Re: [PATCH v4 4/4] iio: Documentation: Add IIO configfs documentation

[Jonathan Cameron <jic23@kernel.org>]

On 20/04/15 15:02, Daniel Baluta wrote:
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Probably need to start Documentation/ABI/testing/configfs-iio (or something like that)
as well to document the ABI elements fully.

This plain text doc is particularly useful to hopefully get feedback on the interface
from those who might not dive into the details of the series.  Thanks!
> ---
>  Documentation/iio/iio_configfs.txt | 67 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 67 insertions(+)
>  create mode 100644 Documentation/iio/iio_configfs.txt
> 
> diff --git a/Documentation/iio/iio_configfs.txt b/Documentation/iio/iio_configfs.txt
> new file mode 100644
> index 0000000..1aa66d1
> --- /dev/null
> +++ b/Documentation/iio/iio_configfs.txt
> @@ -0,0 +1,67 @@
> +Industrial IIO configfs support
> +
> +1. Overview
> +
> +Configfs is a filesystem-based manager of kernel objects. IIO uses some
> +objects that could be easily configured using configfs (e.g.: devices,
> +triggers).
> +
> +See Documentation/filesystems/configfs/configfs.txt for more information
> +about how configfs works.
> +
> +2. Usage
> +
> +In order to use configfs support in IIO we need to select it at compile
> +time via CONFIG_IIO_CONFIGFS config option.
> +
> +Then, mount the configfs filesystem (usually under /config directory):
> +
> +$ mkdir /config
> +$ mount -t configfs none /config
> +
> +At this point, all default IIO groups will be created and can be accessed
> +under /config/iio. Next chapters will describe available IIO configuration
> +objects.
> +
> +3. Software triggers
> +
> +One of the IIO default configfs groups is the "triggers" groups. It is
> +automagically accessible when the configfs is mounted and can be found
> +under /config/iio/triggers.
> +
> +Software triggers are created under /config/iio/triggers directory. A sofware
> +trigger name MUST be of the following form:
> +	* <trigger-type>-<trigger-name>:
> +Where:
> +	* <trigger-type>, specifies the interrupt source (e.g: hrtimer)
> +	* <trigger-name>, spefcifies the IIO device trigger name
> +
> +We support now to following interrupt sources (trigger types):
> +	* hrtimer, uses high resolution timers as interrupt source
> +
> +3.1 Software triggers creation and destruction
> +
> +As simply as:
> +
> +$ mkdir /config/triggers/<trigger-type>-<trigger-name>
> +$ rmdir /config/triggers/<trigger-type>-<trigger-name>
> +e.g:
> +
> +$ mkdir /config/triggers/hrtimer-instance1
> +$ rmdir /config/triggers/hrtimer-instance1
> +
> +Each trigger can have one or more attributes specific to the trigger type.
> +
> +3.2 "hrtimer" trigger types attributes
> +
> +"hrtimer" trigger type has only one attribute:
> +
> +$ ls /config/triggers/hrtimer-instance1
> +sampling_frequency
> +
> +sampling_frequency - represents the period in Hz between two consecutive
> +iio_trigger_poll calls. By default it is set to 100Hz.
> +
> +4. Further work
I wouldn't bother with this section here.  
> +
> +* add "sysfs" trigger type
>