WL1835MOD: Unable to set TX Power with iw utility

Austen San Nicolas

Part Number: WL1835MOD
Other Parts Discussed in Thread: WL1835

We are using a BeagleBone Black Wireless running kernel firmware 4.19.94-ti-r42. The specific Debian image is Buster IoT for BeagleBone -- Debian 10.3 2020-04-06 4GB SD IoT.

We are utilizing the ‘iw’ command-line utility to set the TX power of a wlan0 device. We believe this sets the TX power of the WL1835mod module that’s on the BeagleBone:

iw dev wlan0 set txpower fixed 1400

After running the command, we run “iwconfig wlan0”, and it looks like it correctly fixes the TX power to 14 dBm; however, if we measure the output with a spectrum analyzer, it still goes up to the default 20 dBm.

Questions:

Are the WL1835mod device drivers not supported?
There is no download for the WiLink8 driver on the webpage: WILINK8-WIFI-NLCP Driver or library | TI.com. Would you be able to provide a download link for this?
We noticed that the “wlconf” utility can be used to build a .ini file into a .bin for configuring the WL1835mod device; however, we do not have the /usr/sbin/wlconf directory on our BeagleBone. We have the /lib/firmware/ti-connectivity/wl18xx-conf.bin and other binaries, but the wlconf utility does not appear to be on the BeagleBone (ref. attached file). Is there a way to check what version of this utility we have? How do we go about installing this utility to set the TX power?

Thanks,

Austen

over 1 year ago

0 Sabeeh Khan1 over 1 year ago

TI__Mastermind 20180 points

Hi Austen,

I believe we have had issues with the iw series of commands. What is the purpose of controlling the TX power?

We typically don't recommend editing the INI file, but it is a more reliable method of editing the TX power.

0 Sabeeh Khan1 over 1 year ago

TI__Mastermind 20180 points

WL1835 is certainly supported. The NLCP driver is upstreamed with the linux kernel. However, for 4.19 linux kernel, we also supply additional patches and call these set of patches "R8.8" revision of the wilink driver. To get started with it, please read through and follow the steps in this guide:

https://www.ti.com/lit/ug/swru561a/swru561a.pdf

By following those steps, you will also retrieve wlconf tools.

0 Austen San Nicolas over 1 year ago in reply to Sabeeh Khan1

Prodigy 10 points

Hi Sabeeh,

Is there another utility/command besides iw or the wlconf tools for setting the TX power? We'd rather not edit the INI file if we don't have to. We simply want to limit the TX power.

Thanks for your timely response!

0 Sabeeh Khan1 over 1 year ago in reply to Austen San Nicolas

TI__Mastermind 20180 points

I believe you should also be able to use calibrator tool: https://www.ti.com/lit/ug/swru562/swru562.pdf

However, that will only be for testing purposes, not production or functional mode.

0 Austen San Nicolas over 1 year ago in reply to Sabeeh Khan1

Prodigy 10 points

Thanks Sabeeh.

Is there a Linux kernel available for BeagleBone that supports setting the TX power via iw commands?

0 Sabeeh Khan1 over 1 year ago in reply to Austen San Nicolas

TI__Mastermind 20180 points

The wl18xx driver only supports a set of commands, and developers are not expected to add commands in the future. So I would say whatever commands the driver supports today is what can be expected. I'm working on a way to provide you with exactly what those commands are, i'll update you here when I find out.

My initial guess is that if you do 'iw list' those are the features that can be set by iw.

0 Sabeeh Khan1 over 1 year ago in reply to Sabeeh Khan1

TI__Mastermind 20180 points

Hi, I wasn't able to find an exact list of commands, however I would point you to the source code for the wlcore and wl18xx driver in the kernel.

{KERNEL_DIR}/drivers/net/wireless/ti/

0 Austen San Nicolas over 1 year ago in reply to Sabeeh Khan1

Prodigy 10 points

Hi Sabeeh,

We have decided to do a hardware fix in order to introduce attenuation along the TX path. This appears to be sufficient for our testing, but we may revisit the wlcore and wl18xx driver approach in the near future.

Thanks again for all of the informative feedback you have provided us!

Austen

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WL1835MOD: Unable to set TX Power with iw utility