The i.MX6 CPU has one USB 2.0 OTG port with integrated PHY and three USB 2.0 Host ports.

USB interfaces on the ConnectCore 6

On the ConnectCore 6 system-on-module:

  • The USB OTG controller is available for peripheral use.

  • One USB Host controller is available for peripheral use.

On the ConnectCore 6 SBC:

  • USB_OTG is available at the micro AB-type connector on the bottom side of the board.

  • USB_H1 is connected to a four-port USB hub that makes it available at:

    • both ports of the stackable dual USB A-type connector on the top side of the board.

    • the PCIe connector.

    • the XBee socket (also available on an expansion connector).

Kernel configuration

You can manage the USB 2.0 support through the kernel configuration options:

  • Support for Host-side USB (CONFIG_USB)

  • EHCI HCD (USB 2.0) support (CONFIG_USB_EHCI_HCD)

  • ChipIdea Highspeed Dual Role Controller (CONFIG_USB_CHIPIDEA)

  • ChipIdea device controller (CONFIG_USB_CHIPIDEA_UDC)

  • ChipIdea host controller (CONFIG_USB_CHIPIDEA_HOST)

  • Freescale MXS USB PHY support (CONFIG_USB_MXS_PHY)

  • OTG support (CONFIG_USB_OTG)

All of these kernel configuration options are enabled as built-in on the default ConnectCore 6 SBC kernel configuration file.

The USB device driver provides the functionality for the USB gadget drivers. The USB gadget drivers implement one or more "functions", each providing a different capability.

The following gadget drivers are supported and enabled as loadable modules on the default ConnectCore 6 SBC kernel configuration file.

  • Mass Storage Gadget (CONFIG_USB_MASS_STORAGE)

  • Ethernet Gadget with CDC Ethernet support (CONFIG_USB_ETH)

  • Serial Gadget with ACM and CDC OBEX support (CONFIG_USB_G_SERIAL)

Gadget drivers are enabled as loadable modules because only one gadget function can be used at a time. Before using a gadget driver, you must first make sure no other gadget driver is loaded.

Kernel driver

The i.MX6 universal serial bus (USB) driver implements a standard Linux driver interface to the CHIPIDEA USB-HS On-The-Go (OTG) controller. The CHIPIDEA USB controller is enhanced host controller interface (EHCI) compliant.

The i.MX6 USB drivers are located at drivers/usb/.

File Description

chipidea/core.c

Chipidea IP core driver

chipidea/udc.c

Chipidea peripheral driver

chipidea/host.c

Chipidea host driver

chipidea/ci_hdrc_imx.c

i.MX glue layer

chipidea/otg.c

Chipidea OTG driver

chipidea/otg_fsm.c

Chipidea OTG HNP and SRP driver

chipidea/usbmisc_imx.c

i.MX SoC abstract layer

phy/phy-mxs-usb.c

i.MX USB physical driver

Device tree bindings and customization

The i.MX6 USB controller device tree bindings are documented at Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt.

Example: USB Host on the ConnectCore 6 SBC

USB_H1 port is configured by default to work as host. This is selected via the dr_mode property on the device tree:

i.MX6 device tree
usbh1: usb@02184200 {
	compatible = "fsl,imx6q-usb", "fsl,imx27-usb";
	reg = <0x02184200 0x200>;
	interrupts = <0 40 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&clks IMX6QDL_CLK_USBOH3>;
	fsl,usbphy = <&usbphy2>;
	fsl,usbmisc = <&usbmisc 1>;
	dr_mode = "host";
	ahb-burst-config = <0x0>;
	tx-burst-size-dword = <0x10>;
	rx-burst-size-dword = <0x10>;
	status = "disabled";
};
ConnectCore 6 SBC device tree
&usbh1 {
	fsl,reset-gpio = <&gpio3 10 GPIO_ACTIVE_HIGH>;
	status = "okay";
};

Example: USB OTG on the ConnectCore 6 SBC

USB_OTG port is configured by default to work as otg. This is selected via the dr_mode property on the device tree, which defaults to otg if not defined.

i.MX6 device tree
usbotg: usb@02184000 {
	compatible = "fsl,imx6q-usb", "fsl,imx27-usb";
	reg = <0x02184000 0x200>;
	interrupts = <0 43 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&clks IMX6QDL_CLK_USBOH3>;
	fsl,usbphy = <&usbphy1>;
	fsl,usbmisc = <&usbmisc 0>;
	ahb-burst-config = <0x0>;
	tx-burst-size-dword = <0x10>;
	rx-burst-size-dword = <0x10>;
	fsl,anatop = <&anatop>;
	status = "disabled";
};
ConnectCore 6 SBC device tree
&usbotg {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_usbotg>;
	digi,power-line-active-high;
	status = "okay";
};


&iomuxc {
	usbotg {
		pinctrl_usbotg: usbotg {
			fsl,pins = <
				MX6QDL_PAD_GPIO_1__USB_OTG_ID 0x17059
				MX6QDL_PAD_EIM_D22__USB_OTG_PWR 0x17059
				MX6QDL_PAD_EIM_D21__USB_OTG_OC 0x17059
			>;
		};
	};
};

Using the USB port

See the following topics for information on how to use the USB port.