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authorManu Abraham <abraham.manu@gmail.com>2010-02-13 20:06:14 (GMT)
committerMauro Carvalho Chehab <mchehab@redhat.com>2010-05-18 03:46:51 (GMT)
commitc8382c8e3295a1c85975c1898410f4d103650e4a (patch)
treeadd5d11bc6bc59b5919c6280963a2060b28bc52c
parent5817ea0c83665dbc117cb7ca637202da0fb1abce (diff)
downloadlinux-fsl-qoriq-c8382c8e3295a1c85975c1898410f4d103650e4a.tar.xz
V4L/DVB: stv090x: Add some notes about the internal tuner I/O control
Signed-off-by: Manu Abraham <manu@linuxtv.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
-rw-r--r--drivers/media/dvb/frontends/stv090x.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/media/dvb/frontends/stv090x.c b/drivers/media/dvb/frontends/stv090x.c
index a461fdf..425e7a4 100644
--- a/drivers/media/dvb/frontends/stv090x.c
+++ b/drivers/media/dvb/frontends/stv090x.c
@@ -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);