Openmoko Bug #2177: andy-tracking/de473ca8: unable to powerdown GPS

[Openmoko Public Trac]

#2177: andy-tracking/de473ca8: unable to powerdown GPS
-----------------------------+----------------------------------------------
 Reporter:  lindi            |          Owner:  openmoko-kernel
     Type:  defect           |         Status:  new            
 Priority:  normal           |      Milestone:                 
Component:  System Software  |        Version:  unspecified    
 Severity:  normal           |       Keywords:                 
 Haspatch:  0                |      Blockedby:                 
Estimated:                   |    Patchreview:                 
 Blocking:                   |   Reproducible:  always         
-----------------------------+----------------------------------------------

Comment(by lindi):

 I added some printk's around the code and tried to make sense of
 this. Here are my observations. Please take them with a grain of salt
 since I'm not a kernel developer:

 neo1973_gps.power_was_on is initially set to 0 but
 pcf50633_regulator_is_enabled() seems to return 1. In this state even
 repeated calls to gps_pwron_set(0) won't disable the regulator since
 it thinks it has already been disabled.

 Userland workaround:
 {{{
 if [ `cat $sys_pm_gps/pwron` = 1 ]; then
     echo 1 | sudo tee $sys_pm_gps/pwron
 fi
 echo 0 | sudo tee $sys_pm_gps/pwron
 }}}

 Kernel fix: Don't rely on power_was_on at all but just query
 regulator_is_enabled() all the time? Initialize power_was_on with 1?
 Something else?

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2177#comment:2>
docs.openmoko.org <http://docs.openmoko.org/trac/>
openmoko trac