[Gta04-owner] Further 3.17 kernel development for GTA04

Dr. H. Nikolaus Schaller hns at goldelico.com
Mon Nov 3 07:00:42 CET 2014


Am 02.11.2014 um 10:51 schrieb NeilBrown <neilb at suse.de>:

> I've made some useful progress.
> Nearly all the things that I need regularly work.  So I can make phone calls
> (on the GTA04a4, not on the a3),

ah, did you solve the ALSA sound driver issues?

> use the wifi, charge the battery and
> monitor its status, and turn the GPS on/off using my new approach.  There is
> no-longer an ‘rfkill' for GPS - opening /dev/ttyO1 does all that is needed.

Hm. I am not happy that there is no rfkill. Well, someone commented that
GPS is not a transmitter, but Linux provides the rfkill gps switch (and we have
not introduced it). And, basically the antenna amplifier might transmit (if it runs
out of control) so it is safer in an airplane situation to be able to turn off the
LNA power explicitly. But keep gpsd and tangogps running. A user might
be just looking into local maps.

> I'm not entirely happy with this code yet but it is quite usable.
> Suspend seems to work reliably, but power usage is way too high - about
> 50mA.  There are hints in some patches in 3.18-rc, so USB might be to blame
> for some of that extra usage, so I'll probably be looking that that when I
> next get some time.
> My kernel doesn't currently "export" the various GPIOs that need to be
> manually poked.
> I have this code:
>  for l in 186,high 175,high 23,low 21,high
>  do
>     g=${l%,*}
>     echo $g > /sys/class/gpio/export
>     echo ${l#*,} > /sys/class/gpio/gpio$g/direction
>  done
> in an init.d script which sets some of these up.  GPIO186 is particularly
> needed for turning the GSM modem on.

What are these gpios good for? The modem should be controlled through
rfkill wwan. For this we have prepared a special driver in the gta04-kernel that
pulses the modem gpio in a similar way as for GPS (there is no UART we can
use to auto-control modem power).

> I've re-organised my tree as a set of topic branch, mostly based on
> v3.17, though the 'dts' branch with device-tree changes is based on
> git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap
>   tag omap-for-v3.17/dt-gta04
> which has some gta04 stuff that didn't quite make 3.17 - is in 3.18-rc1
> The branches are:
> 'dts', 'hdq', 'dss', 'pwm-old', 'input', 'hacks', 'wifi', 'extcon', 'itg',
> ‘tty-slave', 'audio', 'twl4030' and 'charger'

the hdq patch (there is a missing/wrong compatible entry in the driver) 
appears to be the last missing piece we have to make it working .

Does it work for you? I see it start up and read the bq27000 several times,
but ca. 4.5 seconds after kernel startup it stops. I suspect some IRQ
interference (maybe from a subsystem that you do not have).

> which can individually be merged into the goldelico tree as required.
> They can be found on git://neil.brown.name/gta04 or viewed at
>   http://git.neil.brown.name/?p=gta04.git;a=heads


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