Re: [PATCH 13/13] DocBook: add SDR specific info to G_MODULATOR / S_MODULATOR

2015-09-04 Thread Hans Verkuil 
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 
> ---
>  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.
>  
> +SDR specific modulator types are
> +V4L2_TUNER_SDR and V4L2_TUNER_RF.
> +Valid fields for these modulator types are index,
> +name, capability,
> +rangelow, rangehigh
> +and type. 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.

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.

> +
>  To change the radio frequency the  ioctl
>  is available.
>  
> 

Regards,

Hans
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Re: [PATCH 13/13] DocBook: add SDR specific info to G_MODULATOR / S_MODULATOR

2015-09-04 Thread Antti Palosaari 

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 
---
  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.

+SDR specific modulator types are
+V4L2_TUNER_SDR and V4L2_TUNER_RF.
+Valid fields for these modulator types are index,
+name, capability,
+rangelow, rangehigh
+and type. 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.


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




+
  To change the radio frequency the  ioctl
  is available.




Regards,

Hans



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[PATCH 13/13] DocBook: add SDR specific info to G_MODULATOR / S_MODULATOR

2015-09-01 Thread Antti Palosaari 
Add SDR specific notes to G_MODULATOR / S_MODULATOR documentation.

Signed-off-by: Antti Palosaari 
---
 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.
 
+SDR specific modulator types are
+V4L2_TUNER_SDR and V4L2_TUNER_RF.
+Valid fields for these modulator types are index,
+name, capability,
+rangelow, rangehigh
+and type. All the rest fields must be
+initialized to zero by both application and driver.
+Term modulator means SDR transmitter on this context.
+
 To change the radio frequency the  ioctl
 is available.
 
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