• Antti Palosaari's avatar
    [media] v4l: add RF tuner gain controls · 80807fad
    Antti Palosaari authored
    
    
    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: default avatarAntti Palosaari <crope@iki.fi>
    Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
    80807fad
v4l2-ctrls.c 87.1 KB