usb_gadget.h

linux得一些常用命令,以及linux环境下的c编程

 * this affects the device status reported by the hardware driver.
 * some hardware may not support bus-powered operation, in which
 * case this feature's value can never change.
 *
 * returns zero on success, else negative errno.
 */
static inline int
usb_gadget_clear_selfpowered (struct usb_gadget *gadget)
{
	if (!gadget->ops->set_selfpowered)
		return -EOPNOTSUPP;
	return gadget->ops->set_selfpowered (gadget, 0);
}

/**
 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
 * @gadget:The device which now has VBUS power.
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session starting.  Common responses include
 * resuming the controller, activating the D+ (or D-) pullup to let the
 * host detect that a USB device is attached, and starting to draw power
 * (8mA or possibly more, especially after SET_CONFIGURATION).
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_gadget_vbus_connect(struct usb_gadget *gadget)
{
	if (!gadget->ops->vbus_session)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_session (gadget, 1);
}

/**
 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
 * @gadget:The device whose VBUS usage is being described
 * @mA:How much current to draw, in milliAmperes.  This should be twice
 *	the value listed in the configuration descriptor bMaxPower field.
 *
 * This call is used by gadget drivers during SET_CONFIGURATION calls,
 * reporting how much power the device may consume.  For example, this
 * could affect how quickly batteries are recharged.
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
{
	if (!gadget->ops->vbus_draw)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_draw (gadget, mA);
}

/**
 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
 * @gadget:the device whose VBUS supply is being described
 *
 * This call is used by a driver for an external transceiver (or GPIO)
 * that detects a VBUS power session ending.  Common responses include
 * reversing everything done in usb_gadget_vbus_connect().
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
{
	if (!gadget->ops->vbus_session)
		return -EOPNOTSUPP;
	return gadget->ops->vbus_session (gadget, 0);
}

/**
 * usb_gadget_connect - software-controlled connect to USB host
 * @gadget:the peripheral being connected
 *
 * Enables the D+ (or potentially D-) pullup.  The host will start
 * enumerating this gadget when the pullup is active and a VBUS session
 * is active (the link is powered).  This pullup is always enabled unless
 * usb_gadget_disconnect() has been used to disable it.
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_gadget_connect (struct usb_gadget *gadget)
{
	if (!gadget->ops->pullup)
		return -EOPNOTSUPP;
	return gadget->ops->pullup (gadget, 1);
}

/**
 * usb_gadget_disconnect - software-controlled disconnect from USB host
 * @gadget:the peripheral being disconnected
 *
 * Disables the D+ (or potentially D-) pullup, which the host may see
 * as a disconnect (when a VBUS session is active).  Not all systems
 * support software pullup controls.
 *
 * This routine may be used during the gadget driver bind() call to prevent
 * the peripheral from ever being visible to the USB host, unless later
 * usb_gadget_connect() is called.  For example, user mode components may
 * need to be activated before the system can talk to hosts.
 *
 * Returns zero on success, else negative errno.
 */
static inline int
usb_gadget_disconnect (struct usb_gadget *gadget)
{
	if (!gadget->ops->pullup)
		return -EOPNOTSUPP;
	return gadget->ops->pullup (gadget, 0);
}



