recursive locking problem

[Antti Palosaari <crope@iki.fi>]

I am working with AF9015 I2C-adapter lock. I need lock I2C-bus since 
there is two tuners having same I2C address on same bus, demod I2C gate 
is used to select correct tuner.

I am trapping demod .i2c_gate_ctrl() calls and locking bus according to 
that.

Is there any lock can do recursive locking but unlock frees all locks?

Like that:
gate_open
+gate_open
+gate_close
== lock is free

AFAIK mutex can do only simple lock() + unlock(). Semaphore can do 
recursive locking, like lock() + lock() + unlock() + unlock(). But how I 
can do lock() + lock() + unlock() == free.


Antti
-- 
http://palosaari.fi/