Ok, so after toying around a bit, I guess my above proposal is / would be a
bad example of how to use uio. In fact, I'm starting to think it is
"impossible" without hacking up a special driver, and changing a few
default files. It's pretty bad, when the light at the end of the tunnel,
seems to point to using uio_pruss . . . which actually makes a whole lot
more sense I suppose.






On Thu, Nov 19, 2015 at 7:57 PM, William Hermans <[email protected]> wrote:

> *You can override them thru userspace:*
>>
>> * usr0: for example:*
>>
>> * debian@test-bbb-3:/sys/class/**leds/beaglebone:green:usr0$ cat trigger*
>> * none nand-disk usb-gadget usb-host mmc0 mmc1 timer oneshot [heartbeat]*
>> * backlight gpio cpu0 default-on*
>> * debian@test-bbb-3:/sys/class/**leds/beaglebone:green:usr0$ cat
>> brightness*
>> * 0*
>> * debian@test-bbb-3:/sys/class/**leds/beaglebone:green:usr0$ cat
>> brightness*
>> * 255*
>>
>> * Change trigger to 'none' and just switch the brightness from 0 <-> 255*
>> * for on/off*
>>
>
> Ok that I knew of, just was not sure if that was the proper way to do
> things. I also read an old Dr. Dobbs article where you can echo "gpio_leds"
> to some unbind file in the debugfs file structure I think it was.
>
> Where I'm going with this though is that I want to setup a UIO "driver"
> using the USR LEDs as a simple UIO example for others to read. In fact, I'm
> still learning much of this myself but . . . heh
>
> On Thu, Nov 19, 2015 at 7:52 PM, Robert Nelson <[email protected]>
> wrote:
>
>> On Thu, Nov 19, 2015 at 8:47 PM, William Hermans <[email protected]>
>> wrote:
>> > Hello Robert,
>> >
>> > Thanks for the reply. Essentially, I've been looking through all of
>> that for
>> > the last week or so ( off an on ). I Kind of got stuck on stuff like
>> this:
>> >
>> > gpios = <&gpio1 21 GPIO_ACTIVE_HIGH>;
>> >
>> > Ok, so this whole line makes complete sense to me, except the variable
>> that
>> > is being assigned. I have not been able to find any information on this
>> yet.
>> > Somewhere there was a mention to the gpio.h header file, but that file
>> only
>> > has two defines that can not possibly tell me what the variable "gpios"
>> > *is*.
>> >
>> > My end goal however is just to use the USR LEDs, but I want explicit
>> control
>> > of the LEDs for my app, so Linux is not "confused". At the same time, I
>> was
>> > hoping to avoid changing stock files if at all possible.
>> >
>> > Is this possible, or will I have to modify the board files no matter
>> what ?
>>
>> You can override them thru userspace:
>>
>> usr0: for example:
>>
>> debian@test-bbb-3:/sys/class/leds/beaglebone:green:usr0$ cat trigger
>> none nand-disk usb-gadget usb-host mmc0 mmc1 timer oneshot [heartbeat]
>> backlight gpio cpu0 default-on
>> debian@test-bbb-3:/sys/class/leds/beaglebone:green:usr0$ cat brightness
>> 0
>> debian@test-bbb-3:/sys/class/leds/beaglebone:green:usr0$ cat brightness
>> 255
>>
>> Change trigger to 'none' and just switch the brightness from 0 <-> 255
>> for on/off
>>
>> Regards,
>>
>> --
>> Robert Nelson
>> https://rcn-ee.com/
>>
>> --
>> For more options, visit http://beagleboard.org/discuss
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>
>

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