobcom Maintainers <Debian-mobcom-maintainers@lists.alioth.debian.org>
+Uploaders: Thorsten Alteholz <debian@alteholz.de>
+Build-Depends: debhelper (>= 9.0.0~),  dh-autoreconf
+	, pkg-config
+	, cmake
+	, libusb-1.0-0-dev
+Standards-Version: 4.1.4
+Vcs-Browser: https://salsa.debian.org/debian-mobcom-team/osmo-fl2k
+Vcs-Git: https://salsa.debian.org/debian-mobcom-team/osmo-fl2k.git
+Homepage: https://projects.osmocom.org/projects/osmo-fl2k
+
+Package: osmo-fl2k
+Section: net
+Architecture: any
+Multi-Arch: no
+Pre-Depends: ${misc:Pre-Depends}
+Depends: ${misc:Depends}, ${shlibs:Depends}
+Description: use a VGA USB adapter as DAC and SDR transmitter
+ This software allows one to use USB 3.0 to VGA adapters based on the
+ Fresco Logic FL2000 chip as general purpose DACs and SDR transmitter
+ generating a continuous stream of samples by avoiding the HSYNC and
+ VSYNC blanking intervals.
+
+Package: libosmo-fl2k0
+Architecture: any
+Multi-Arch: same
+Pre-Depends: ${misc:Pre-Depends}
+Depends: ${misc:Depends}, ${shlibs:Depends}
+Description: use a VGA USB adapter as DAC and SDR transmitter - library
+ This software allows one to use USB 3.0 to VGA adapters based on the
+ Fresco Logic FL2000 chip as general purpose DACs and SDR transmitter
+ generating a continuous stream of samples by avoiding the HSYNC and
+ VSYNC blanking intervals.
+ .
+ This package provides the shared library.
+
+Package: libosmo-fl2k-dev
+Section: libdevel
+Architecture: any
+Depends: libosmo-fl2k0 (= ${binary:Version}), ${misc:Depends}
+Description: use a VGA USB adapter as DAC and SDR transmitter - development
+ This software allows one to use USB 3.0 to VGA adapters based on the
+ Fresco Logic FL2000 chip as general purpose DACs and SDR transmitter
+ generating a continuous stream of samples by avoiding the HSYNC and
+ VSYNC blanking intervals.
+ .
+ This package provides the development files.
diff --git a/debian/copyright b/debian/copyright
new file mode 100644
index 0000000..a1949b6
--- /dev/null
+++ b/debian/copyright
@@ -0,0 +1,97 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: osmo-fl2k
+Source: git://git.osmocom.org/
+
+Files:     *
+Copyright: 2012-2018 Steve Markgraf <steve@steve-m.de>
+           2009 Bartek Kania <mbk@gnarf.org>
+           2012-2014 Kyle Keen <keenerd@gmail.com>
+           2014 Michael Tatarinov <kukabu@gmail.com>
+License:   GPL-2.0+
+
+Files:     src/rds_mod.c include/rds_mod.h
+Copyright: 2018 Steve Markgraf <steve@steve-m.de>
+           2014 Christophe Jacquet, F8FTK
+License:   GPL-3.0+
+
+Files:     src/rds_waveforms.c
+Copyright: 2014 Christophe Jacquet.
+License:   GPL-3.0
+
+Files:     src/getopt/*
+Copyright: 1987,88,89,90,91,92,93,94,95,96,98,99,2000,2001 Free Software Foundation, Inc.
+License:   LGPL-2.1+
+Comment:   This file is part of the GNU C Library.
+
+License:   LGPL-2.1+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+ .
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+ .
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA.
