Forcing i.MX6 USB Host controller to Full-speed

[ganesank]

Is it possible to force i.MX6 host-controller to act like Full-speed host controller supporting only full-speed devices downstream in Linux? If so please share the details. We are facing ESD & EFT issues in our product which seems to reduce with full speed USB topology.

We are using Yocto 2.1 - Linux 4.1 with our custom board based on Advantech Q7 i.MX6D module.

[igorpadykov]

Hi Ganesan

please check

https://community.nxp.com/thread/343675 

Best regards
igor
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[ganesank]

Hi Igor,

The discussions are around limiting i.MX6 USB device controller (Chipidea) to Full-speed. I am looking for methods to limit speed of host controller usb_h1 to Full speed if it is possible.

Regards,

Ganesan. K

[dhvanil_patel1]

Hi Ganesan,

Have you found out to limit the USB bus speed to full speed?

Igor1z‌,

Can you please help us to limit the USB bus speed to full speed only on i.mx6ul linux

[ganesank]

Hi Patel,

If you are using 4.1.x kernel then it is very straightforward. For forcing host controller to full-speed just add one line  maximum-speed = "full-speed";  for the concerned host controller section in your device tree (.dts) file. For example, see my settings for host controller 1 (usbh1)

&usbh1 {
   vbus-supply = <&reg_usb_h1_vbus>;
   reset-gpios = <&gpio7 11 0>;
   maximum-speed = "full-speed";
   status = "okay";
};

This approach works for OTG as well.

[igorpadykov]

Hi Ganesan

solution is the same for host

Best regards
igor