Re: Help needed in understanding v4l2_device_call_all

[Stefan Ringel <stefan.ringel@arcor.de>]

Am 23.04.2010 04:20, schrieb Bee Hock Goh:
> Mauro,
>
> Thanks.
>
> Previously, I have done some limited test and it seem that
> xc2028_signal seem to be getting the correct registered value for the
> detected a signal locked.
>
> Since I am now able to get video working(though somewhat limited since
> it still crashed if i change channel from mythtv), i will be spending
> more time to look getting a lock on the signal.
>
>
> Is line 139,140,155,156 needed? Its slowing down the loading of
> firmware and it working for me with the additional register setting.
>
>  138 if (addr == dev->tuner_addr << 1) {
> 139 tm6000_set_reg(dev, 0x32, 0,0);
> 140 tm6000_set_reg(dev, 0x33, 0,0);
>   
use tm6010
> 141 }
> 142 if (i2c_debug >= 2)
> 143 for (byte = 0; byte < msgs[i].len; byte++)
> 144 printk(" %02x", msgs[i].buf[byte]);
> 145 } else {
> 146 /* write bytes */
> 147 if (i2c_debug >= 2)
> 148 for (byte = 0; byte < msgs[i].len; byte++)
> 149 printk(" %02x", msgs[i].buf[byte]);
> 150 rc = tm6000_i2c_send_regs(dev, addr, msgs[i].buf[0],
> 151 msgs[i].buf + 1, msgs[i].len - 1);
> 152
> 153 if (addr == dev->tuner_addr << 1) {
> 154 tm6000_set_reg(dev, 0x32, 0,0);
> 155 tm6000_set_reg(dev, 0x33, 0,0);
>   
use tm6010
>
> On Fri, Apr 23, 2010 at 4:35 AM, Mauro Carvalho Chehab
> <mchehab@redhat.com> wrote:
>   
>> Bee Hock Goh wrote:
>>     
>>> Hi,
>>>
>>> I am trying to understand how the subdev function are triggered when I
>>> use v4l2_device_call_all(&dev->v4l2_dev, 0, tuner, g_tuner,t) on
>>> tm600-video.
>>>       
>> It calls tuner-core.c code, with g_tuner command. tuner-core
>> checks what's the used tuner and, in the case of tm6000, calls the corresponding
>> function at tuner-xc2028. This is implemented on tuner_g_tuner() function.
>>
>> The function basically does some sanity checks, and some common tuner code, but
>> the actual implementation is handled by some callbacks that the driver needs to
>> define (get_afc, get_status, is_stereo, has_signal). In general, drivers use
>> get_status for it:
>>                fe_tuner_ops->get_status(&t->fe, &tuner_status);
>>
>>
>> You will find a good example of how to implement such code at tuner-simple
>> simple_get_status() function.
>>
>> In the case of tuner-xc2028, we never found a way for it to properly report the
>> status of the tuner lock. That's why this function is not implemented on the driver.
>>
>>     
>>> How am i able to link the callback from the tuner_xc2028 function?
>>>       
>> The callback is used by tuner-xc2028 when it detects the need of changing the
>> firmware (or when the firmware is not loaded yet, or when you select a standard
>> that it is not supported by the current firmware).
>>
>> Basically, xc2028 driver will use the callback that was set previously via:
>>
>>        v4l2_device_call_all(&dev->v4l2_dev, 0, tuner, s_config, &xc2028_cfg);
>>
>>
>>     
>>> Please help me to understand or directly me to any documentation that
>>> I can read up?
>>>
>>> thanks,
>>>  Hock.
>>> --
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>>>       
>>
>> --
>>
>> Cheers,
>> Mauro
>>
>>     
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-- 
Stefan Ringel <stefan.ringel@arcor.de>