+ .
+ On Debian systems, the complete text of the GNU Lesser General Public 
+ License Version 2.1 can be found in `/usr/share/common-licenses/LGPL-2.1'.
+
+Files:     debian/*
+Copyright: 2018 Thorsten Alteholz <debian@alteholz.de>
+License:   GPL-2.0+
+
+License:   GPL-2.0+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 2 of the License, or
+ (at your option) any later version.
+ .
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ .
+ On Debian systems, the complete text of the GNU General Public License
+ Version 2 can be found in `/usr/share/common-licenses/GPL-2'.
+
+License:   GPL-3.0+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+ .
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ .
+ On Debian systems, the complete text of the GNU General Public License
+ Version 3 can be found in `/usr/share/common-licenses/GPL-3'.
+
+License:   GPL-3.0
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation in version 3 of the License.
+ .
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ .
+ On Debian systems, the complete text of the GNU General Public License
+ Version 3 can be found in `/usr/share/common-licenses/GPL-3'.
diff --git a/debian/libosmo-fl2k-dev.install b/debian/libosmo-fl2k-dev.install
new file mode 100644
index 0000000..e1bb00c
--- /dev/null
+++ b/debian/libosmo-fl2k-dev.install
@@ -0,0 +1,4 @@
+usr/include/*
+usr/lib/*/pkgconfig/libosmo-fl2k.pc
+usr/lib/*/libosmo-fl2k.a
+usr/lib/*/*.so
diff --git a/debian/libosmo-fl2k0.install b/debian/libosmo-fl2k0.install
new file mode 100644
index 0000000..3de3b10
--- /dev/null
+++ b/debian/libosmo-fl2k0.install
@@ -0,0 +1 @@
+usr/lib/*/*.so.*
diff --git a/debian/osmo-fl2k.install b/debian/osmo-fl2k.install
new file mode 100644
index 0000000..1df36c6
--- /dev/null
+++ b/debian/osmo-fl2k.install
@@ -0,0 +1 @@
+usr/bin/*
diff --git a/debian/rules b/debian/rules
new file mode 100755
index 0000000..74833df
--- /dev/null
+++ b/debian/rules
@@ -0,0 +1,11 @@
+#!/usr/bin/make -f
+
+#export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed
+export DEB_BUILD_MAINT_OPTIONS = hardening=+all
+
+%:
+	dh $@ --with autoreconf
+
+# Print test results in case of a failure
+override_dh_auto_test:
+	dh_auto_test || (find . -name testsuite.log -exec cat {} \; ; false)
diff --git a/debian/source/format b/debian/source/format
new file mode 100644
index 0000000..89ae9db
--- /dev/null
+++ b/debian/source/format
@@ -0,0 +1 @@
+3.0 (native)
diff --git a/debian/watch b/debian/watch
new file mode 100644
index 0000000..f48ad27
--- /dev/null
+++ b/debian/watch
@@ -0,0 +1,3 @@
+version=4
+opts="mode=git, dversionmangle=s/\+ds//" https://git.osmocom.org/osmo-fl2k refs/tags/([\d\.]+) debian uupdate
+
diff --git a/include/osmo-fl2k.h b/include/osmo-fl2k.h
index 6a1b3ee..aefbb8c 100644
--- a/include/osmo-fl2k.h
+++ b/include/osmo-fl2k.h
@@ -37,6 +37,7 @@ enum fl2k_error {
 	FL2K_ERROR_NO_DEVICE = -2,
 	FL2K_ERROR_NOT_FOUND = -5,
 	FL2K_ERROR_BUSY = -6,
+	FL2K_ERROR_TIMEOUT = -7,
 	FL2K_ERROR_NO_MEM = -11,
 };
 
