"/dev/mem" -- how to find GPIO mapping

Question

I am interested to know how we can find out at which address are my hardware registers mapped on "/dev/mem".

Suppose if someone am interested to control GPIO using mmap command.

http://elinux.org/RPi_Low-level_peripherals#GPIO_Driving_Example_.28C.29

This link tell the mapping directly, but does not tell how can we find at what address does mapping for hardware devices starts ?

Please suggest on this point.

Any reply will be appreciable.

Regards.

Have you looked into this question? – Sai Nov 24 '12 at 15:31 — Sai, Nov 24 '12 at 15:31
Here is another interesting question about it. – Jivings Nov 25 '12 at 08:29 — Jivings, Nov 25 '12 at 08:29

score 2 · Answer 1 · answered Nov 24 '12 at 22:36

2

The code you reference is using the following to address the GPIO controller.

// Access from ARM Running Linux

#define BCM2708_PERI_BASE        0x20000000
#define GPIO_BASE                (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */

The GPIO base address is 0x20200000

The code maps this address to an allocated piece of RAM (i.e. a buffer).

answered Nov 24 '12 at 22:36

Dan M

61
3

but data sheet says ;-- – apple Nov 25 '12 at 06:48

"/dev/mem" -- how to find GPIO mapping

1 Answers1