I have found this link: 
RE: serial connection with iio oscilloscope
I have followed it:

$ ldd $(which iio_info) 
 linux-vdso.so.1 (0x00007ffe687c1000)
 libiio.so.0 => /lib/x86_64-linux-gnu/libiio.so.0 (0x00007f03d5728000)
 libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f03d5536000)
 libusb-1.0.so.0 => /lib/x86_64-linux-gnu/libusb-1.0.so.0 (0x00007f03d551a000)
 libavahi-client.so.3 => /lib/x86_64-linux-gnu/libavahi-client.so.3 (0x00007f03d5507000)
 libavahi-common.so.3 => /lib/x86_64-linux-gnu/libavahi-common.so.3 (0x00007f03d54f9000)
 libxml2.so.2 => /lib/x86_64-linux-gnu/libxml2.so.2 (0x00007f03d533f000)
 libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f03d531a000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f03d5775000)
 libudev.so.1 => /lib/x86_64-linux-gnu/libudev.so.1 (0x00007f03d52ed000)
 libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f03d529c000)
 libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f03d5296000)
 libicuuc.so.66 => /lib/x86_64-linux-gnu/libicuuc.so.66 (0x00007f03d50b0000)
 libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f03d5094000)
 liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f03d5069000)
 libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f03d4f1a000)
 libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f03d4e6b000)
 libicudata.so.66 => /lib/x86_64-linux-gnu/libicudata.so.66 (0x00007f03d33aa000)
 libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f03d31c8000)
 libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f03d31ad000)
 librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f03d31a1000)
 liblz4.so.1 => /lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f03d3180000)
 libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f03d3062000)
 libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f03d303f000)
I download the libserialport from https://github.com/sigrokproject/libserialport.git

$ cd libserialport-master/
$ ./autogen.sh
autoreconf: Entering directory `.'
autoreconf: configure.ac: not using Gettext
autoreconf: running: aclocal --force -I autostuff
autoreconf: configure.ac: tracing
autoreconf: running: libtoolize --copy --force
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'autostuff'.
libtoolize: copying file 'autostuff/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'autostuff'.
libtoolize: copying file 'autostuff/libtool.m4'
libtoolize: copying file 'autostuff/ltoptions.m4'
libtoolize: copying file 'autostuff/ltsugar.m4'
libtoolize: copying file 'autostuff/ltversion.m4'
libtoolize: copying file 'autostuff/lt~obsolete.m4'
autoreconf: running: /usr/bin/autoconf --force
autoreconf: running: /usr/bin/autoheader --force
autoreconf: running: automake --add-missing --copy --force-missing
configure.ac:46: installing 'autostuff/ar-lib'
configure.ac:46: installing 'autostuff/compile'
configure.ac:67: installing 'autostuff/config.guess'
configure.ac:67: installing 'autostuff/config.sub'
configure.ac:44: installing 'autostuff/install-sh'
configure.ac:44: installing 'autostuff/missing'
Makefile.am: installing './INSTALL'
Makefile.am: installing 'autostuff/depcomp'
parallel-tests: installing 'autostuff/test-driver'
autoreconf: Leaving directory `.'

$ ./configure --prefix=/lib/x86_64-linux-gnu

checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking whether make supports nested variables... yes
checking whether make supports nested variables... (cached) yes
checking whether make supports the include directive... yes (GNU style)
checking for gcc... gcc
checking whether the C compiler works... yes
....

$ make

make all-am
 CC serialport.lo
 CC timing.lo
 CC linux.lo
 CC linux_termios.lo
 CCLD libserialport.la

$ sudo make install
 /usr/bin/mkdir -p '/lib/x86_64-linux-gnu/lib'
 /bin/bash ./libtool --silent --mode=install /usr/bin/install -c libserialport.la '/lib/x86_64-linux-gnu/lib'
 /usr/bin/mkdir -p '/lib/x86_64-linux-gnu/include'
 /usr/bin/install -c -m 644 libserialport.h '/lib/x86_64-linux-gnu/include'
 /usr/bin/mkdir -p '/lib/x86_64-linux-gnu/lib/pkgconfig'
 /usr/bin/install -c -m 644 libserialport.pc '/lib/x86_64-linux-gnu/lib/pkgconfig'

But nothing changes from my side, may be I miss sth?

Now I can see the device port (ACM0) in the dropped menu of IIO-Oscilloscope.

but I can not find my device with context description: Could not get IIO context: permission denied 

I also tried to build no-OS project with with IIO support (https://wiki.analog.com/resources/tools-software/no-os-software/iio)

make clean_all

make TINYIIOD=y

but I has this error: 

/home/hp/zed/no-OS_2019_r2/projects/ad9361/build/app/noos/libraries/iio/iio_types.h:48:10: fatal error: tinyiiod.h: No such file or directory
#include "tinyiiod.h"
^~~~~~~~~~~~
compilation terminated.
make[1]: *** [../../tools/scripts/generic.mk:305: /home/hp/zed/no-OS_2019_r2/projects/ad9361/build/objs/ad9361/build/app/noos/iio/iio_ad9361/iio_ad9361.o] Error 1
make: *** [../../tools/scripts/generic.mk:280: all] Error 2



Sorry, I forgot this at no-OS/
git submodule update --init --recursive
The probleme has been solved, I can do make TINYIIOD=y without any problem

I still has the problem on the connection via serial port

ERROR: sp_blocking_read_next has timedout
ERROR: READ LINE: -110

I used HDL and no-OS 2019_R2
IIO-Oscilloscope and libiio version 2021_R2

I have seen in a question that travisfcollins mentioned that we just only used iio-oscilloscope with the ma ster branch of no-OS?
Any one can help? 

I have the same problem and i should notice that running oscilloscope from root will help: "sudo osc". Setting variable LIBSERIALPORT_DEBUG shows that problem is with serialport. 

Sorry, but I did it with sudo osc.

The problem has been solved by changing the baud rate into 115200 in parameter.h (#define UART_BAUDRATE 115200). After recompiling, running the project, and connecting to the server with the serial port set to 115200 as usual, the issue was successfully addressed."