57 lines
2.1 KiB
Plaintext
57 lines
2.1 KiB
Plaintext
#
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# USB Gadget support on a system involves
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# (a) a peripheral controller, and
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# (b) the gadget driver using it.
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#
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# NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
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#
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# - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
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# - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
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# - Some systems have both kinds of controllers.
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#
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# With help from a special transceiver and a "Mini-AB" jack, systems with
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# both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
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#
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menuconfig USB_GADGET
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bool "USB Gadget Support"
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help
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USB is a master/slave protocol, organized with one master
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host (such as a PC) controlling up to 127 peripheral devices.
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The USB hardware is asymmetric, which makes it easier to set up:
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you can't connect a "to-the-host" connector to a peripheral.
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U-Boot can run in the host, or in the peripheral. In both cases
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you need a low level bus controller driver, and some software
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talking to it. Peripheral controllers are often discrete silicon,
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or are integrated with the CPU in a microcontroller. The more
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familiar host side controllers have names like "EHCI", "OHCI",
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or "UHCI", and are usually integrated into southbridges on PC
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motherboards.
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Enable this configuration option if you want to run U-Boot inside
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a USB peripheral device. Configure one hardware driver for your
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peripheral/device side bus controller, and a "gadget driver" for
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your peripheral protocol.
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if USB_GADGET
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config USB_GADGET_VBUS_DRAW
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int "Maximum VBUS Power usage (2-500 mA)"
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range 2 500
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default 2
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help
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Some devices need to draw power from USB when they are
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configured, perhaps to operate circuitry or to recharge
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batteries. This is in addition to any local power supply,
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such as an AC adapter or batteries.
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Enter the maximum power your device draws through USB, in
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milliAmperes. The permitted range of values is 2 - 500 mA;
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0 mA would be legal, but can make some hosts misbehave.
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This value will be used except for system-specific gadget
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drivers that have more specific information.
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endif # USB_GADGET
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