• Pantelis Koukousoulas's avatar
    V4L/DVB (5034): Pvrusb2: Enable radio mode round #1 · 275b2e28
    Pantelis Koukousoulas authored
    This is the logic that supports switching modes via e.g.,
      echo radio > /sys/class/pvrusb2/sn-*/ctl_input/cur_val.
    
    To do the mode switching we need to:
    a) broadcast AUDC_SET_RADIO and
    b) issue the CX2341X_ENC_MUTE_VIDEO command to the encoder. 
    
    The first is done by adding a new pvr2_i2c_op and having it trigger on 
    input change, the second by adding this command in pvr2_encoder_start() 
    and requesting an encoder restart on input change by setting 
    stale_subsys_mask appropriately. 
    
    The clues about AUDC_SET_RADIO and CX2341X_ENC_MUTE_VIDEO were kindly 
    provided by Hans Verkuil on the pvrusb2 mailing list. The idea to 
    implement mode switching this way (on input change) is due to Mike Isely.
    
    Why AUDC_SET_RADIO/VIDIOC_S_STD are used for switching? I can 't be sure, 
    but I think this can be traced to a cornell student being the first to 
    implement radio support in ivtv "as a different standard". I think the 
    rest just evolved from there (it 's in the ivtv ML archives).
    Signed-off-by: default avatarPantelis Koukousoulas <pakt223@freemail.gr>
    Signed-off-by: default avatarMike Isely <isely@pobox.com>
    Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
    275b2e28
pvrusb2-i2c-cmd-v4l2.h 1.58 KB