Linux/TMDSLCDK138: No GPIO access

Hello,

Do you have a link on where I can start?
Because I tried to recompile the meta-ti with Yocto/Openembedded, but for the MACHINE, omapl138 does not exist... And I don't know where to begin. Where do I have to do this ? "CONFIG_GPIO_SYSFS=y and CONFIG_SYSFS=y." I searched on the forum and TI website but found nothing interesting...

Thank you !

Hello,

Not sure about yocto, It should be in the linux source refer this link [1]

[1]

Cheers,

--Prabhakar Lad

Yocto is not mandatory to compile/rebuild the kernel.

Traditionally you use "git" to clone the source code from a git repository or download as a separate package and then use "make" build system to configur the build .


If you are using the evaluation kit most probably you are using pre-built binaries.
a1. Check if sysfs is mounted - "ls /sys/" if you find any directories under /sys that means sysfs is enabled and mounted.
a2. If not, then try doing "mount -t sysfs sysfs /sys"

a3. if it fails then check if sysfs is enabled by doing "zcat /proc/config.gz | grep CONFIG_SYSFS" you will see CONFIG_SYSFS=Y if it's enabled
a4. CHeck if GPIO_SYSFS is enabled by doing "zcat /proc/config.gz | grep CONFIG_GPIO_SYSFS"

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If either SYSFS is not enabled or GPIO_SYSFS is not enabled then you need to rebuild the kernel.
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Below link you'll find a video presentation on how to get the source code and re-build the kernel : Look for "OMAPL1 Linux Boot Up Procedure"
processors.wiki.ti.com/.../OMAPL1_PSP_WebEx_Presentations

when you do "make da850_omapl13x_*_defconfig* " as mentioned in the presentation it creates a default ".config" file which is used for the kernel build.
You need to modify this by doing "make menuconfig" and then press "/" to search and type "CONFIG_GPIO_SYSFS" it will list the location of the config option where you need to set teh value to "Y".
Do the same for "CONFIG_SYSFS" if not enabled.

Use the updated kernel image.

Regards,
RK

Thank you !

sysfs is enabled I have this :

root@omapl138-lcdk:~# ls /sys/
block     class     devices   fs        module
bus       dev       firmware  kernel    power
root@omapl138-lcdk:~# zcat /proc/config.gz |grep CONFIG_GPIO_SYSFS
# CONFIG_GPIO_SYSFS is not set
root@omapl138-lcdk:~# zcat /proc/config.gz | grep CONFIG_SYSFS
# CONFIG_SYSFS_DEPRECATED is not set
CONFIG_SYSFS=y

It seems I really don't have GPIOs enabled..

I have a look at your link and I let you know !