@@ -124,6 +125,40 @@ FL2K_API int fl2k_start_tx(fl2k_dev_t *dev, fl2k_tx_cb_t cb,
  */
 FL2K_API int fl2k_stop_tx(fl2k_dev_t *dev);
 
+/*!
+ * Read 4 bytes via the FL2K I2C bus
+ *
+ * \param dev the device handle given by fl2k_open()
+ * \param i2c_addr address of the I2C device
+ * \param reg_addr start address of the 4 bytes to be read
+ * \param data pointer to byte array of size 4
+ * \return 0 on success
+ * \note A read operation will look like this on the bus:
+ *       START, I2C_ADDR(W), REG_ADDR,   REP_START, I2C_ADDR(R), DATA[0], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+1, REP_START, I2C_ADDR(R), DATA[1], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+2, REP_START, I2C_ADDR(R), DATA[2], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+3, REP_START, I2C_ADDR(R), DATA[3], STOP
+ */
+FL2K_API int fl2k_i2c_read(fl2k_dev_t *dev, uint8_t i2c_addr,
+		           uint8_t reg_addr, uint8_t *data);
+
+/*!
+ * Write 4 bytes via the FL2K I2C bus
+ *
+ * \param dev the device handle given by fl2k_open()
+ * \param i2c_addr address of the I2C device
+ * \param reg_addr start address of the 4 bytes to be written
+ * \param data pointer to byte array of size 4
+ * \return 0 on success
+ * \note A write operation will look like this on the bus:
+ *       START, I2C_ADDR(W), REG_ADDR,   DATA[0], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+1, DATA[1], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+2, DATA[2], STOP
+ *       START, I2C_ADDR(W), REG_ADDR+3, DATA[3], STOP
+ */
+FL2K_API int fl2k_i2c_write(fl2k_dev_t *dev, uint8_t i2c_addr,
+			    uint8_t reg_addr, uint8_t *data);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1d788de..f63780a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -15,6 +15,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+include(GNUInstallDirs)
+
 MACRO(LIBFL2K_APPEND_SRCS)
     LIST(APPEND libosmo-fl2k_srcs ${ARGV})
 ENDMACRO(LIBFL2K_APPEND_SRCS)
@@ -124,7 +126,7 @@ endif()
 # Install built library files & utilities
 ########################################################################
 install(TARGETS ${INSTALL_TARGETS}
-    LIBRARY DESTINATION ${LIB_INSTALL_DIR} # .so/.dylib file
-    ARCHIVE DESTINATION ${LIB_INSTALL_DIR} # .lib file
+    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} # .so/.dylib file
+    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR} # .lib file
     RUNTIME DESTINATION bin              # .dll file
 )
diff --git a/src/fl2k_file.c b/src/fl2k_file.c
index 0da1cbc..2cea6ff 100644
--- a/src/fl2k_file.c
+++ b/src/fl2k_file.c
@@ -28,11 +28,13 @@
 
 #ifndef _WIN32
 #include <unistd.h>
+#define sleep_ms(ms)	usleep(ms*1000)
 #else
 #include <windows.h>
 #include <io.h>
 #include <fcntl.h>
 #include "getopt/getopt.h"
+#define sleep_ms(ms)	Sleep(ms)
 #endif
 
 #include "osmo-fl2k.h"
@@ -156,10 +158,17 @@ int main(int argc, char **argv)
 	if (dev_index < 0)
 		exit(1);
 
-	file = fopen(filename, "rb");
-	if (!file) {
-		fprintf(stderr, "Failed to open %s\n", filename);
-		goto out;
+	if (strcmp(filename, "-") == 0) { /* Read samples from stdin */
+		file = stdin;
+#ifdef _WIN32
+		_setmode(_fileno(stdin), _O_BINARY);
+#endif
+	} else {
+		file = fopen(filename, "rb");
+		if (!file) {
+			fprintf(stderr, "Failed to open %s\n", filename);
+			return -ENOENT;
+		}
 	}
 
 	txbuf = malloc(FL2K_BUF_LEN * (interleaved ? 2 : 1));
@@ -195,13 +204,8 @@ int main(int argc, char **argv)
 	SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
 #endif
 
-	while (!do_exit) {
-#ifndef _WIN32
-		usleep(500000);
-#else
-		Sleep(0.5);
-#endif
-	}
+	while (!do_exit)
+		sleep_ms(500);
 
 	fl2k_close(dev);
 
diff --git a/src/fl2k_tcp.c b/src/fl2k_tcp.c
index ad0aa18..bd01758 100644
--- a/src/fl2k_tcp.c
+++ b/src/fl2k_tcp.c
@@ -36,9 +36,12 @@
 #include <netinet/in.h>
 #include <netinet/tcp.h> /* for TCP_NODELAY */
 #include <fcntl.h>
+#define sleep_ms(ms)	usleep(ms*1000)
 #else
+#include <windows.h>
 #include <winsock2.h>
 #include "getopt/getopt.h"
+#define sleep_ms(ms)	Sleep(ms)
 #endif
 
