i'm actually looking for some information about how to access to particular GPIO pin from Linux User Space
Indeed i would like to read data from PC14 and PC2, and to send a clock signal to PC0 and PC1.
i've found on the internet an exemple of access to gpio using /dev/mem (http://www.lart.tudelft.nl/lartware/port/devmem2.c) but an adress (the virtual address of PCx) is needed to access to a pin.
i don't understand how i can found this adress in /dev/mem...does anyone know how it can be found?
or does anyone know a simple solution to read/write through the gpio?
i've looked in /proc/iomem but i haven't found interessant things
i'm using Linux 2.4.27 vrs1, in whom i've add gpio.c (that manage gpio interrupts) and my board is based on a rm9200, with 8MByte o flash memory and 32 MB of ram[root@EmbeddedLinux /proc]$more iomem
20000000-21ffffff : System RAM
2001b000-20175f27 : Kernel code
20175f28-201c2097 : Kernel data
fefc4000-fefc7fff : at91_serial
fefff200-fefff3ff : at91_serial
Frederic 'katolecho' Kwiatkowski