i'm looking at the docs and tried the obvious but it didn't seem to
work. in order to recognize the version of beagleboard, i can see
what happens in the u-boot code:
/*
* Routine: get_board_revision
* Description: Detect if we are running on a Beagle revision Ax/Bx,
* C1/2/3, C4 or xM. This can be done by reading
* the level of GPIO173, GPIO172 and GPIO171. This should
* result in
* GPIO173, GPIO172, GPIO171: 1 1 1 => Ax/Bx
* GPIO173, GPIO172, GPIO171: 1 1 0 => C1/2/3
* GPIO173, GPIO172, GPIO171: 1 0 1 => C4
* GPIO173, GPIO172, GPIO171: 0 0 0 => xM
*/
int get_board_revision(void)
{
int revision;
if (!gpio_request(171, "") &&
!gpio_request(172, "") &&
!gpio_request(173, "")) {
gpio_direction_input(171);
gpio_direction_input(172);
gpio_direction_input(173);
revision = gpio_get_value(173) << 2 |
gpio_get_value(172) << 1 |
gpio_get_value(171);
} else {
printf("Error: unable to acquire board revision GPIOs\n");
revision = -1;
}
return revision;
}
however, in the latest kernel tree, it seems things have changed
slightly:
/*
* OMAP3 Beagle revision
* Run time detection of Beagle revision is done by reading GPIO.
* GPIO ID -
* AXBX = GPIO173, GPIO172, GPIO171: 1 1 1
* C1_3 = GPIO173, GPIO172, GPIO171: 1 1 0
* C4 = GPIO173, GPIO172, GPIO171: 1 0 1
* XMA/XMB = GPIO173, GPIO172, GPIO171: 0 0 0
* XMC = GPIO173, GPIO172, GPIO171: 0 1 0
*/
now that's useful since there are now allegedly different values for
xM A/B, and xM C, and i have a rev C.
so what exactly does one do to read those values? i tried:
barebox@Texas Instrument's Beagle:/ gpio_direction_input 171
barebox@Texas Instrument's Beagle:/ gpio_get_value 171
but what do i check? the shell variable $? i'm not sure what i
should do next.
rday
p.s. my plan is to port that code to barebox, of course. first, i
just want to see the values 0,1,0 from those gpio pins based on my
board version.
--
========================================================================
Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
========================================================================
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