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Re: GPIO use


David Anders Mar 26, 2012 9:11 PM
Posted in group: pandaboard
samsounda,

please review the docs on compile linux kernel for pandaboard.

Dave


On Mar 26, 10:14 pm, samsounda...@gmail.com wrote:
> I am having the same problem. I changed the files as you mentioned but what
> do I do from here? How do I get the file compiled and installed?
>
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> On Wednesday, March 14, 2012 2:14:40 PM UTC-5, qua...@gmail.com wrote:
>
> > *Mux probably means "Pins Multiplexing"*
>
> > see:* *http://elinux.org/BeagleBoardPinMux
>
> > Details of OMAP35x PinMux can be found in OMAP35x Applications Processor
> > TRM <http://www.ti.com/lit/ug/spruf98u/spruf98u.pdf> (spruf98u.pdf) in
> > section *7.4.4.3 Pad Multiplexing Register Fields* (page 782)
>
> > I created initalization part for GPIO. When I tried to show GPIO status
> > via "cat /sys/kernel/debug/gpio" I saw this:
>
> > GPIOs 32-63, gpio:
>
> > gpio-32 (pandaboard_exp_menu ) in hi
>
> > gpio-33 (pandaboard_exp_volup) in hi
>
> > gpio-36 (pandaboard_exp_power) in hi
>
> > gpio-37 (pandaboard_exp_voldw) in lo
>
> > gpio-38 (pandaboard_exp_back ) in lo
>
> > I was not able to control gpio-37 and gpio-38 (low state).
>
> > If you have some similar problem with addressing of GPIO you must add some
> > snipped to board-omap4panda.c file.*
> > *
>
> >  find (board-omap4panda.c):
>
> > #ifdef CONFIG_OMAP_MUX
>
> > static struct omap_board_mux board_mux[] __initdata = {
>
> >  and append code like this:
>
> >  * */** GPIO Expansion board */
>
> > // AD12 - GPIO 36 - HOME
>
> > OMAP4_MUX(GPMC_AD12, OMAP_PIN_INPUT | OMAP_MUX_MODE3),
>
> > // AD08 - GPIO 32 - MENU
>
> > OMAP4_MUX(GPMC_AD8, OMAP_PIN_INPUT | OMAP_MUX_MODE3),
>
> > // AD14 - GPIO 38 - BACK
>
> > OMAP4_MUX(GPMC_AD14, OMAP_PIN_INPUT | OMAP_MUX_MODE3),
>
> > // AD09 - GPIO 33 - VOLUME_UP
>
> > OMAP4_MUX(GPMC_AD9, OMAP_PIN_INPUT | OMAP_MUX_MODE3),
>
> > // AD13 - GPIO 37 - VOLUME_DOWN
>
> > OMAP4_MUX(GPMC_AD13, OMAP_PIN_INPUT | OMAP_MUX_MODE3),
>
> > Note: This snipped is from my configuration for chipsee expansion board.