Karicheri, Muralidharan a écrit :
We need
streaming capability in the driver. This is how our driver works
with mt9t031 sensor
raw-bus (10 bit)
vpfe-capture ----------------- mt9t031 driver
| |
V V
VPFE MT9T031
VPFE hardware has internal timing and DMA controller to
copy data frame by frame from the sensor output to SDRAM.
The PCLK form the sensor is used to generate the internal
timing.
So, what is missing in the driver apart from the ability to specify
a frame-rate?
[MK] Does the mt9t031 output one frame (snapshot) like in a camera or can it output frame continuously along with PCLK, Hsync and Vsync signals like in a video streaming device. VPFE capture can accept frames continuously from the sensor synchronized to PCLK, HSYNC and VSYNC and output frames to application using QBUF/DQBUF. In our implementation, we have timing parameters for the sensor to do streaming at various resolutions and fps. So application calls S_STD to set these timings. I am not sure if this is an acceptable way of implementing it. Any comments?
PCLK, HSYNC, VSYNC are generated by the CMOS sensor. I don't think you
can set the timings. Depending on sensor settings, pixel clock speed etc
.., the frame rate will vary.
You could perhaps play with the CMOS sensor registers so that when
settings a standard, the driver somehow set the various exposition
parameter and pll settings to get a specified framerate.
This will vary with each sensor and each platform (because of
pixelclock). More over, chances are that it will be conflicting with
other control.
For example if you set a fixed gain and autoexpo, some sensor will see
a drop in fps under low light conditions. I think this kind of
arbitration should be left to userspace.
Unless the sensor supports a specific standard, I don't think the driver
should try to make behind the scene modification to camera sensor
register in response to a S_STD ioctl.
JP François
Thanks
Murali
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
_______________________________________________
Davinci-linux-open-source mailing list
Davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx
http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
--
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
