How to determine gta04 hardware revision?

[Dr. H. Nikolaus Schaller]

Hi,

Am 15.07.2013 um 11:17 schrieb Nikita V. Youshchenko:

>> If you want to see the revision for informational purposes:
>> 
>> dmesg | fgrep Revision
> 
> Relying on dmesg immediately makes software unreliable, since kernel log 
> buffer may overflow
> 
>> Since the A3 board also lacks a mechanism to on/off the UMTS modem you
>> can check for the presence of the GPIO that controls it:
>> 
>> ls -l /sys/class/gpio/gpio186
> 
> Relying on GPIO number does not look good as well - numbers tent to be 
> dynamic and change over time. Need to read something immutable (and kernel 
> should provide that).

Yes, you are absolutely right that neither method should be used by user
space code and that is why I recommend not using the methods proposed
except for informational purposes, e.g. if someone wants to find out the revision
for marketing purposes when selling the board.

But you are wrong that GPIOs "are dynamic and change over time". They are
well documented (see the GTA04 manual) and are changed only when absolutely
necessary.

And the presence of GPIO186 indicates a specific feature that some boards
lack.

The gta04 design team aims that nobody should have to care about the gta04 hw
revision (except for handling conflicting hw-changes by the kernel).

Therefore the kernel is not designed to provide the hw-revision at all and you need
such "tricks" to conclude the board revision indirectly...

-- hns