Commit 317a8455 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet

rfkill.txt: standardize document format

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- mark titles;
- comment contents index;
- mark literal blocks;
- adjust identation.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 620b470b
===============================
rfkill - RF kill switch support
===============================
1. Introduction
2. Implementation details
3. Kernel API
4. Userspace support
.. contents::
:depth: 2
1. Introduction
Introduction
============
The rfkill subsystem provides a generic interface to disabling any radio
transmitter in the system. When a transmitter is blocked, it shall not
......@@ -21,17 +21,24 @@ aircraft.
The rfkill subsystem has a concept of "hard" and "soft" block, which
differ little in their meaning (block == transmitters off) but rather in
whether they can be changed or not:
- hard block: read-only radio block that cannot be overridden by software
- soft block: writable radio block (need not be readable) that is set by
the system software.
- hard block
read-only radio block that cannot be overridden by software
- soft block
writable radio block (need not be readable) that is set by
the system software.
The rfkill subsystem has two parameters, rfkill.default_state and
rfkill.master_switch_mode, which are documented in admin-guide/kernel-parameters.rst.
rfkill.master_switch_mode, which are documented in
admin-guide/kernel-parameters.rst.
2. Implementation details
Implementation details
======================
The rfkill subsystem is composed of three main components:
* the rfkill core,
* the deprecated rfkill-input module (an input layer handler, being
replaced by userspace policy code) and
......@@ -55,7 +62,8 @@ use the return value of rfkill_set_hw_state() unless the hardware actually
keeps track of soft and hard block separately.
3. Kernel API
Kernel API
==========
Drivers for radio transmitters normally implement an rfkill driver.
......@@ -69,7 +77,7 @@ For some platforms, it is possible that the hardware state changes during
suspend/hibernation, in which case it will be necessary to update the rfkill
core with the current state is at resume time.
To create an rfkill driver, driver's Kconfig needs to have
To create an rfkill driver, driver's Kconfig needs to have::
depends on RFKILL || !RFKILL
......@@ -87,7 +95,8 @@ RFKill provides per-switch LED triggers, which can be used to drive LEDs
according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
5. Userspace support
Userspace support
=================
The recommended userspace interface to use is /dev/rfkill, which is a misc
character device that allows userspace to obtain and set the state of rfkill
......@@ -112,11 +121,11 @@ rfkill core framework.
Additionally, each rfkill device is registered in sysfs and emits uevents.
rfkill devices issue uevents (with an action of "change"), with the following
environment variables set:
environment variables set::
RFKILL_NAME
RFKILL_STATE
RFKILL_TYPE
RFKILL_NAME
RFKILL_STATE
RFKILL_TYPE
The contents of these variables corresponds to the "name", "state" and
"type" sysfs files explained above.
......
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