drivers/usb/gadget/legacy/printer.c

Source file repositories/reference/linux-study-clean/drivers/usb/gadget/legacy/printer.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/gadget/legacy/printer.c
Extension
.c
Size
5902 bytes
Lines
227
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!opts->pnp_string) {
			ret = -ENOMEM;
			goto fail_put_func_inst;
		}
		opts->pnp_string_allocated = true;
		/*
		 * we don't free this memory in case of error
		 * as printer cleanup func will do this for us
		 */
	} else {
		opts->pnp_string = pnp_string;
	}

	ret = usb_string_ids_tab(cdev, strings);
	if (ret < 0)
		goto fail_put_func_inst;

	device_desc.iManufacturer = strings[USB_GADGET_MANUFACTURER_IDX].id;
	device_desc.iProduct = strings[USB_GADGET_PRODUCT_IDX].id;
	device_desc.iSerialNumber = strings[USB_GADGET_SERIAL_IDX].id;

	if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
		struct usb_descriptor_header *usb_desc;

		usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
		if (!usb_desc) {
			ret = -ENOMEM;
			goto fail_put_func_inst;
		}
		usb_otg_descriptor_init(cdev->gadget, usb_desc);
		otg_desc[0] = usb_desc;
		otg_desc[1] = NULL;
	}

	ret = usb_add_config(cdev, &printer_cfg_driver, printer_do_config);
	if (ret)
		goto fail_free_otg_desc;

	usb_composite_overwrite_options(cdev, &coverwrite);
	return ret;

fail_free_otg_desc:
	kfree(otg_desc[0]);
	otg_desc[0] = NULL;
fail_put_func_inst:
	usb_put_function_instance(fi_printer);
	return ret;
}

static int printer_unbind(struct usb_composite_dev *cdev)
{
	usb_put_function(f_printer);
	usb_put_function_instance(fi_printer);

	kfree(otg_desc[0]);
	otg_desc[0] = NULL;

	return 0;
}

static struct usb_composite_driver printer_driver = {
	.name           = shortname,
	.dev            = &device_desc,
	.strings        = dev_strings,
	.max_speed      = USB_SPEED_SUPER,
	.bind		= printer_bind,
	.unbind		= printer_unbind,
};

module_usb_composite_driver(printer_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Craig Nadler");
MODULE_LICENSE("GPL");

Annotation

Implementation Notes