VAR-SOM-AM43 GPIO

VAR-SOM-AM43 - GPIO

GPIO state

The current state of the systems' GPIOs can be obtained in user-mode, as shown in the following example:

$ cat /sys/kernel/debug/gpio

The above command on Variscite's VAR-DVK-AM43 will show the following:

root@varsomam43:~# cat /sys/kernel/debug/gpio
GPIOs 0-31, platform/44e07000.gpio, gpio:
 gpio-6   (cd                  ) in  lo IRQ

GPIOs 32-63, platform/4804c000.gpio, gpio:
 gpio-48  (kim                 ) out lo
 gpio-52  (vmmcwl_fixed        ) out lo

GPIOs 64-95, platform/481ac000.gpio, gpio:

GPIOs 96-127, platform/481ae000.gpio, gpio:

GPIOs 128-159, platform/48320000.gpio, gpio:
 gpio-136 (?                   ) out lo
 gpio-154 (?                   ) out lo
 gpio-157 (ft5x06_irq_gpio     ) in  hi IRQ

GPIOs 160-191, platform/48322000.gpio, gpio:
 gpio-164 (sw6                 ) in  hi IRQ
 gpio-165 (sw5                 ) in  hi IRQ
 gpio-166 (sw4                 ) in  hi IRQ
 gpio-167 (vtt_fixed           ) out hi

GPIOs 510-511, platform/50000000.gpmc, omap-gpmc:

Each GPIO is defined as in or out and the state is shown as lo or hi.
For example , SW4 the Menu Button:
When SW4 is pressed the state will be:

 gpio-166 (sw4                 ) in  lo IRQ

When SW4d is released the state will be:

 gpio-166 (sw4                 ) in  hi IRQ

Reference reading

http://processors.wiki.ti.com/index.php/Linux_PSP_GPIO_Driver_Guide