 #include "osmo-fl2k.h"
@@ -217,11 +220,7 @@ int main(int argc, char **argv)
 
 	fprintf(stderr, "Connecting to %s:%d...\n", addr, port);
 	while (connect(sock, (struct sockaddr *)&remote, sizeof(remote)) != 0) {
-#ifndef _WIN32
-		usleep(500000);
-#else
-		Sleep(0.5);
-#endif
+		sleep_ms(500);
 		if (do_exit)
 			goto out;
 	}
@@ -230,13 +229,8 @@ int main(int argc, char **argv)
 	fprintf(stderr, "Connected\n");
 	connected = 1;
 
-	while (!do_exit) {
-#ifndef _WIN32
-		usleep(500000);
-#else
-		Sleep(0.5);
-#endif
-	}
+	while (!do_exit)
+		sleep_ms(500);
 
 out:
 	free(txbuf);
diff --git a/src/fl2k_test.c b/src/fl2k_test.c
index c9a6048..6d82922 100644
--- a/src/fl2k_test.c
+++ b/src/fl2k_test.c
@@ -41,9 +41,11 @@
 
 #ifndef _WIN32
 #include <unistd.h>
+#define sleep_ms(ms)	usleep(ms*1000)
 #else
 #include <windows.h>
 #include "getopt/getopt.h"
+#define sleep_ms(ms)	Sleep(ms)
 #endif
 
 #include "osmo-fl2k.h"
@@ -290,17 +292,11 @@ int main(int argc, char **argv)
 	fprintf(stderr, "Reporting PPM error measurement every %u seconds...\n", ppm_duration);
 	fprintf(stderr, "Press ^C after a few minutes.\n");
 
-	while (!do_exit) {
-#ifndef _WIN32
-		usleep(500000);
-#else
-		Sleep(0.5);
-#endif
-	}
+	while (!do_exit)
+		sleep_ms(500);
 
-	if (do_exit) {
+	if (do_exit)
 		fprintf(stderr, "\nUser cancel, exiting...\n");
-	}
 
 exit:
 	fl2k_close(dev);
diff --git a/src/libosmo-fl2k.c b/src/libosmo-fl2k.c
index 09380b6..c5959c3 100644
--- a/src/libosmo-fl2k.c
+++ b/src/libosmo-fl2k.c
@@ -25,15 +25,18 @@
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <math.h>
+#include <libusb.h>
+#include <pthread.h>
 
 #ifndef _WIN32
 #include <unistd.h>
+#define sleep_ms(ms)	usleep(ms*1000)
+#else
+#include <windows.h>
+#define sleep_ms(ms)	Sleep(ms)
 #endif
 
-#include <math.h>
-#include <libusb.h>
-#include <pthread.h>
-
 /*
  * All libusb callback functions should be marked with the LIBUSB_CALL macro
  * to ensure that they are compiled with the same calling convention as libusb.
@@ -381,7 +384,11 @@ int fl2k_open(fl2k_dev_t **out_dev, uint32_t index)
 		return -1;
 	}
 
+#if LIBUSB_API_VERSION >= 0x01000106
+	libusb_set_option(dev->ctx, LIBUSB_OPTION_LOG_LEVEL, 3);
+#else
 	libusb_set_debug(dev->ctx, 3);
+#endif
 
 	dev->dev_lost = 1;
 
@@ -472,13 +479,8 @@ int fl2k_close(fl2k_dev_t *dev)
 
 	if(!dev->dev_lost) {
 		/* block until all async operations have been completed (if any) */
-		while (FL2K_INACTIVE != dev->async_status) {
-#ifdef _WIN32
-			Sleep(1);
-#else
-			usleep(1000);
-#endif
-		}
+		while (FL2K_INACTIVE != dev->async_status)
+			sleep_ms(100);
 
 		fl2k_deinit_device(dev);
 	}
@@ -589,11 +591,26 @@ static int fl2k_alloc_submit_transfers(fl2k_dev_t *dev)
 	for (i = 0; i < dev->xfer_buf_num; ++i) {
 		dev->xfer_buf[i] = libusb_dev_mem_alloc(dev->devh, dev->xfer_buf_len);
 
