[Gta04-owner] Kernel 3.7 GPS antenna power issue

Dr. H. Nikolaus Schaller hns at goldelico.com
Mon Jun 10 10:16:00 CEST 2013


There is another issue [1] with GPS in the 3.7 kernel.
The VSIM voltage is not 2.8 V but 1.8 V.

root at gta04:/sys/class/regulator/regulator.10# cat name
VSIM
root at gta04:/sys/class/regulator/regulator.10# cat microvolts 
1800000
root at gta04:/sys/class/regulator/regulator.10# cat state status
enabled
normal
root at gta04:/sys/class/regulator/regulator.10# rfkill block gps
root at gta04:/sys/class/regulator/regulator.10# cat state status
disabled
off
root at gta04:/sys/class/regulator/regulator.10# cat microvolts 
1800000
root at gta04:/sys/class/regulator/regulator.10# 

It can be controlled by rfkill (using a voltmeter shows that
it is 0.00 V in disabled state). But I see only 1.79 V in the
enabled state. This is not enough to power the antenna
signal amplifier so we loose 10-20 dB in signal strength.

The min/max settings are ok:

root at gta04:/sys/class/regulator/regulator.10# cat min_microvolts max_microvolts 
2800000
2800000
root at gta04:/sys/class/regulator/regulator.10# 

I have checked that with two different boards.

Who has an idea what is going on here?

Nikolaus

[1]: http://projects.goldelico.com/p/gta04-kernel/issues/439/


More information about the Gta04-owner mailing list