add sysfs trigger

Hi,

Sorry, looks like the documentation is a bit outdated.

These days you don't need to register a sysfs trigger device anymore. When you enable the sysfs trigger in your config, you'll find a /sys/bus/iio/devices/iio_sysfs_trigger/ folder, which contains two files: "add_trigger" and "remove_trigger". You can create a new sysfs trigger by writing a id to the "add_trigger". E.g. `echo 0 > add_trigger`. This will create a new sysfs trigger, which you can access at "/sys/bus/iio/devices/iio:triggerX", where X is a the trigger number. Typically it will be 0 for the first trigger, 1 for the second, etc.

To remove a sysfs trigger again just write the same id you used when registering it to the "remove_trigger" file. E.g `echo 0 > remove_trigger`.

I'll update the documentation on the wiki.

- Lars

Update: Fix sysfs paths

Hi,

Yes, you can use the sysfs trigger for the AD7606. Please check the documentation for the AD7606 how to assign a trigger. But be aware, that the sysfs trigger is a oneshot trigger, writing to "trigger_now" will cause AD7606 to capture exactly one sample. If you want to do continuous sampling you can for example use the blackfin timer trigger.

- Lars

Thank you so mutch, Lars!

Can I use the sysfs trigger for AD7606 clock?

If I will add sysfs trigger, I need only specify the .convst pin for, or something else? How to organize interfacing of sysfs trigger and ADC?

Hi,

Just click on the link in the previous post, it will take you to the timer trigger documentation.

- Lars

Ok, that certainly is not to be expected. Did you enable the timer trigger in your kernel config?

To debug this further it would be good if you can send me the output of

`ls /sys/bus/platform/device` and `ls /sys/bus/platform/drivers`

Thanks,

- Lars

Thank you, Lars!

How I can add the timer trigger? Is it the same like add "sysfs trigger"? If it otherwise I need information for which files should be edit to add appropriate struct for add timer trigger.

but after add platform device initialization (I did as written in http://wiki.analog.com/software/linux/docs/iio/iio-trig-bfin-timer), I saw that folder /sys/bus/iio/devices/ is empty.

Thank you for reply, Lars!

`ls /sys/bus/platform/device` give me 'iio_bfin_tmr_trigger.0'

in the "/sys/bus/platform/drivers" I see this trigger also.

I tried to resolve this problem:

1) I added the printk function for debug to "probe" function of the trigger and ADC AD7887. I think this by this way I can able to see the start of driver in the kernel.

Now see the starting information from ADC, but I don't see the starting information from trigger.

2) I enabled the debug information from spi in the kernel and I see this string from ADC driver:

ad7887: probe of spi1.0 failed with error -22

  To date I'm in a deadlock((

Hi,

-22, is EINVAL, which means most likely that your platform data is not setup correctly. Did you setup all the platform data fields as described in the documentation? It is important that you set all unconnected GPIOs  to -1 and not to 0.

- Lars

Ok, thank you so much, but what about trigger for set the sample frequency?

`ls /sys/bus/platform/device` give me 'iio_bfin_tmr_trigger.0'

in the "/sys/bus/platform/drivers" I see this trigger also. But trigger is not respond to the simple request from user space, such as:

echo > 1000