V4L/DVB: stv090x: Add some notes about the internal tuner I/O control
authorManu Abraham <abraham.manu@gmail.com>
Sat, 13 Feb 2010 20:06:14 +0000 (17:06 -0300)
committerMauro Carvalho Chehab <mchehab@redhat.com>
Tue, 18 May 2010 03:46:51 +0000 (00:46 -0300)
Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
drivers/media/dvb/frontends/stv090x.c

index a461fdff2c9ca2d7ad9b95aa29d59ff6cec41f0c..425e7a43ae19ea8d3ecb8da3eb776d71304050f6 100644 (file)
@@ -758,6 +758,15 @@ static int stv090x_i2c_gate_ctrl(struct stv090x_state *state, int enable)
 {
        u32 reg;
 
+       /*
+        * NOTE! A lock is used as a FSM to control the state in which
+        * access is serialized between two tuners on the same demod.
+        * This has nothing to do with a lock to protect a critical section
+        * which may in some other cases be confused with protecting I/O
+        * access to the demodulator gate.
+        * In case of any error, the lock is unlocked and exit within the
+        * relevant operations themselves.
+        */
        if (enable)
                mutex_lock(&state->internal->tuner_lock);