tree d0ded0209d6a908fffa155509dab58f260ca5a0a
parent 851897a4adc42ad7b6327e4c64f599c07a6c5ebb
author Antti Palosaari <crope@iki.fi> 1390617866 -0300
committer Mauro Carvalho Chehab <m.chehab@samsung.com> 1394045216 -0300

[media] v4l: add RF tuner gain controls

Modern silicon RF tuners used nowadays has many controllable gain
stages on signal path. Usually, but not always, there is at least
3 gain stages. Also on some cases there could be multiple gain
stages within the ones specified here. However, I think that having
these three controllable gain stages offers enough fine-tuning for
real use cases.

1) LNA gain. That is first gain just after antenna input.
2) Mixer gain. It is located quite middle of the signal path, where
RF signal is down-converted to IF/BB.
3) IF gain. That is last gain in order to adjust output signal level
to optimal level for receiving party (usually demodulator ADC).

Each gain stage could be set rather often both manual or automatic
(AGC) mode. Due to that add separate controls for controlling
operation mode.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>