Re: [linux-usb-devel] [RFC] USB: driver for iphone charging

[Alan Stern <stern@rowland.harvard.edu>]

On Fri, 24 Aug 2007, Greg KH wrote:

> Can someone with a iphone test this out?  If you look at how the
> berry_charge driver does it, the set_config stuff happens after the
> magic command.  As I don't have an iphone, nor have I ever seen any
> dumps of the command streams, I don't really know if the set_config
> message really is necessary or not.

You know, now that I think back on it, it may be that the Set-Config
really does have to come after the magic command.  Perhaps it triggers
the changeover.  In which case the subroutine should look like this:

static int iphone_probe(struct usb_interface *intf,
			const struct usb_device_id *id)
{
	struct usb_device *udev = interface_to_usbdev(intf);
	int rc;

	if (udev->actconfig->desc.bConfigurationValue != 3) {
		dbg(&udev->dev, "Sending magic comand\n");
		rc = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
				0x40, (USB_DIR_OUT | USB_TYPE_VENDOR |
					USB_RECIP_DEVICE),
				0x6400, 0, NULL, 0, 1000);
		if (rc)
			dev_err(&udev->dev, "Command failed: %d\n", rc);
		else {
			dbg(&udev->dev, "Calling set_configuration\n");
			rc = usb_driver_set_configuration(udev, 3);
			if (rc)
				dev_err(&udev->dev, "Set-Config failed: %d\n",
						rc);
		}
	}

	/* we don't really want to bind to the device, userspace programs can
	 * handle the syncing just fine, so get outta here. */
	return -ENODEV;
}

However Oliver's point is well taken.  This simple sort of manipulation
could easily be done by a user program, started up by udev.

Alan Stern

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