Sterling-LWB5+ WiFi 5 + Bluetooth 5.2 Module

There are certain patch ranges within kernels 4.4 and 4.9 that need a modification so backports can build, the reason why we cannot fix it in backports is that we cannot track and differentiate between patch versions of the same 'major.minor' version of kernel. To fix this issue, move the function kobject_has_children from linux/kobject.h to drivers/base/core.c in your kernel source, rebuild the kernel and then rebuild backports.

Simply log into GitHub, go to the corresponding release packages page and click the "Watch" button (eye icon) in the top right of the page. Some radios (such as the LWB Series) requires you to download firmware separately from the product page; this firmware is updated on the product page in conjunction with GitHub releases.

Release Packages

It is best practice to include the source in your build system. If using Yocto, our external layer will do this for you.
Here is an example manually compiling using our SOM60 as a target in a Buildroot environment:

1. Download and extract the Sterling supplicant source.
2. Navigate to the "laird" directory.
3. Edit the config_laird file:
4. Find the following line, uncomment and change the path to your "openssl/include" directory:
   original line:
   #CFLAGS += -I/usr/local/openssl/include
   modified line:
   CFLAGS += -I/wb/buildroot/output/som60sd/build/host-libopenssl-1.1.1d/include
5. Run make with the following flags
   set:
CC="" for your cross-compile binary
PKG_CONFIG="" for your pkg-config binary
PKG_CONFIG_PATH="" for your pkgconfig directory
OBJCOPY="" for your objcopy binary

Note the following example is a single line command:
make CC="/wb/buildroot/output/som60sd/host/bin/arm-buildroot-linux-gnueabihf-gcc" PKG_CONFIG="/wb/buildroot/output/som60sd/host/bin/pkg-config" OBJCOPY="/wb/buildroot/output/som60sd/host/arm-buildroot-linux-gnueabihf/bin/objcopy" PKG_CONFIG_PATH="/wb/buildroot/output/som60sd/host/arm-buildroot-linux-gnueabihf/sysroot/usr/lib/pkgconfig"

In BlueZ, some commands such as l2test or l2ping are able to generate traffic on L2CAP layer. To test performance and reliability, you can use the l2test command:

On the server, run the command:

l2test -I 2000 -r

On the client side, run the command:

l2test -O 2000 -s XX:XX:XX:XX:XX:XX

If the binary returns "not found" or does not work after confirming the executable bit is set with chmod +x <filename>, then you will need to create a symlink pointing to the system's interpreter. The file tool will show the expected interpreter and architecture of a binary, readelf is a lot more verbose and is used to discover the expected "sonames" of shared libraries. These utilities do not have to be used on the target system and is convenient to use on a common x86 Linux machine. These utilities can be installed on Ubuntu with sudo apt install binutils.

Example output from the file command:
sterling_supplicant-arm-7.0.0.139/usr/sbin$ file wpa_supplicant
wpa_supplicant: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.3, for GNU/Linux 3.0.0, stripped

Example output from the readelf command:
sterling_supplicant-arm-7.0.0.139/usr/sbin$ readelf -ld wpa_supplicant Elf file type is EXEC (Executable file)
Entry point 0xba28
There are 10 program headers, starting at offset 52 Program Headers:
...
<edited>
...
      [Requesting program interpreter: /lib/ld-linux.so.3]
...
<edited>
...
Dynamic section at offset 0x176ee8 contains 30 entries:
  Tag        Type                         Name/Value
 0x00000001 (NEEDED)                     Shared library: [librt.so.1]
 0x00000001 (NEEDED)                     Shared library: [libnl-3.so.200]
 0x00000001 (NEEDED)                     Shared library: [libnl-genl-3.so.200]
 0x00000001 (NEEDED)                     Shared library: [libdl.so.2]
 0x00000001 (NEEDED)                     Shared library: [libdbus-1.so.3]
 0x00000001 (NEEDED)                     Shared library: [libgcc_s.so.1]
 0x00000001 (NEEDED)                     Shared library: [libc.so.6]
...
<edited>
...

To use this binary, we will have to confirm this symlink exists or create a new symlink pointing to the interpreter on the target filesystem:
cd /lib/
ls -l ld-*
-rwxr-xr-x    1 root     root        158772 Dec  2  2019 /lib/ld-2.26.so
ln -sf ld-2.26.so ld-linux.so.3
ls -l ld-*
-rwxr-xr-x    1 root     root        158772 Dec  2  2019 /lib/ld-2.26.so
lrwxrwxrwx    1 root     root            10 Dec 21 18:55 /lib/ld-linux.so.3 -> ld-2.26.so

If the binary now reports that a library is not found when executed, repeat the steps shown above for creating a library symlink/soname pointing to it's real name. This may require you to use the find command to discover the location of the library. Example for libnl-genl-3:
find / -name 'libnl-genl-3*' -exec ls -l {} 2>/dev/null \;
-rwxr-xr-x    1 root     root         18524 Feb 14 23:42 /usr/lib/libnl-genl-3.so.200.26.0
cd /usr/lib/
ln -sf libnl-genl-3.so.200.26.0 libnl-genl-3.so.200
ls -l libnl-genl-3*
-rwxr-xr-x    1 root     root         18524 Feb 14 23:42 /usr/lib/libnl-genl-3.so.200.26.0
lrwxrwxrwx    1 root     root            24 Feb 14 23:37 /usr/lib/libnl-genl-3.so.200 -> libnl-genl-3.so.200.26.0

If the library does not exist, you will have to include that package in your build. For instance if the above example libnl was missing, include the libnl package when building your filesystem.

If you don't want simultaneous ap/sta, you can run the commands:

nmcli conn add type wifi ifname wlan0 con-name softAP autoconnect no ssid softAP

nmcli conn modify softAP 802-11-wireless.mode ap 802-11-wireless.band bg 802-11d

nmcli conn up softAP

You can also do it via wpa_supplicant .conf files if you do not have nmcli.

In order to be able to leverage the Modular Approval of a wireless module the following requirements have to be met:

• The RF circuitry must be shielded
• The module must have buffered modulation/data inputs. Module must inherently ensure compliance under host fault (watch dog) conditions
• The module must have a regulated power supply
• An antenna needs to be attached permanently or a unique antenna connector must be mounted on the module
• The module must be compliant with the regulations in a stand-alone configuration
• The module must be labeled with its permanently affixed FCC ID label or use an electronic display
• A user manual needs to provide comprehensive instructions to explain compliance requirements.
• The module must comply with RF exposure requirements

To use an antenna that is not listed on your wireless modules datasheet, it must be of the same topology (e.g. dipole, PIFA, etc.), equal or lesser gain, and have the same in-band and out of band characteristics.

Note: Japan (MIC) lists applicable antennas on its certificates. If your antenna is not on the approved list, regardless of whether it is comparative, it must be added to the certificate before it can be used in Japan.

When the error "can't set line discipline" occurs when the patchram tool is used to bring up the Bluetooth HCI-UART device it is very likely that the "Bluetooth HCI UART" driver (or module) is not enabled in the Linux kernel configuration as module.