Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756083AbbKROjF (ORCPT ); Wed, 18 Nov 2015 09:39:05 -0500 Received: from mail-wm0-f52.google.com ([74.125.82.52]:38208 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756038AbbKROjA (ORCPT ); Wed, 18 Nov 2015 09:39:00 -0500 From: Marc Titinger To: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net Cc: daniel.baluta@intel.com, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org Subject: [RFC 5/9] iio: Documentation: Add IIO configfs documentation Date: Wed, 18 Nov 2015 15:38:31 +0100 Message-Id: <1447857515-23935-6-git-send-email-mtitinger@baylibre.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1447857515-23935-1-git-send-email-mtitinger@baylibre.com> References: <1447857515-23935-1-git-send-email-mtitinger@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4544 Lines: 145 From: Daniel Baluta Signed-off-by: Daniel Baluta Acked-by: Crt Mori --- Documentation/ABI/testing/configfs-iio | 21 ++++++++ Documentation/iio/iio_configfs.txt | 93 ++++++++++++++++++++++++++++++++++ 2 files changed, 114 insertions(+) create mode 100644 Documentation/ABI/testing/configfs-iio create mode 100644 Documentation/iio/iio_configfs.txt diff --git a/Documentation/ABI/testing/configfs-iio b/Documentation/ABI/testing/configfs-iio new file mode 100644 index 0000000..2483756 --- /dev/null +++ b/Documentation/ABI/testing/configfs-iio @@ -0,0 +1,21 @@ +What: /config/iio +Date: October 2015 +KernelVersion: 4.4 +Contact: linux-iio@vger.kernel.org +Description: + This represents Industrial IO configuration entry point + directory. It contains sub-groups corresponding to IIO + objects. + +What: /config/iio/triggers +Date: October 2015 +KernelVersion: 4.4 +Description: + Industrial IO software triggers directory. + +What: /config/iio/triggers/hrtimers +Date: October 2015 +KernelVersion: 4.4 +Description: + High resolution timers directory. Creating a directory here + will result in creating a hrtimer trigger in the IIO subsystem. diff --git a/Documentation/iio/iio_configfs.txt b/Documentation/iio/iio_configfs.txt new file mode 100644 index 0000000..f0add35 --- /dev/null +++ b/Documentation/iio/iio_configfs.txt @@ -0,0 +1,93 @@ +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" group. It is +automagically accessible when the configfs is mounted and can be found +under /config/iio/triggers. + +IIO software triggers implementation offers support for creating multiple +trigger types. A new trigger type is usually implemented as a separate +kernel module following the interface in include/linux/iio/sw_trigger.h: + +/* + * drivers/iio/trigger/iio-trig-sample.c + * sample kernel module implementing a new trigger type + */ +#include + + +static struct iio_sw_trigger *iio_trig_sample_probe(const char *name) +{ + /* + * This allocates and registers an IIO trigger plus other + * trigger type specific initialization. + */ +} + +static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt) +{ + /* + * This undoes the actions in iio_trig_sample_probe + */ +} + +static const struct iio_sw_trigger_ops iio_trig_sample_ops = { + .probe = iio_trig_sample_probe, + .remove = iio_trig_sample_remove, +}; + +static struct iio_sw_trigger_type iio_trig_sample = { + .name = "trig-sample", + .owner = THIS_MODULE, + .ops = &iio_trig_sample_ops, +}; + +module_iio_sw_trigger_driver(iio_trig_sample); + +Each trigger type has its own directory under /config/iio/triggers. Loading +iio-trig-sample module will create 'trig-sample' trigger type directory +/config/iio/triggers/trig-sample. + +We support the following interrupt sources (trigger types): + * hrtimer, uses high resolution timers as interrupt source + +3.1 Hrtimer triggers creation and destruction + +Loading iio-trig-hrtimer module will register hrtimer trigger types allowing +users to create hrtimer triggers under /config/iio/triggers/hrtimer. + +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 doesn't have any configurable attribute from /config dir. +It does introduce the sampling_frequency attribute to trigger directory. -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/