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

[Daniel Baluta <daniel.baluta@intel.com>]

On Sun, Apr 26, 2015 at 10:30 PM, Jonathan Cameron <jic23@kernel.org> wrote:
> 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.

Yes, this is a good idea.
>
> 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
>>
>
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