On Sun, Jun 14, 2009 at 06:59:13PM +0200, ext Hans Verkuil wrote: > On Sunday 14 June 2009 18:23:41 Trent Piepho wrote: > > On Sun, 14 Jun 2009, Eduardo Valentin wrote: > > > >> +/* FM Modulator class control IDs */ > > > >> +#define V4L2_CID_FM_TX_CLASS_BASE (V4L2_CTRL_CLASS_FM_TX | 0x900) > > > >> +#define V4L2_CID_FM_TX_CLASS (V4L2_CTRL_CLASS_FM_TX | 1) > > > >> + > > > >> +#define V4L2_CID_RDS_ENABLED (V4L2_CID_FM_TX_CLASS_BASE + 1) > > > >> +#define V4L2_CID_RDS_PI (V4L2_CID_FM_TX_CLASS_BASE + 2) > > > >> +#define V4L2_CID_RDS_PTY (V4L2_CID_FM_TX_CLASS_BASE + 3) > > > >> +#define V4L2_CID_RDS_PS_NAME (V4L2_CID_FM_TX_CLASS_BASE + 4) > > > >> +#define V4L2_CID_RDS_RADIO_TEXT (V4L2_CID_FM_TX_CLASS_BASE + 5) > > > > > > > > I think these RDS controls should be renamed to V4L2_CID_RDS_TX_. This makes > > > > it clear that these controls relate to the RDS transmitter instead of a > > > > receiver. I would not be surprised to see similar controls appear for an RDS > > > > receiver in the future. > > > > So there should there be different controls to set the same thing, one set > > for tx and another for rx? > > Sure. Say some RDS decoder stores the PI in a register. I can imagine that > we add a V4L2_CID_RDS_RX_PI control for that. Whereas a V4L2_CID_RDS_TX_PI > control will return the PI sent out by the encoder. > > Currently no such controls exist (or are needed) for an RDS decoder, but I > wouldn't be surprised at all if we need them at some point in the future. > > > > > > >> +#define V4L2_CID_PREEMPHASIS (V4L2_CID_FM_TX_CLASS_BASE + 17) > > > >> +enum v4l2_fm_tx_preemphasis { > > > >> + V4L2_FM_TX_PREEMPHASIS_DISABLED = 0, > > > >> + V4L2_FM_TX_PREEMPHASIS_50_uS = 1, > > > >> + V4L2_FM_TX_PREEMPHASIS_75_uS = 2, > > > >> +}; > > > > > > > > I suggest renaming this to V4L2_CID_FM_TX_PREEMPHASIS. There is already a > > > > similar V4L2_CID_MPEG_EMPHASIS control and others might well appear in the > > > > future, so I think this name should be more specific to the FM_TX API. > > > > The cx88 driver could get support for setting the fm preemphasis via a > > control. I added support via a module option, but a control would be > > better. You're saying it shouldn't use this fm preemphasis control? > > Correct. This set the pre-emphasis when transmitting. For receiving you want > a separate control. Although the enum should be made generic. So FM_TX can be > removed from the enum. > > Why should we have one rx and one tx control for this? Because you can have > both receivers and transmitters in one device and you want independent control > of the two. Yes, agreed here. There is the possibility to have receiver and transmitter both in the same device. So, I think it is better to have separated controls. > > It is my believe that the other fm_tx controls are unambiguously transmitter > related, so I don't think they need a TX prefix. It doesn't hurt if someone > can double check that, though. hmm.. I see no problem removing the fmtx prefix of the preemphasis enum. But, if it is becoming a generic enum, better to check if its meaning is the same of existing emphasis enum for mpeg. > > Regards, > > Hans > > -- > Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Eduardo Valentin -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html