L4Re GPIO

Matthias Lange matthias.lange at kernkonzept.com
Mon Jan 5 09:45:42 CET 2015


On 12/30/2014 03:11 AM, Erry Pradana Darajati wrote:
>>Hi
>>This piece of code is missing the mapping of the GPIO4's MMIO region. For your >client program to successfully access the GPIO chip you need to create a virtual >device in IO's lua configuration file. Then you attach this device to a virtual bus. In the >startup script you hand IO's capability to that virtual bus to the 'vbus' cap of your >client. Then you client can query its vbus to discover connected devices and their >resources (see documentation of libvbus for reference). Then your client can map the >GPIO's chip MMIO region.
>>
>>Best,
>>Matthias.
> 
> Thank you for the explanation. I am reading through the libvbus doc
> right now. I'm still not fully understand but if i conclude the method
> to access the gpio of omap4460 in Pandaboard is : Define the
> res.mmio(address) in lua .dev script. Make vbus capabilities in .cfg.
> Make a program that can access GPIO via vbus with a client-server concept?
> I'm sorry i'm not fully understand about this, but what is the server of
> this client i am making.

You don't need a client server concept here. Your program can query its
vbus directly using the vbus API of libvbus.

> Also, before i your email, i already 'porting' a omap4460-chip driver in
> io module. and editing the .devs file so it matches with the memory of
> omap4460 (The two file is attached). Is my step right, and after that
> what should i do to be able to access it via my main program.
> When i try to compile the omap44x2.c it give me error like attached
> below. Is it because i'm not insert all of the virtual function in my
> program ? because actually i am not really in my goal in the mean time.

You need to implement pure virtual functions in your driver. That's why
the compiler errors out.

Best,
Matthias.

> 
> I really appreciate and say biggest thanks with any of your suggestion
> and answer
> 
> P.S : I am attaching my current main program just in case. And i still
> access it directly. without 
> 
> main2.c : http://pastebin.com/eZKqy1LE
> omap44x2.c : http://pastebin.com/0hupnnyR
> arm-omap4.devs : http://pastebin.com/pK6k7F5y
> error output :http://pastebin.com/s2skR3wu <http://pastebin.com/s2skR3wu>


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Matthias Lange, matthias.lange at kernkonzept.com, +49 - 351 - 41 88 86 14

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