[Out-Of-Topic]How to Access Input GPIO of OMAP4460 without L4Re (direct access)

Martin Schröder martin.schroeder at openlimit.com
Tue Jan 27 17:13:28 CET 2015

Am 27.01.2015 um 16:19 schrieb Erry Pradana Darajati:
> Hi L4 Hackers,
> My subject seems out of topic, but i don't know where i can ask this kind of thing, and i think there are many people have a
> knowledge about this subject.
> I have a problem. I want to directly access GPIO140 (in GPIO5 ball) as input.
> I have a function to print the value of GPIO5_DATAIN (0x4805 B138). But when i print that out, the value of it still not changed
> (zero value). I Conclude, the pin still not accepting the input. I have already done these things :
> 1. Set GPIO5_OE to 0x1
> 2. See the value of MCSPI1_CS3 Pad Configuration (0x4A10 013C) and it give me value like this (0x011B 001B) which is for GPIO_140 ->
> MUX_MODE=gpio_140. PULLUDENABLE=0x1(enable). PULLTYPESELECT=0x1(enable).
> Which is in my current knowledge, is a right setting for accepting input. But still, it's still not successful
> So where or what did i miss ? is it still any configuration / address to set ?
> I appologize for the Out-of-Topic Subject .Thank you for any answer and suggestion and help.

I would suggest as a first step doing this from U-Boot to get familar with the GPIOs. The commands are mw.l for writing and mr.l for 
reading. If this works then you can continue with your application and L4.


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