Usb UVC webcam gadget bulk transfer

[alexandre_caron]

Hi, I'm developing a Linux camera and the output is uvc via the g_webcam gadget. For now I'm capable of 40fps with a resolution of 640x480 yuy2. I'm working with a imx7D

I'm capable of much higher fps on a cypress microcontroller but it uses bulk transfer.

It is possible to use bulk transfer with the imx? If yes how ? I need to achieve 60fps.

Thank you 

[igorpadykov]

Hi Alexandre

one can look at i.MX6ULL (the same usb as imx7D)  FreeRTOS  SDK examples:
../usb_examples/..usb_device_video_virtual_camera

available on Welcome | MCUXpresso SDK Builder

and nxp gstreamer plugins described in sect.7.3.10 Web camera Linux Guide

included in Linux 4.19.35_1.1.0 Documentation

Best regards
igor

[alexandre_caron]

I didn't find any sdk for the MX6ULL , only for the MX7ULP and it use the M4 core which i won't use in my design.

The section 7.3.10 refer to how to receive data from the usb camera, not how to act as a usb camera.

[igorpadykov]

sdk are available on link i.MX 6ULL Applications Processor | Single Arm® Cortex®-A7 @ 900 MHz | NXP 

SDK2.2_iMX6ULL_WIN

I am afraid there are no bulk transfer linux examples, in general nxp has special service

for helping with porting drivers: Commercial Support and Engineering Services | NXP 

Best regards
igor

[karangajjar]

Hi Alexandre Caron,

Please refer to Interrupt/Bulk Endpoint Operational Model in i.MX7D reference manual for details regarding bulk transfers.

You can also check the <kernel_src>/Documentation/usb/ehci.txt and <kernel_src>/include/linux/usb/gadget.h for more reference.

Regards,

Karan Gajjar