[linux-dvb] Re: [Patch] Adding support for the Hauppage HVR1100

Johannes Stezenbach js at linuxtv.org
Tue Nov 29 20:25:50 CET 2005


Steve Toth wrote:
> Johannes Stezenbach wrote:
> >
> >In the DVB drivers, the PLL is not directly accessed by the
> >demod driver. It is done by the card driver.
> >
> >  
> The cx22702 driver currently issues the i2c_master commands to the pll, 
> nobody else does that (for DVB). Albeit, the pll address and some other 
> settings are driven by the card driver (in the cx88 code).

Sorry, should have been more clear: The DVB drivers
in drivers/dvb/ do the PLL access in the card driver,
not in the demod driver.

> >I.e. the cx88 driver knows from the PCI ids and eeprom
> >that the PLL is behind the cx22702 i2c gate. So it could
> >do the right thing.
> >
> >  
> Yes, that what the patch currently does - albeit the gate is left open 
> for HVR1100 products only.
> >But I assume the tuner.ko design makes this more difficult?
> >I don't have much knowledge about analog, but can the cx88
> >driver not hook the v4l ioctl and open the gate before
> >calling into tuner.ko?
> >
> >  
> Yes. More difficult. I can pollute tuner.ko with cx88 stuff, and have 
> the specific 'gate' flag passed in tuner_setup, or added to cx88_core, 
> but it didn't seem to make any sense when tuner.ko only knows about I2C 
> clients and tuner types (not demods and specific demod behavior, or even 
> DVB related things for that matter).

No, we shouldn't add cx88 specific stuff to tuner.ko, but in
cx88 where the VIDIOC_S_FREQUENCY ioctl is processed you should be able
to open the i2c gate before cx88_call_i2c_clients(), no?

Johannes



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