Hello, On Thu, 21 Mar 2013 09:54:46 +0100 CF Studelec <cfois...@studelec-sa.com> wrote:
> Hello, > > This is a simple board base on mpc5121e MCU. > > > Gpio is detected: kernel is compiled with its support - i got > gpiochip_find_base: found new base @224 in dmesg - on kernel 3.0.4. > > > But i'm unable to access it through /sys/class/gpio. I can successfully > export a pin (ie, if i type cat 224 > export, gpio224 is created), but i > can't successfully control it: > > > > echo "out" > /sys/class/gpio/gpio224/direction > > cat /sys/class/gpio/gpio224/value > > 0 > > echo 1 > /sys/class/gpio/gpio224/value > > cat /sys/class/gpio/gpio224/value > > 0 > > My need is a simple chipselect (well, 3 chipselect exactly ), for a > custom design. Running linux is mandatory. I suspect the MPC5121e to be > in the bad function mode, so: > > - does anyone knows how to change mode ? What register can i acces and > how ? does it worths a try ? For GPIO0 - GPIO7 pins you additionally need to configure the pin mux for GPIO mode, see IO_CONTROL_GP register description in the manual. > - does anyone successfully performed simple IO control ? We use it all the time, i.e. as SD-Card detect and/or write-protect GPIOs, as SPI Chips-Select GPIOs, etc. It works. > Last thing, i have tryed to access internal registers through /dev/mem, > but no success. There are very few ressources available for this > microcontroler, but i'm stick to it. Perhaps anybody knows how to access > (read) internal registers with /proc or sys-fs ? Accessing registers using /dev/mem should work (tested using devmem2.c tool with recent v3.9-rc4 kernel. Should work with older kernels too). Alternatively (as a quick test) you could configure the registers under U-Boot using "mw" command, assuming you are using U-Boot as a bootloader. HTH, Anatolij -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: off...@denx.de _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
