103 lines
3.3 KiB
Plaintext
103 lines
3.3 KiB
Plaintext
Generic USB Device Properties
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Usually, we only use device tree for hard wired USB device.
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The reference binding doc is from:
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http://www.devicetree.org/open-firmware/bindings/usb/usb-1_0.ps
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Four types of device-tree nodes are defined: "host-controller nodes"
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representing USB host controllers, "device nodes" representing USB devices,
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"interface nodes" representing USB interfaces and "combined nodes"
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representing simple USB devices.
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A combined node shall be used instead of a device node and an interface node
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for devices of class 0 or 9 (hub) with a single configuration and a single
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interface.
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A "hub node" is a combined node or an interface node that represents a USB
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hub.
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Required properties for device nodes:
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- compatible: "usbVID,PID", where VID is the vendor id and PID the product id.
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The textual representation of VID and PID shall be in lower case hexadecimal
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with leading zeroes suppressed. The other compatible strings from the above
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standard binding could also be used, but a device adhering to this binding
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may leave out all except for "usbVID,PID".
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- reg: the number of the USB hub port or the USB host-controller port to which
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this device is attached. The range is 1-255.
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Required properties for device nodes with interface nodes:
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- #address-cells: shall be 2
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- #size-cells: shall be 0
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Required properties for interface nodes:
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- compatible: "usbifVID,PID.configCN.IN", where VID is the vendor id, PID is
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the product id, CN is the configuration value and IN is the interface
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number. The textual representation of VID, PID, CN and IN shall be in lower
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case hexadecimal with leading zeroes suppressed. The other compatible
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strings from the above standard binding could also be used, but a device
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adhering to this binding may leave out all except for
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"usbifVID,PID.configCN.IN".
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- reg: the interface number and configuration value
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The configuration component is not included in the textual representation of
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an interface-node unit address for configuration 1.
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Required properties for combined nodes:
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- compatible: "usbVID,PID", where VID is the vendor id and PID the product id.
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The textual representation of VID and PID shall be in lower case hexadecimal
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with leading zeroes suppressed. The other compatible strings from the above
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standard binding could also be used, but a device adhering to this binding
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may leave out all except for "usbVID,PID".
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- reg: the number of the USB hub port or the USB host-controller port to which
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this device is attached. The range is 1-255.
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Required properties for hub nodes with device nodes:
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- #address-cells: shall be 1
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- #size-cells: shall be 0
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Required properties for host-controller nodes with device nodes:
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- #address-cells: shall be 1
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- #size-cells: shall be 0
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Example:
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&usb1 { /* host controller */
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#address-cells = <1>;
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#size-cells = <0>;
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hub@1 { /* hub connected to port 1 */
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compatible = "usb5e3,608";
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reg = <1>;
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};
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device@2 { /* device connected to port 2 */
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compatible = "usb123,4567";
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reg = <2>;
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};
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device@3 { /* device connected to port 3 */
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compatible = "usb123,abcd";
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reg = <3>;
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#address-cells = <2>;
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#size-cells = <0>;
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interface@0 { /* interface 0 of configuration 1 */
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compatible = "usbif123,abcd.config1.0";
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reg = <0 1>;
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};
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interface@0,2 { /* interface 0 of configuration 2 */
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compatible = "usbif123,abcd.config2.0";
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reg = <0 2>;
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};
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};
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};
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