[linux-dvb] CX22702 i2c gate

Andrew de Quincey adq_dvb at lidskialf.net
Fri Nov 25 23:19:57 CET 2005


On Friday 25 Nov 2005 21:59, Steve Toth wrote:
> 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?)

Previously I've exported another function - e.g. stv0299_enableplli2c() that 
PLL drivers can call.. but I'm not sure if this sort of solution would be any 
use..



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