Documentation/driver-api/rfkill.rst

2 rfkill - RF kill switch support
12 The rfkill subsystem provides a generic interface for disabling any radio
21 The rfkill subsystem has a concept of "hard" and "soft" block, which
32 The rfkill subsystem has two parameters, rfkill.default_state and
33 rfkill.master_switch_mode, which are documented in
40 The rfkill subsystem is composed of three main components:
42  * the rfkill core,
43  * the deprecated rfkill-input module (an input layer handler, being
45  * the rfkill drivers.
47 The rfkill core provides API for kernel drivers to register their radio
52 The rfkill core code also notifies userspace of state changes, and provides
68 Drivers for radio transmitters normally implement an rfkill driver.
70 Platform drivers might implement input devices if the rfkill button is just
72 implement an rfkill driver instead. This also applies if the platform provides
76 suspend/hibernation, in which case it will be necessary to update the rfkill
79 To create an rfkill driver, driver's Kconfig needs to have::
81 	depends on RFKILL || !RFKILL
83 to ensure the driver cannot be built-in when rfkill is modular. The !RFKILL
84 case allows the driver to be built when rfkill is not configured, in which
85 case all rfkill API can still be used but will be provided by static inlines
89 rfkill drivers that control devices that can be hard-blocked unless they also
90 assign the poll_hw_block() callback (then the rfkill core will poll the
93 rfkill provides per-switch LED triggers, which can be used to drive LEDs
100 The recommended userspace interface to use is /dev/rfkill, which is a misc
101 character device that allows userspace to obtain and set the state of rfkill
104 linux/rfkill.h, with one ioctl that allows turning off the deprecated input
110 userspace is able to get a consistent snapshot of all rfkill devices in the
111 system. Also, it is possible to switch all rfkill drivers (or all drivers of
115 After an application opens /dev/rfkill, it can read the current state of all
118 rfkill core framework.
120 Additionally, each rfkill device is registered in sysfs and emits uevents.
122 rfkill devices issue uevents (with an action of "change"), with the following
132 For further details consult Documentation/ABI/stable/sysfs-class-rfkill.