drivers: iio: Adding channels to the simple_dummy module

Himanshu Jha himanshujha199640 at
Wed Jan 23 06:06:05 EST 2019

On Tue, Jan 22, 2019 at 11:33:18PM +0530, Bharath Vedartham wrote:
> Hey everyone,
> I am trying to get started with the IIO subsystem by doing the following tasks:
> In task 3, which requires us to add 3 channels to the dummy_device, I
> have added the structures in the dummy_channels array(which is of type
> struct chan_spec), similar to the other channels in the dummy_channels
> array.(in file drivers/iio/dummy/iio_simple_dummy.c)
> I also added elements to the enum iio_simple_dummy_scan_elements for the
> scan_index val.(in iio_simple_dummy.h)
> I recompiled the kernel and loaded the modules iio_dummy and
> iio_dummy_evgen using modprobe.
> is the right approach. I am not able to see any new channels being
> added to my /sys/bus/iio/devices/iio:device0/ directory?

Did you followed the configfs setup as illustrated in the aforementioned
link ?

Did the modules got loaded correctly ?

And if you're doing Task 3, I'd assume that the previous tasks were done
correctly ?

> printk is not printing to dmesg. I put printk in the probe function

Without any logs or diffs, it's hard to predict about where exactly
you're doing wrong.

Btw, we do have a IIO mailing list as well:
linux-iio at

Himanshu Jha
Undergraduate Student
Department of Electronics & Communication
Guru Tegh Bahadur Institute of Technology

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