rfkill: clarify meaning of rfkill states

rfkill really should have been named rfswitch.  As it is, one can get
confused whether RFKILL_STATE_ON means the KILL switch is on (and
therefore, the radio is being *blocked* from operating), or whether it
means the RADIO rf output is on.

Clearly state that RFKILL_STATE_ON means the radio is *unblocked* from
operating (i.e. there is no rf killing going on).

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Documentation/rfkill.txt

@@ -8,6 +8,13 @@ rfkill - RF switch subsystem support
 ===============================================================================
 1: Implementation details
 
+The rfkill switch subsystem exists to add a generic interface to circuitry that
+can enable or disable the RF output of a radio *transmitter* of any type.
+
+When a rfkill switch is in the RFKILL_STATE_ON, the radio transmitter is
+*enabled*.  When the rfkill switch is in the RFKILL_STATE_OFF, the radio
+transmitter is *disabled*.
+
 The rfkill switch subsystem offers support for keys often found on laptops
 to enable wireless devices like WiFi and Bluetooth.
 

include/linux/rfkill.h

@@ -44,16 +44,16 @@ enum rfkill_type {
 };
 
 enum rfkill_state {
-	RFKILL_STATE_OFF	= 0,
-	RFKILL_STATE_ON		= 1,
+	RFKILL_STATE_OFF	= 0,	/* Radio output blocked */
+	RFKILL_STATE_ON		= 1,	/* Radio output active */
 };
 
 /**
  * struct rfkill - rfkill control structure.
  * @name: Name of the switch.
  * @type: Radio type which the button controls, the value stored
  *	here should be a value from enum rfkill_type.
- * @state: State of the switch (on/off).
+ * @state: State of the switch, "ON" means radio can operate.
  * @user_claim_unsupported: Whether the hardware supports exclusive
  *	RF-kill control by userspace. Set this before registering.
  * @user_claim: Set when the switch is controlled exlusively by userspace.