Commit a544521e authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

V4L/DVB (3245): Added some comments about multiple tuner support. 




- Added some comments to make clearer how to use ioctl api to handle
multiple tuners at the same board.

Signed-off-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@brturbo.com.br>
parent 66e33dee

include/media/tuner.h

+19 −3
Original line number Diff line number Diff line
@@ -150,10 +150,26 @@ enum tuner_mode { 
	T_STANDBY	= 1 << 31

};



/* Older boards only had a single tuner device. Nowadays multiple tuner

   devices may be present on a single board. Using TUNER_SET_TYPE_ADDR

   to pass the tuner_setup structure it is possible to setup each tuner

   device in turn.



   Since multiple devices may be present it is no longer sufficient to

   send a command to a single i2c device. Instead you should broadcast

   the command to all i2c devices.



   By setting the mode_mask correctly you can select which commands are

   accepted by a specific tuner device. For example, set mode_mask to

   T_RADIO if the device is a radio-only tuner. That specific tuner will

   only accept commands when the tuner is in radio mode and ignore them

   when the tuner is set to TV mode.

 */



struct tuner_setup {

	unsigned short	addr;

	unsigned int	type;

	unsigned int	mode_mask;

	unsigned short	addr; 	/* I2C address */

	unsigned int	type;   /* Tuner type */

	unsigned int	mode_mask;  /* Allowed tuner modes */

};



struct tuner {