[linux-dvb] CX22702 i2c gate

Steve Toth stoth at hauppauge.com
Fri Nov 25 22:59:06 CET 2005


Hi,

The cx22702 demod has an i2c gate which is opened and closed on demand 
to allow traffic to pass through to the pll. By default it's open. With 
the Nova-T-PCI this is fine, because all access to the PLL naturally 
happens via the demod driver. The cx22702 driver is the obvious place to 
unlock and lock the gate... it's a function of the part.

However, the breaks the upcoming HVR1100 driver (and will also break the 
next two drivers to come after the HVR1100).

The HVR1100 driver is a Hybrid Analog (V4L) and DVB-T animal. The same 
PLL is used in both cases. Analog works normally on a clean boot, but as 
soon a DVB is used, the gate is locked and subsequent V4L analog I2C 
activity fails with -REMOTEIO errors. As you'd expect, DVB continue to 
work happily.

For the time being I've removed the gate locking mechanism from the 
cx22702 driver. However, other than removing the gate/lock permanently, 
or manually via a parameter, does anyone have any suggestions?

Anyone know how the other demods do this? (Or if they have this feature?)

Steve





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