mx31moboard MT9T031 camera support
Hi Guennadi,
I am trying to follow your developments at porting soc-camera to v4l2-subdev. However, even if I understand quite correctly soc-camera, it is quite difficult for me to get all the subtleties in your work.
That's why I am asking you for a little help: when do you think would be the best timing for me to add the mt9t031 camera support for mx31moboard within your current process ?
I guess it should not be too difficult, I had done it before, and I can base myself on what you have done for pcm037:
http://download.open-technology.de/soc-camera/20090617/0025-pcm037-add-MT9T031-camera-support.patch
Now I have a second question. On our robot, we physically have two cameras (one looking to the front and one looking at a mirror) connected to the i.MX31 physical bus. We have one signal that allows us to control the multiplexer for the bus lines (video signals and I2C) through a GPIO. This now works with a single camera declared in software and choices to the multiplexer done when no image transfer is happening ( /dev/video is not open). What do you think should be the correct way of dealing with these two cameras with the current driver implementation (should I continue to declare only one camera in the software) ?
And do you think it could be possible to "hot-switch" from one camera to the other ? My colleagues ask about it, I tell them that from my point of view this seems not possible without changing the drivers, and even the drivers would have to be changed quite heavily and it is not trivial.
Best Regards
Val
Signature · 4 lines
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1 [email protected], Phone: +41216937827 http://people.epfl.ch/valentin.longchamp MEA3485, Station 9, CH-1015 Lausanne
Quoted 9 lines · Valentin Longchamp
Hi Guennadi,
I am trying to follow your developments at porting soc-camera to v4l2-subdev. However, even if I understand quite correctly soc-camera, it is quite difficult for me to get all the subtleties in your work.
That's why I am asking you for a little help: when do you think would be the best timing for me to add the mt9t031 camera support for mx31moboard within your current process ?
You can do this now, based either on the v4l tree, or wait for Linus to pull it - a pull request has been sent ba Mauro yesterday, looks like Linus hasn't pulled yet.
The way you add your platform is going to change, and the pull, that I'm referring to above makes it possible for both "old style" and "new style" board camera data to work. Of course, it would be best for you to implement the "new style" platform data. You can do this by either looking at my patches, which I've posted to the lists earlier, and which are also included in my patch stack, which I announced yesterday. Or you can wait a bit until I update my pcm037 patch (going to do this now) and post it to arm-kernel. I'll (try not to forget to) add you to cc, that should be quite easy to follow for you.
Quoted 3 lines
I guess it should not be too difficult, I had done it before, and I can base myself on what you have done for pcm037:
http://download.open-technology.de/soc-camera/20090617/0025-pcm037-add-MT9T031-camera-support.patch
Yes, use this or wait a bit for an updated version.
Quoted 10 lines
Now I have a second question. On our robot, we physically have two cameras (one looking to the front and one looking at a mirror) connected to the i.MX31 physical bus. We have one signal that allows us to control the multiplexer for the bus lines (video signals and I2C) through a GPIO. This now works with a single camera declared in software and choices to the multiplexer done when no image transfer is happening (
/dev/videois not open). What do you think should be the correct way of dealing with these two cameras with the current driver implementation (should I continue to declare only one camera in the software) ?
Quoted 4 lines
And do you think it could be possible to "hot-switch" from one camera to the other ? My colleagues ask about it, I tell them that from my point of view this seems not possible without changing the drivers, and even the drivers would have to be changed quite heavily and it is not trivial.
Do the cameras use different i2c addresses? If they use the same address I don't think you'd be able to register them simultaneously. If they do use different addresses, you can register both of them and use platform .power() callback to switch between them using your multiplexer. See arch/sh/boards/mach-migor/setup.c for an example. There was also a proposal to use switching input to select a data source, but this is currently unsupported by soc-camera.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
Quoted 14 lines · Guennadi Liakhovetski
Quoted 9 lines · Valentin Longchamp
Hi Guennadi,
I am trying to follow your developments at porting soc-camera to v4l2-subdev. However, even if I understand quite correctly soc-camera, it is quite difficult for me to get all the subtleties in your work.
That's why I am asking you for a little help: when do you think would be the best timing for me to add the mt9t031 camera support for mx31moboard within your current process ?
You can do this now, based either on the v4l tree, or wait for Linus to pull it - a pull request has been sent ba Mauro yesterday, looks like Linus hasn't pulled yet.
Quoted 7 lines
The way you add your platform is going to change, and the pull, that I'm referring to above makes it possible for both "old style" and "new style" board camera data to work. Of course, it would be best for you to implement the "new style" platform data. You can do this by either looking at my patches, which I've posted to the lists earlier, and which are also included in my patch stack, which I announced yesterday. Or you can wait a bit until I update my pcm037 patch (going to do this now) and post it to arm-kernel. I'll (try not to forget to) add you to cc, that should be quite easy to follow for you.
Quoted 3 lines
I guess it should not be too difficult, I had done it before, and I can base myself on what you have done for pcm037:
http://download.open-technology.de/soc-camera/20090617/0025-pcm037-add-MT9T031-camera-support.patchYes, use this or wait a bit for an updated version.
OK, thanks a lot. Since I am busy at other things at the moment, I am going to wait for you updated version and that things are stabilized a little bit with the 31-rc1. And I will use the "new style" platform data.
Quoted 11 lines
Quoted 11 lines
Now I have a second question. On our robot, we physically have two cameras (one looking to the front and one looking at a mirror) connected to the i.MX31 physical bus. We have one signal that allows us to control the multiplexer for the bus lines (video signals and I2C) through a GPIO. This now works with a single camera declared in software and choices to the multiplexer done when no image transfer is happening (
/dev/videois not open). What do you think should be the correct way of dealing with these two cameras with the current driver implementation (should I continue to declare only one camera in the software) ?
