docs: iio: convert to ReST

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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/iio/ep93xx_adc.txt → Documentation/iio/ep93xx_adc.rst

-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            |
   +-----------------+---------------+

Documentation/iio/iio_configfs.txt → Documentation/iio/iio_configfs.rst

+===============================
 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.

Documentation/iio/index.rst

+:orphan:
+
+==============
+Industrial I/O
+==============
+
+.. toctree::
+   :maxdepth: 1
+
+   iio_configfs
+
+   ep93xx_adc

drivers/iio/Kconfig

@@ -27,7 +27,7 @@ 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"