[Gta04-owner] 3.2-rc6-gta04 - another week, another rc.

[Dr. H. Nikolaus Schaller]

Hi Neil,

Am 19.12.2011 um 12:53 schrieb NeilBrown:

> On Mon, 19 Dec 2011 11:03:40 +0100 "Dr. H. Nikolaus Schaller"
> <hns at goldelico.com> wrote:
> 
>>> 
>>> I'll have to build myself a uboot ... are there any tricks I need to know, or
>> 
>> What do you intend to change?
> 
> Possibly nothing - just want to use the latest and want to know that I can
> build it myself.

If you have ideas or find issues, please report here:

http://projects.goldelico.com/p/gta04-uboot/issues/

U-Boot-bugs are usually easier and faster fixed than in the kernel.

> I have an idea that it might be good to drop 3V3 for a few milliseconds early
> in boot to make sure that the GPS is off so that when we toggle the
> on/off line we can be certain what state it is in.  That would best be done
> in uboot I think.

I am not sure if that is possible at all. The 3V3 line is coming from
a LDO that is a slave of the REGEN signal of the TPS65950. I.e.
it becomes enabled by hardware. And it can't be turned off because
there are other chips (e.g. the USB3322) which is not allowed to receive
1.8V signals on the inputs if there is no 3V3.

So I think we have no real chance to bring the GPS into a specific
state if it isn't there.

But - there should be a systematic pattern: after 3V3 is turned on,
it should be in reset state and need exactly one impulse.

If we really want to bring that into a kernel driver I would suggest
the following: if there is data on the serial port /dev/ttyO0 and no
user process has opened the file, we can assume that GPS is
on. We set a flag and just reset a timer of approx. 2 seconds. If
there is a timeout, we reset the flag assuming that we have to
switch on. I think this could be encapsulated in a W2SG driver.

But needs to modify omap-serial to send such a "I did receive data"
notification. This may make it difficult to get it upstream.

>>> is it just "./configure ; make" ??
>> 
>> Nothing special (except the branch name 'gta04e'). According to
>> 
>> http://projects.goldelico.com/p/gta04-uboot/page/Build/
>> 
>> make config_omap3_gta04
>> 
>> Please let me know if there are any problems.
> 
> $ make config_omap3_gta04
> make: *** No rule to make target `config_omap3_gta04'.  Stop.
> 
> (hunts around in Makefile)
> 
> $ make omap_gta04_config

Oops. You are right. I have a short shell script where the correct
make target is hard-coded.

I have updated the description page...

Many thanks!

> seems to work better.  "make" then creates a binary.  I'll test it when I get
> a chance.

If you get a u-boot.bin it should look good.

BR,
Nikolaus