Hi,
I am porting a Linux 3.18.19 kernel on a board which features an i.MX6.
I would like to use it as a real USB OTG, ie as a device or as a host depending on the USB_OTG_ID pin: when low the interface act as a host, when high it acts as a device.
The hardware is OK, as the USB OTG is working as host or device with a Linux 3.0.35 kernel.
When I connect a USB stick to USB OTG, it is enumerated.
When I connect USB OTG to a host PC and "modprobe g_mass_storage", the USB OTG is enumerated by the host PC.
I also see on the a scope that the USB_OTG_ID pin is correctly driven.
With the 3.18.19 kernel, I cannot have both device and host working as expected, even if the USB_OTG_ID is correctly driven.
I can only have one feature working, depending on dr_mode value in the the device tree.
1) &usbotg {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usbotg>;
vbus-supply = <®_5p0v>;
disable-over-current;
dr_mode = "otg";
status = "okay";
};
=> USB OTG can enumerate a USB stick (host OK), but cannot be enumerated by a host PC (device NOK)
After connecting to a host PC, I see the following output in dmesg: ci_hdrc ci_hdrc.0: timeout waiting for 00000800 in 11
2)
&usbotg {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usbotg>;
vbus-supply = <®_5p0v>;
disable-over-current;
dr_mode = "peripheral";
status = "okay";
};
=> USB OTG is enumerated by the host PC (device OK), but it cannot enumerate a USB stick (host NOK)
This seems normal, as the USB OTG is described as a peripheral, so it cannot work as a host.
What am I missing to have USB OTG working as a real OTG in case 1) ?
Regards,
David
