[Tinkerphones] ***UNCHECKED*** RE: Some questions about GTA04 and Neo900

H. Nikolaus Schaller hns at goldelico.com
Tue Jul 26 09:04:09 CEST 2016


Hi,

> Am 26.07.2016 um 05:23 schrieb roy jackson <roy.r.jackson at outlook.com>:
> 
> 
> Hi,
> 
>> As long as you find source code that works on a BeagleBoard (XM)
>> it appears to be a not that difficult task to adjust and add drivers for
>> peripherals not supported by the BeagleBoard (mainly display, touch,
>> i2c based sensors, audio). But if you have to port a kernel to the
>> processor first, it is a real challenge...
> 
> Not really ... 
> 
> * https://wiki.freebsd.org/BeagleBoard
> 
> btw
> 
> * http://blog.khubla.com/freebsd/building-a-beaglebone-freebsd-kernel

Ah, nice!

> 
> The "hard thing" is the display, but ncurses(3) suits well for my 
> "purposes" in context of present developement activities. 
> 
> Sooner or later, I'll start experimenting with the frame buffer
> in cotext of virtual terminal device vt(4) ... :)
> 
> * https://www.freebsd.org/cgi/man.cgi?query=vt&sektion=4&manpath=FreeBSD+10.3-RELEASE+and+Ports

For the display there is only some hardware dependent initialization of the display controller
so that it sends a memory region (frame buffer) to the panel.

We do that within U-Boot as well, so it might be as simple as copying that code:

http://git.goldelico.com/?p=gta04-uboot.git;a=blob;f=board/goldelico/gta04/dssfb.c;h=4eff169aa9b985f2606ac5b251c624691ac78b5f;hb=ab10e116463b384b21b2b96ff1173f2a0014a817

> 
>> The list of sensors of the GTA04 is included in the manual:
>> http://projects.goldelico.com/p/gta04-main/page/Manual/
>> 
>> There will be an update for the GTA04A5 board (some
>> sensors and i2c addresses have changed).
>> 
> 
> Fantastic! This is it what I've searched for. 
> 
> Thank you for the (hard) work compiling this
> outstanding manual!
> 
>>> 
>>> Are all integrated HW sensors deployed with same kind 
>>> of controlling MC?
>>> 
>>> 
>>> Exists a listing about ioctl(2) primitives which are accepted
>>> by WH sensors controlling MC?
>> 
>> On Linux sensors are more and more controlled by the iio
>> framework which allows to either read them (inefficiently) as
>> text files through /sys (usually /sys/class/iio). Or by opening
>> a file that presents a stream of iio data records.
> 
> Ahhh... I've understood. The Interfaces against HW Sensors 
> areimplemented (top-half) as character devices (bottom-half)  
> throught "ioo" Kernel Progarmmers Interface (KPI)?

Yes.

> 
> I've planned to implement an interface against HW sensors by 
> utilizing OpenBSD HW Sensors Framework (is ported to FreeBSD) 
> for this purpose.
> 
> * https://www.openbsd.org/papers/asiabsdcon2009-sensors-paper.pdf

From a first look though it (I have no OpenBSD experience) it looks
roughly equivalent to the Linux iio approach. Details are of course
very different.

> 
>> Hope that this helps a little, even if it is less than 50% answered :)
> 
> Thank you! This helps me a lot in multiple ways! :)
> 
> How I can order the GTA04A5 board (for developement purposes)?

Here: http://shop.goldelico.com/wiki.php?page=GTA04

BR,
Nikolaus




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