Re: RTL28XX driver

Antti Palosaari <crope@xxxxxx> · Wed, 18 Apr 2012 21:35:33 +0300

The method should be selected based of knowledge if GPIO used for 

controlling FC0012 tuner OR controlling some other part (LNA, anatenna 

switch, etc.) So you have to identify meaning first. Look inside FC0012 

driver to see if there is some mention about that GPIO.

UNLESS we cannot identify meaning of GPIO, fe_ioctl_overrid must be used 

(inside rtl28xxu driver). All unknown "hacks" must reside DVB-USB-driver 

(in that case dvb_usb_rtl28xxu) leaving demodulator and tuner drivers clean.

regards
Antti

On 18.04.2012 21:20, Thomas Mair wrote:

I don't know what it really is either but the comments are the following.

if (frequency>  300000000)
{

	printk("  %s : Tuner :FC0012 V-band (GPIO6 high)\n", __FUNCTION__);		
}
else
{
	printk("  %s : Tuner :FC0012 U-band (GPIO6 low)\n", __FUNCTION__);	
}

I looked into both mechanisms but can't really decide which one would
be the best one for this. What is the correct ioctl constant to listen
for or do I define an own constant? And how is the ioctl command
issued within the demod driver?

Thomas

2012/4/18 Antti Palosaari<crope@xxxxxx>:

On 18.04.2012 20:18, Thomas Mair wrote:

I have been working on the driver over the past days and been making
some progress. Right now I am stuck with a small problem that I have
no idea how to deal with.

It seems that the fc0012 tuner supports V-Band and U-Band. To switch
between those modes a GPIO output value needs to be changed. In the
original Realtek driver this is done at the beginning of the
set_parameters callback. Is there a different callback that can be
used for this or is it ok to write a RTL2832u register from the
demodulator code?

Aah, I suspect it is antenna switch or LNA GPIO. You don't say what is
meaning of that GPIO...
If it is FC0012 input, which I think it is not, then you should use FE
callback (named as callback too) with  DVB_FRONTEND_COMPONENT_TUNER param.
But I suspect it is not issue.

So lets introduce another solution. It is fe_ioctl_override. Use it.

You will find good examples both cases using following GIT greps
git grep fe_ioctl_override drivers/media
git grep FRONTEND_COMPONENT

Antti
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