| Message ID | 1441144769-29211-14-git-send-email-crope@iki.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/01/2015 11:59 PM, Antti Palosaari wrote: > Add SDR specific notes to G_MODULATOR / S_MODULATOR documentation. > > Signed-off-by: Antti Palosaari <crope@iki.fi> > --- > Documentation/DocBook/media/v4l/vidioc-g-modulator.xml | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml > index 80167fc..affb694 100644 > --- a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml > +++ b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml > @@ -78,6 +78,15 @@ different audio modulation if the request cannot be satisfied. However > this is a write-only ioctl, it does not return the actual audio > modulation selected.</para> > > + <para><link linkend="sdr">SDR</link> specific modulator types are > +<constant>V4L2_TUNER_SDR</constant> and <constant>V4L2_TUNER_RF</constant>. > +Valid fields for these modulator types are <structfield>index</structfield>, > +<structfield>name</structfield>, <structfield>capability</structfield>, > +<structfield>rangelow</structfield>, <structfield>rangehigh</structfield> > +and <structfield>type</structfield>. All the rest fields must be s/rest/remaining/ > +initialized to zero by both application and driver. I would drop this sentence. The spec is clear about which fields have to be set by the user. The only thing I would mention here is that txsubchans should be initialized to 0 by applications (we might want to use it in the future) when calling S_MODULATOR. For S_TUNER it is the same: only mention that audmode should be initialized to 0 for these SDR tuner types. > +Term modulator means SDR transmitter on this context.</para> s/Term/The term/ s/on/in/ Note: the same typos are in patch 12/13. Perhaps this sentence should be rewritten since it is not clear what you mean. I guess the idea is that 'modulator' is not a good match to what actually happens in the SDR hardware? How about: "Note that the term 'modulator' is a misnomer for type V4L2_TUNER_SDR since this really is a DAC and the 'modulator' frequency is in reality the sampling frequency of the DAC." I hope I got that right. And do something similar for patch 12/13. > + > <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl > is available.</para> > > Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/04/2015 01:26 PM, Hans Verkuil wrote: > On 09/01/2015 11:59 PM, Antti Palosaari wrote: >> Add SDR specific notes to G_MODULATOR / S_MODULATOR documentation. >> >> Signed-off-by: Antti Palosaari <crope@iki.fi> >> --- >> Documentation/DocBook/media/v4l/vidioc-g-modulator.xml | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml >> index 80167fc..affb694 100644 >> --- a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml >> +++ b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml >> @@ -78,6 +78,15 @@ different audio modulation if the request cannot be satisfied. However >> this is a write-only ioctl, it does not return the actual audio >> modulation selected.</para> >> >> + <para><link linkend="sdr">SDR</link> specific modulator types are >> +<constant>V4L2_TUNER_SDR</constant> and <constant>V4L2_TUNER_RF</constant>. >> +Valid fields for these modulator types are <structfield>index</structfield>, >> +<structfield>name</structfield>, <structfield>capability</structfield>, >> +<structfield>rangelow</structfield>, <structfield>rangehigh</structfield> >> +and <structfield>type</structfield>. All the rest fields must be > > s/rest/remaining/ > >> +initialized to zero by both application and driver. > > I would drop this sentence. The spec is clear about which fields have to be set > by the user. The only thing I would mention here is that txsubchans should be > initialized to 0 by applications (we might want to use it in the future) when > calling S_MODULATOR. > > For S_TUNER it is the same: only mention that audmode should be initialized to > 0 for these SDR tuner types. > >> +Term modulator means SDR transmitter on this context.</para> > > s/Term/The term/ > s/on/in/ > > Note: the same typos are in patch 12/13. > > Perhaps this sentence should be rewritten since it is not clear what you > mean. I guess the idea is that 'modulator' is not a good match to what actually > happens in the SDR hardware? > > How about: > > "Note that the term 'modulator' is a misnomer for type V4L2_TUNER_SDR since > this really is a DAC and the 'modulator' frequency is in reality the sampling > frequency of the DAC." > > I hope I got that right. > > And do something similar for patch 12/13. I added it mainly because struct v4l2_modulator is somehow misleading as it contains both modulator and RF frontend specific stuff and especially misleading for SDR case as modulator is located in a host computer software. On DVB side modulator/demodulator and tuner are split more correctly. If you look that struct v4l2_modulator: index: common field name: common field capability: contains both RF frontend and modulator stuff rangelow: RF frontend specific rangehigh: RF frontend specific txsubchans: modulator specific type: common field reserved: reserved So actually most field on that struct v4l2_modulator are RF frontend specific, not modulator. Same applies to struct v4l2_tuner. These should be probably: tuner => receiver modulator => transmitter Or even better, like DVB side, split modulator/demodulator and RF stuff to own structs. But as it is not reasonable to start changing those, so I decided to add comment for tuner that it means SDR receiver and for modulator it means SDR transmitter. regards Antti > >> + >> <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl >> is available.</para> >> >> > > Regards, > > Hans >
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml index 80167fc..affb694 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-modulator.xml @@ -78,6 +78,15 @@ different audio modulation if the request cannot be satisfied. However this is a write-only ioctl, it does not return the actual audio modulation selected.</para> + <para><link linkend="sdr">SDR</link> specific modulator types are +<constant>V4L2_TUNER_SDR</constant> and <constant>V4L2_TUNER_RF</constant>. +Valid fields for these modulator types are <structfield>index</structfield>, +<structfield>name</structfield>, <structfield>capability</structfield>, +<structfield>rangelow</structfield>, <structfield>rangehigh</structfield> +and <structfield>type</structfield>. All the rest fields must be +initialized to zero by both application and driver. +Term modulator means SDR transmitter on this context.</para> + <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl is available.</para>
Add SDR specific notes to G_MODULATOR / S_MODULATOR documentation. Signed-off-by: Antti Palosaari <crope@iki.fi> --- Documentation/DocBook/media/v4l/vidioc-g-modulator.xml | 9 +++++++++ 1 file changed, 9 insertions(+)