/*-------------------------------------------------------------------------*/

/**
 * struct usb_gadget_driver - driver for usb 'slave' devices
 * @function: String describing the gadget's function
 * @speed: Highest speed the driver handles.
 * @bind: Invoked when the driver is bound to a gadget, usually
 * 	after registering the driver.
 * 	At that point, ep0 is fully initialized, and ep_list holds
 * 	the currently-available endpoints.
 * 	Called in a context that permits sleeping.
 * @setup: Invoked for ep0 control requests that aren't handled by
 * 	the hardware level driver. Most calls must be handled by
 * 	the gadget driver, including descriptor and configuration
 * 	management.  The 16 bit members of the setup data are in
 * 	cpu order. Called in_interrupt; this may not sleep.  Driver
 *	queues a response to ep0, or returns negative to stall.
 * @disconnect: Invoked after all transfers have been stopped,
 * 	when the host is disconnected.  May be called in_interrupt; this
 * 	may not sleep.  Some devices can't detect disconnect, so this might
 *	not be called except as part of controller shutdown.
 * @unbind: Invoked when the driver is unbound from a gadget,
 * 	usually from rmmod (after a disconnect is reported).
 * 	Called in a context that permits sleeping.
 * @suspend: Invoked on USB suspend.  May be called in_interrupt.
 * @resume: Invoked on USB resume.  May be called in_interrupt.
 * @driver: Driver model state for this driver.
 *
 * Devices are disabled till a gadget driver successfully bind()s, which
 * means the driver will handle setup() requests needed to enumerate (and
 * meet "chapter 9" requirements) then do some useful work.
 *
 * If gadget->is_otg is true, the gadget driver must provide an OTG
 * descriptor during enumeration, or else fail the bind() call.  In such
 * cases, no USB traffic may flow until both bind() returns without
 * having called usb_gadget_disconnect(), and the USB host stack has
 * initialized.
 *
 * Drivers use hardware-specific knowledge to configure the usb hardware.
 * endpoint addressing is only one of several hardware characteristics that
 * are in descriptors the ep0 implementation returns from setup() calls.
 *
 * Except for ep0 implementation, most driver code shouldn't need change to
 * run on top of different usb controllers.  It'll use endpoints set up by
 * that ep0 implementation.
 *
 * The usb controller driver handles a few standard usb requests.  Those
 * include set_address, and feature flags for devices, interfaces, and
 * endpoints (the get_status, set_feature, and clear_feature requests).
 *
 * Accordingly, the driver's setup() callback must always implement all
 * get_descriptor requests, returning at least a device descriptor and
 * a configuration descriptor.  Drivers must make sure the endpoint
 * descriptors match any hardware constraints. Some hardware also constrains
 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
 *
 * The driver's setup() callback must also implement set_configuration,
 * and should also implement set_interface, get_configuration, and
 * get_interface.  Setting a configuration (or interface) is where
 * endpoints should be activated or (config 0) shut down.
 *
 * (Note that only the default control endpoint is supported.  Neither
 * hosts nor devices generally support control traffic except to ep0.)
 *
 * Most devices will ignore USB suspend/resume operations, and so will
 * not provide those callbacks.  However, some may need to change modes
 * when the host is not longer directing those activities.  For example,
 * local controls (buttons, dials, etc) may need to be re-enabled since
 * the (remote) host can't do that any longer; or an error state might
 * be cleared, to make the device behave identically whether or not
 * power is maintained.
 */
struct usb_gadget_driver {
	char			*function;
	enum usb_device_speed	speed;
	int			(*bind)(struct usb_gadget *);
	void			(*unbind)(struct usb_gadget *);
	int			(*setup)(struct usb_gadget *,
					const struct usb_ctrlrequest *);
	void			(*disconnect)(struct usb_gadget *);
	void			(*suspend)(struct usb_gadget *);
	void			(*resume)(struct usb_gadget *);

	// FIXME support safe rmmod
	struct device_driver	driver;
};



/*-------------------------------------------------------------------------*/

/* driver modules register and unregister, as usual.
 * these calls must be made in a context that can sleep.
 *
 * these will usually be implemented directly by the hardware-dependent
 * usb bus interface driver, which will only support a single driver.
 */

/**
 * usb_gadget_register_driver - register a gadget driver
 * @driver:the driver being registered
 *
 * Call this in your gadget driver's module initialization function,
 * to tell the underlying usb controller driver about your driver.
 * The driver's bind() function will be called to bind it to a
 * gadget.  This function must be called in a context that can sleep.
 */
int usb_gadget_register_driver (struct usb_gadget_driver *driver);

/**
 * usb_gadget_unregister_driver - unregister a gadget driver
 * @driver:the driver being unregistered
 *
 * Call this in your gadget driver's module cleanup function,
 * to tell the underlying usb controller that your driver is
 * going away.  If the controller is connected to a USB host,
 * it will first disconnect().  The driver is also requested
 * to unbind() and clean up any device state, before this procedure
 * finally returns.
 * This function must be called in a context that can sleep.
 */
int usb_gadget_unregister_driver (struct usb_gadget_driver *driver);

/*-------------------------------------------------------------------------*/

/* utility to simplify dealing with string descriptors */

/**
 * struct usb_string - wraps a C string and its USB id
 * @id:the (nonzero) ID for this string
 * @s:the string, in UTF-8 encoding
 *
 * If you're using usb_gadget_get_string(), use this to wrap a string
 * together with its ID.
 */
struct usb_string {
	u8			id;
	const char		*s;
};

/**
 * struct usb_gadget_strings - a set of USB strings in a given language
 * @language:identifies the strings' language (0x0409 for en-us)
 * @strings:array of strings with their ids
 *
 * If you're using usb_gadget_get_string(), use this to wrap all the
 * strings for a given language.
 */
struct usb_gadget_strings {
	u16			language;	/* 0x0409 for en-us */
	struct usb_string	*strings;
};

/* put descriptor for string with that id into buf (buflen >= 256) */
int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf);

/*-------------------------------------------------------------------------*/

/* utility to simplify managing config descriptors */

/* write vector of descriptors into buffer */
int usb_descriptor_fillbuf(void *, unsigned,
		const struct usb_descriptor_header **);

/* build config descriptor from single descriptor vector */
int usb_gadget_config_buf(const struct usb_config_descriptor *config,
	void *buf, unsigned buflen, const struct usb_descriptor_header **desc);

/*-------------------------------------------------------------------------*/

/* utility wrapping a simple endpoint selection policy */

extern struct usb_ep *usb_ep_autoconfig (struct usb_gadget *,
			struct usb_endpoint_descriptor *) __init;

extern void usb_ep_autoconfig_reset (struct usb_gadget *) __init;

#endif  /* __KERNEL__ */

#endif	/* __LINUX_USB_GADGET_H */