Quoted 7 lines
Quoted 4 lines
And do you think it could be possible to "hot-switch" from one camera to the other ? My colleagues ask about it, I tell them that from my point of view this seems not possible without changing the drivers, and even the drivers would have to be changed quite heavily and it is not trivial.
Do the cameras use different i2c addresses? If they use the same address I don't think you'd be able to register them simultaneously. If they do use different addresses, you can register both of them and use platform .power() callback to switch between them using your multiplexer. See
arch/sh/boards/mach-migor/setup.cfor an example. There was also a proposal to use switching input to select a data source, but this is currently unsupported by soc-camera.
The sensor chips both are mt9t031 so they have the same i2c address (I have looked at the datasheet, and I don't think this can be changed). So I cannot use them both at the same time.
Now you talk about the .power() callback, I could use it so that the multiplexer is managed by it, using a similar mechanism as in mach-migor. If this could allow me one different /dev/video nod for each camera (that of course cannot be used at the same time), it would simplify a lot of things for my users. I will give it a try (hoping that this also works at driver registering ... we will see).
Thanks for your answers.
Val
Signature · 4 lines
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1 [email protected], Phone: +41216937827 http://people.epfl.ch/valentin.longchamp MEA3485, Station 9, CH-1015 Lausanne
Quoted 3 lines · Valentin Longchamp
The sensor chips both are mt9t031 so they have the same i2c address (I have looked at the datasheet, and I don't think this can be changed). So I cannot use them both at the same time.
Right, but I think, there are some i2c ICs, that allow for address translations. Don't remember what they are called, some multiplexers or some such.
Quoted 6 lines
Now you talk about the .power() callback, I could use it so that the multiplexer is managed by it, using a similar mechanism as in mach-migor. If this could allow me one different
/dev/videonod for each camera (that of course cannot be used at the same time), it would simplify a lot of things for my users. I will give it a try (hoping that this also works at driver registering ... we will see).
Don't think it would work, at least not with the current stack. With the new stack video devices are registered at host-driver registration time, after i2c devices are registered. It wouldn't work with the old stack either.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
Hi,
I am already working on porting MT9T031 driver to sub device framework. I have communicated this to Guennadi, earlier. So please don't work on it. I am going to send a patch for review in a week.
Thanks.
Murali Karicheri
Software Design Engineer
Texas Instruments Inc.
Germantown, MD 20874
email: [email protected]
Quoted 88 lines
-----Original Message-----
From: [email protected] [mailto:linux-media- [email protected]] On Behalf Of Guennadi Liakhovetski
Sent: Thursday, June 18, 2009 5:20 AM
To: Valentin Longchamp
Cc: Linux Media Mailing List; Sascha Hauer
Subject: Re: mx31moboard MT9T031 camera supportQuoted 3 lines · Valentin Longchamp
Hi Guennadi,
I am trying to follow your developments at porting soc-camera to v4l2-
subdev.
Quoted 4 lines
However, even if I understand quite correctly soc-camera, it is quite difficult for me to get all the subtleties in your work.
That's why I am asking you for a little help: when do you think would be
the
Quoted 1 line
best timing for me to add the mt9t031 camera support for mx31moboard
within
Quoted 1 line
your current process ?
You can do this now, based either on the v4l tree, or wait for Linus to pull it - a pull request has been sent ba Mauro yesterday, looks like Linus hasn't pulled yet.
The way you add your platform is going to change, and the pull, that I'm referring to above makes it possible for both "old style" and "new style" board camera data to work. Of course, it would be best for you to implement the "new style" platform data. You can do this by either looking at my patches, which I've posted to the lists earlier, and which are also included in my patch stack, which I announced yesterday. Or you can wait a bit until I update my pcm037 patch (going to do this now) and post it to arm-kernel. I'll (try not to forget to) add you to cc, that should be quite easy to follow for you.
Quoted 1 line
I guess it should not be too difficult, I had done it before, and I can
base
Quoted 2 lines
myself on what you have done for pcm037:
http://download.open-technology.de/soc-camera/20090617/0025-pcm037-add-MT9T031-camera-support.patch
Yes, use this or wait a bit for an updated version.
Quoted 1 line
Now I have a second question. On our robot, we physically have two
cameras
Quoted 1 line
(one looking to the front and one looking at a mirror) connected to the
i.MX31
Quoted 1 line
physical bus. We have one signal that allows us to control the
multiplexer for
Quoted 1 line
the bus lines (video signals and I2C) through a GPIO. This now works with
a
Quoted 1 line
single camera declared in software and choices to the multiplexer done
when no
Quoted 2 lines
image transfer is happening (
/dev/videois not open). What do you think should be the correct way of dealing with these two cameras with thecurrent
Quoted 1 line
driver implementation (should I continue to declare only one camera in
the
Quoted 3 lines
software) ?
And do you think it could be possible to "hot-switch" from one camera to
the
Quoted 1 line
other ? My colleagues ask about it, I tell them that from my point of
view
Quoted 1 line
this seems not possible without changing the drivers, and even the
drivers
Quoted 1 line
would have to be changed quite heavily and it is not trivial.
Do the cameras use different i2c addresses? If they use the same address I don't think you'd be able to register them simultaneously. If they do use different addresses, you can register both of them and use platform .power() callback to switch between them using your multiplexer. See
arch/sh/boards/mach-migor/setup.cfor an example. There was also a proposal to use switching input to select a data source, but this is currently unsupported by soc-camera.Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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