topic Re: I.Mx35 USB OTG Issue in i.MX Processors

I.Mx35 USB OTG Issue

SomAppu — Tue, 08 Nov 2011 08:49:57 GMT

hi,

I am using Freescale I.Mx35 PDK as the hardware and Linux kernel 2.6.31 as the OS.

I am facing some problem with the USB OTG.

USB OTG should work as both Host and also as a Device, depending upon the status of The UID pin, this is not happening.

What is working:-

1) When configured as Host, the OTG is working as a host and is also supplying the 5V power (for devices connected to it).

2) When Configured as Device, the OTG is working as a device and does not provide the 5V power.

3) UID Pin Status detection is working.

What is Not Working:-

1) When Configured as OTG Dual Role, it is not working as both Host and as a Device depending upon the status of the UID pin.

a. OTG is working as a USB Device, when the UID Pin is pulled high.

b. OTG is not working as a Host when the UID Pin is shorted to Ground.

2) When the UID Pin is pulled high, it detects it and mentions that it resumes its working as Device.

When the UID Pin is shorted to ground, it detects it and mentions that it is suspending its working as a Device, but it is not working as a Host and also not providing the power supply of 5V.

Re: I.Mx35 USB OTG Issue

PranavSanghadia — Fri, 10 Feb 2012 01:43:55 GMT

Hi Som,

I am having issues just to use USBOTG on imx35. I build linux kernel with USBOTG; but when I connect imx35 to my PC nothing happens.

Is there any hardware config required to enable USBOTG ?

Regards,

Pranav

Re: I.Mx35 USB OTG Issue

SomAppu — Fri, 10 Feb 2012 02:46:47 GMT

Hi Pranav,

You have to Configure the Linux Kernel to have the OTG Support.

You mentioned that nothing happens- What is not happening ?

Is it that -it is not working as a host or it is not working as a device?

Regards,

Som Appu

Re: I.Mx35 USB OTG Issue

PranavSanghadia — Fri, 10 Feb 2012 03:48:21 GMT

Hi Som,

I have connected imx35's USBOTG port to a Linux machine's USB port.But Linux machine does not detect, I also tried connecting it to Win 7 machine, but it also did not detect new hardware.

I followed the process given in Chapter 19 of Reference Manual to configure USBOTG. One of the option "IRAM for USB" generates compile time erros, so I did not select it. Am I referring to the right document?

Can you briefly described how did you compile your kernel and any other process to make USBOTG work? If possible can you share your .config?

Regards,

Pranav

Re: I.Mx35 USB OTG Issue

SomAppu — Fri, 10 Feb 2012 06:45:56 GMT

Hi Pranav,

I think you are trying to configure the OTG as a device - isn't it ?

if yes - did you make any USB Gadget selection selection ?

i am attaching the configuration what i used , go through it - it will work as a Device.

Re: I.Mx35 USB OTG Issue

PranavSanghadia — Fri, 10 Feb 2012 22:19:18 GMT

Hi Som,

Thanks a lot. It worked :-). I was able to configure OTG as device. After applying a patch I also connect a modem to IMX35 :-).

Regards,

Pranav