-		if (!dev->xfer_buf[i]) {
+		if (dev->xfer_buf[i]) {
+			/* Check if Kernel usbfs mmap() bug is present: if the
+			 * mapping is correct, the buffers point to memory that
+			 * was memset to 0 by the Kernel, otherwise, they point
+			 * to random memory. We check if the buffers are zeroed
+			 * and otherwise fall back to buffers in userspace.
+			 */
+			if (dev->xfer_buf[i][0] || memcmp(dev->xfer_buf[i],
+							  dev->xfer_buf[i] + 1,
+							  dev->xfer_buf_len - 1)) {
+				fprintf(stderr, "Detected Kernel usbfs mmap() "
+						"bug, falling back to buffers "
+						"in userspace\n");
+				dev->use_zerocopy = 0;
+				break;
+			}
+		} else {
 			fprintf(stderr, "Failed to allocate zero-copy "
 					"buffer for transfer %d\nFalling "
 					"back to buffers in userspace\n", i);
-
 			dev->use_zerocopy = 0;
 			break;
 		}
@@ -1020,3 +1037,104 @@ int fl2k_stop_tx(fl2k_dev_t *dev)
 
 	return FL2K_ERROR_BUSY;
 }
+
+int fl2k_i2c_read(fl2k_dev_t *dev, uint8_t i2c_addr, uint8_t reg_addr, uint8_t *data)
+{
+	int i, r, timeout = 1;
+	uint32_t reg;
+
+	if (!dev)
+		return FL2K_ERROR_INVALID_PARAM;
+
+	r = fl2k_read_reg(dev, 0x8020, &reg);
+	if (r < 0)
+		return r;
+
+	/* apply mask, clearing bit 30 disables periodic repetition of read */
+	reg &= 0x3ffc0000;
+
+	/* set I2C register and address, select I2C read (bit 7) */
+	reg |= (1 << 28) | (reg_addr << 8) | (1 << 7) | (i2c_addr & 0x7f);
+
+	r = fl2k_write_reg(dev, 0x8020, reg);
+	if (r < 0)
+		return r;
+
+	for (i = 0; i < 10; i++) {
+		sleep_ms(10);
+
+		r = fl2k_read_reg(dev, 0x8020, &reg);
+		if (r < 0)
+			return r;
+
+		/* check if operation completed */ 
+		if (reg & (1 << 31)) {
+			timeout = 0;
+			break;
+		}
+	}
+
+	if (timeout)
+		return FL2K_ERROR_TIMEOUT;
+
+	/* check if slave responded and all data was read */
+	if (reg & (0x0f << 24))
+		return FL2K_ERROR_NOT_FOUND;
+
+	/* read data from register 0x8024 */
+	return libusb_control_transfer(dev->devh, CTRL_IN, 0x40,
+				       0, 0x8024, data, 4, CTRL_TIMEOUT);
+}
+
+int fl2k_i2c_write(fl2k_dev_t *dev, uint8_t i2c_addr, uint8_t reg_addr, uint8_t *data)
+{
+	int i, r, timeout = 1;
+	uint32_t reg;
+
+	if (!dev)
+		return FL2K_ERROR_INVALID_PARAM;
+
+	/* write data to register 0x8028 */
+	r = libusb_control_transfer(dev->devh, CTRL_OUT, 0x41,
+				    0, 0x8028, data, 4, CTRL_TIMEOUT);
+
+	if (r < 0)
+		return r;
+
+	r = fl2k_read_reg(dev, 0x8020, &reg);
+	if (r < 0)
+		return r;
+
+	/* apply mask, clearing bit 30 disables periodic repetition of read */
+	reg &= 0x3ffc0000;
+
+	/* set I2C register and address */
+	reg |= (1 << 28) | (reg_addr << 8) | (i2c_addr & 0x7f);
+
+	r = fl2k_write_reg(dev, 0x8020, reg);
+	if (r < 0)
+		return r;
+
+	for (i = 0; i < 10; i++) {
+		sleep_ms(10);
+
+		r = fl2k_read_reg(dev, 0x8020, &reg);
+		if (r < 0)
+			return r;
+
+		/* check if operation completed */ 
+		if (reg & (1 << 31)) {
+			timeout = 0;
+			break;
+		}
+	}
+
+	if (timeout)
+		return FL2K_ERROR_TIMEOUT;
+
+	/* check if slave responded and all data was written */
+	if (reg & (0x0f << 24))
+		return FL2K_ERROR_NOT_FOUND;
+
+	return FL2K_SUCCESS;
+}