ppc405ex GPIO mapping

ppc405ex GPIO mapping

[Cote, Sylvain]

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Hi,

I am using kernel 2.6.25.20 on my Kilauea eval board (ppc405ex).  I want to access some GPIO's.  I have configured my u-boot to reflect what GPIO configuration I need.  I try to access my GPIO's in my driver.  When accessing GPIO's, I get this error in the kernel <<Unable to handle kernel paging request for data at address 0xef600800>>.   0xef600800 is the base address of GPIO in the ppc405ex.

It looks like GPIO's are not mapped in my kernel.  I have tried to add this entry in my dts file (under POB0: opb ) but it does not work:

GPIO: gpio@ef600800
{
compatible = "ibm,gpio-405ex";
reg = <ef600800 00000020>;
};


Any clues on this issues?


Thanks

Sylvain C.

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Re: ppc405ex GPIO mapping

[Lada Podivin]

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Hi,

I have the same board and I had a similar problem. I use 2.6.30, so I don't
know whether 2.6.25 supports the following - however, here's my suggestion.
Set these options in your kernel config: CONFIG_GPIOLIB=y and
CONFIG_PPC4xx_GPIO=y. Before compilation do "export
KCPPFLAGS=-DARCH_NR_GPIOS=32" - you have to let the kernel know, that your
GPIO has 32 pins (default value is 255) and compile the kernel.

Then change the line

compatible = "ibm,gpio-405ex";

to

compatible = "ibm,ppc4xx-gpio";

Ok! After this long journey you shoul be able to work with your GPIO pins
with functions like gpio_set_value() - from include/linux/gpio.h.
Documentation of these functions can be seen at
http://www.mjmwired.net/kernel/Documentation/gpio.txt

So, this is my solution. Maybe there are better ones, but this works well
for me :)

Best,
Lada Podivin

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Re: ppc405ex GPIO mapping

[Lada Podivin]

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Eh, sorry! I mean
include/asm-generic/gpio.h

NOT

include/linux/gpio.h

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