• Henrique de Moraes Holschuh's avatar
    rfkill: add read-write rfkill switch support · 801e49af
    Henrique de Moraes Holschuh authored
    Currently, rfkill support for read/write rfkill switches is hacked through
    a round-trip over the input layer and rfkill-input to let a driver sync
    rfkill->state to hardware changes.
    
    This is buggy and sub-optimal.  It causes real problems.  It is best to
    think of the rfkill class as supporting only write-only switches at the
    moment.
    
    In order to implement the read/write functionality properly:
    
    Add a get_state() hook that is called by the class every time it needs to
    fetch the current state of the switch.  Add a call to this hook every time
    the *current* state of the radio plays a role in a decision.
    
    Also add a force_state() method that can be used to forcefully syncronize
    the class' idea of the current state of the switch.  This allows for a
    faster implementation of the read/write functionality, as a driver which
    get events on switch changes can avoid the need for a get_state() hook.
    
    If the get_state() hook is left as NULL, current behaviour is maintained,
    so this change is fully backwards compatible with the current rfkill
    drivers.
    
    For hardware that issues events when the rfkill state changes, leave
    get_state() NULL in the rfkill struct, set the initial state properly
    before registering with the rfkill class, and use the force_state() method
    in the driver to keep the rfkill interface up-to-date.
    
    get_state() can be called by the class from atomic context. It must not
    sleep.
    Signed-off-by: default avatarHenrique de Moraes Holschuh <hmh@hmh.eng.br>
    Acked-by: default avatarIvo van Doorn <IvDoorn@gmail.com>
    Cc: Dmitry Torokhov <dtor@mail.ru>
    Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
    801e49af
rfkill.c 12.2 KB