diff options
Diffstat (limited to 'Documentation/rfkill.txt')
| -rw-r--r-- | Documentation/rfkill.txt | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt index a289285d2412..7d3684e81df6 100644 --- a/Documentation/rfkill.txt +++ b/Documentation/rfkill.txt @@ -9,7 +9,7 @@ rfkill - RF kill switch support Introduction ============ -The rfkill subsystem provides a generic interface to disabling any radio +The rfkill subsystem provides a generic interface for disabling any radio transmitter in the system. When a transmitter is blocked, it shall not radiate any power. @@ -45,7 +45,7 @@ The rfkill subsystem is composed of three main components: * the rfkill drivers. The rfkill core provides API for kernel drivers to register their radio -transmitter with the kernel, methods for turning it on and off and, letting +transmitter with the kernel, methods for turning it on and off, and letting the system know about hardware-disabled states that may be implemented on the device. @@ -54,7 +54,7 @@ ways for userspace to query the current states. See the "Userspace support" section below. When the device is hard-blocked (either by a call to rfkill_set_hw_state() -or from query_hw_block) set_block() will be invoked for additional software +or from query_hw_block), set_block() will be invoked for additional software block, but drivers can ignore the method call since they can use the return value of the function rfkill_set_hw_state() to sync the software state instead of keeping track of calls to set_block(). In fact, drivers should @@ -65,7 +65,6 @@ keeps track of soft and hard block separately. Kernel API ========== - Drivers for radio transmitters normally implement an rfkill driver. Platform drivers might implement input devices if the rfkill button is just @@ -75,14 +74,14 @@ a way to turn on/off the transmitter(s). 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. +core with the current state at resume time. To create an rfkill driver, driver's Kconfig needs to have:: depends on RFKILL || !RFKILL to ensure the driver cannot be built-in when rfkill is modular. The !RFKILL -case allows the driver to be built when rfkill is not configured, which +case allows the driver to be built when rfkill is not configured, in which case all rfkill API can still be used but will be provided by static inlines which compile to almost nothing. @@ -91,7 +90,7 @@ rfkill drivers that control devices that can be hard-blocked unless they also assign the poll_hw_block() callback (then the rfkill core will poll the device). Don't do this unless you cannot get the event in any other way. -RFKill provides per-switch LED triggers, which can be used to drive LEDs +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). @@ -114,7 +113,7 @@ a specified type) into a state which also updates the default state for hotplugged devices. After an application opens /dev/rfkill, it can read the current state of all -devices. Changes can be either obtained by either polling the descriptor for +devices. Changes can be obtained by either polling the descriptor for hotplug or state change events or by listening for uevents emitted by the rfkill core framework. @@ -127,8 +126,7 @@ environment variables set:: RFKILL_STATE RFKILL_TYPE -The contents of these variables corresponds to the "name", "state" and +The content of these variables corresponds to the "name", "state" and "type" sysfs files explained above. - For further details consult Documentation/ABI/stable/sysfs-class-rfkill. |
