[PATCH v2 22/29] docs: iio: convert to ReST

Mauro Carvalho Chehab
2019-06-18T20:55:33Z

Rename the iio documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
.../iio/{ep93xx_adc.txt => ep93xx_adc.rst} | 15 +++++-
.../{iio_configfs.txt => iio_configfs.rst} | 52 +++++++++++--------
Documentation/iio/index.rst | 12 +++++
drivers/iio/Kconfig | 2 +-
4 files changed, 56 insertions(+), 25 deletions(-)
rename Documentation/iio/{ep93xx_adc.txt => ep93xx_adc.rst} (71%)
rename Documentation/iio/{iio_configfs.txt => iio_configfs.rst} (73%)
create mode 100644 Documentation/iio/index.rst

diff --git a/Documentation/iio/ep93xx_adc.txt b/Documentation/iio/ep93xx_adc.rst
similarity index 71%
rename from Documentation/iio/ep93xx_adc.txt
rename to Documentation/iio/ep93xx_adc.rst
index 23053e7817bd..4fd8dea3f6b8 100644
--- a/Documentation/iio/ep93xx_adc.txt
+++ b/Documentation/iio/ep93xx_adc.rst
@@ -1,12 +1,16 @@
-Cirrus Logic EP93xx ADC driver.
+==============================
+Cirrus Logic EP93xx ADC driver
+==============================

1. Overview
+===========

The driver is intended to work on both low-end (EP9301, EP9302) devices with
5-channel ADC and high-end (EP9307, EP9312, EP9315) devices with 10-channel
touchscreen/ADC module.

2. Channel numbering
+====================

Numbering scheme for channels 0..4 is defined in EP9301 and EP9302 datasheets.
EP9307, EP9312 and EP9312 have 3 channels more (total 8), but the numbering is
@@ -17,13 +21,20 @@ Assuming ep93xx_adc is IIO device0, you'd find the following entries under

+-----------------+---------------+
| sysfs entry | ball/pin name |
- +-----------------+---------------+
+ +=================+===============+
| in_voltage0_raw | YM |
+ +-----------------+---------------+
| in_voltage1_raw | SXP |
+ +-----------------+---------------+
| in_voltage2_raw | SXM |
+ +-----------------+---------------+
| in_voltage3_raw | SYP |
+ +-----------------+---------------+
| in_voltage4_raw | SYM |
+ +-----------------+---------------+
| in_voltage5_raw | XP |
+ +-----------------+---------------+
| in_voltage6_raw | XM |
+ +-----------------+---------------+
| in_voltage7_raw | YP |
+-----------------+---------------+
diff --git a/Documentation/iio/iio_configfs.txt b/Documentation/iio/iio_configfs.rst
similarity index 73%
rename from Documentation/iio/iio_configfs.txt
rename to Documentation/iio/iio_configfs.rst
index 4e5f101837a8..ecbfdb3afef7 100644
--- a/Documentation/iio/iio_configfs.txt
+++ b/Documentation/iio/iio_configfs.rst
@@ -1,6 +1,9 @@
+===============================
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,
@@ -10,20 +13,22 @@ 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):
+Then, mount the configfs filesystem (usually under /config directory)::

-$ mkdir /config
-$ mount -t configfs none /config
+ $ 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
@@ -31,40 +36,40 @@ 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:
+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 <linux/iio/sw_trigger.h>
+ /*
+ * drivers/iio/trigger/iio-trig-sample.c
+ * sample kernel module implementing a new trigger type
+ */
+ #include <linux/iio/sw_trigger.h>

-static struct iio_sw_trigger *iio_trig_sample_probe(const char *name)
-{
+ 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)
-{
+ 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 = {
+ 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 = {
+ 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);

@@ -73,21 +78,24 @@ 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:
+e.g::

-$ mkdir /config/iio/triggers/hrtimer/instance1
-$ rmdir /config/iio/triggers/hrtimer/instance1
+ $ mkdir /config/iio/triggers/hrtimer/instance1
+ $ rmdir /config/iio/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.
diff --git a/Documentation/iio/index.rst b/Documentation/iio/index.rst
new file mode 100644
index 000000000000..0593dca89a94
--- /dev/null
+++ b/Documentation/iio/index.rst
@@ -0,0 +1,12 @@
+:orphan:
+
+==============
+Industrial I/O
+==============
+
+.. toctree::
+ :maxdepth: 1
+
+ iio_configfs
+
+ ep93xx_adc
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 1d736a4952ab..5bd51853b15e 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -28,7 +28,7 @@ config IIO_CONFIGFS
help
This allows configuring various IIO bits through configfs
(e.g. software triggers). For more info see
- Documentation/iio/iio_configfs.txt.
+ Documentation/iio/iio_configfs.rst.

config IIO_TRIGGER
bool "Enable triggered sampling support"
--
2.21.0