Hello, Currently the S_FMT IOCTL is used to configure the image resolution and (there by scaler settings) at the sensor (example MT9T031). Platforms like TI's DMxxx VPFE has Resizer in the pipeline that can be used as well by application to either zoom in a specific region of the capture image from the sensor or scale it up for some other reason. To do this we need to issue two S_FMT commands, 1st to set the capture frame resolution at the sensor and second to configure resize ration at the SOC Resizer. With the current API, I don't see a way this can be done. I wish we had some extra bytes in the S_FMT structure to add a flag that can indicate if S_FMT applies to the sensor or at the SOC (bridge). One way to implement this is to add a control to tell the bridge driver to send a specific IOCTL command to the sensor. Another use of such a command will be for control. For example if a specific control such as White balance is available at the SOC pipeline as well as at the sensor, then application can use the above control to direct that IOCTL command to the specific device.
You might argue that Media controller will allow you to direct such commands directly to the target device. This is true for control example I have mentioned above. But when applying S_FMT at the sensor, we might want to passing it through the bridge driver (as is the case with VPFE) so that it can request extra lines to be captured as overhead to allow processing the frame at the SOC pipeline in real time. So I do see this control command staying even after we have media controller. Let me know if you disagree with this proposal or have alternative to implement the same. If I don't hear anything against this approach, I would like to send patch to implement this control for vpfe capture driver. Murali Karicheri Software Design Engineer Texas Instruments Inc. Germantown, MD 20874 email: m-kariche...@ti.com -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html