Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx> --- 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 + +* add "sysfs" trigger type -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
