Re: [PATCH V2 3/4] usb: Bind devices to ACPI devices when possible

[Lan Tianyu <tianyu.lan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

On 2012年03月13日 05:45, Matthew Garrett wrote:
> Built-in USB devices will typically have a representation in the system
> ACPI tables. Add support for binding the two together so the USB code can
> make use of the associated methods.
hi Matthew:
	acpi glue framework only can cover situation that the port has been
connected with some device. so without device, no acpi handle can be used to
access "UPC" and "PLD".
	Whether the usb port is user-visible or not is also useful when there
is no device. For example, if it is known that the usb port is not user-visible
and connectable. The usb hub port can be power-off.
	So usb/acpi binding should consider those usb ports without plugging device.
Does this make sense? :)
	
>
> Signed-off-by: Matthew Garrett<mjg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>
> Add a is_usb_device() check to make sure that we're looking at an actual
> USB device rather than an interface.
>
>   drivers/usb/core/Makefile   |    1 +
>   drivers/usb/core/usb-acpi.c |   60 +++++++++++++++++++++++++++++++++++++++++++
>   drivers/usb/core/usb.c      |    6 +++++
>   drivers/usb/core/usb.h      |    7 +++++
>   4 files changed, 74 insertions(+)
>   create mode 100644 drivers/usb/core/usb-acpi.c
>
> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
> index 507a4e1..9268ddb 100644
> --- a/drivers/usb/core/Makefile
> +++ b/drivers/usb/core/Makefile
> @@ -10,5 +10,6 @@ usbcore-y += devio.o notify.o generic.o quirks.o devices.o
>
>   usbcore-$(CONFIG_PCI)		+= hcd-pci.o
>   usbcore-$(CONFIG_USB_DEVICEFS)	+= inode.o
> +usbcore-$(CONFIG_ACPI)		+= usb-acpi.o
>
>   obj-$(CONFIG_USB)		+= usbcore.o
> diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
> new file mode 100644
> index 0000000..cab5cb7
> --- /dev/null
> +++ b/drivers/usb/core/usb-acpi.c
> @@ -0,0 +1,60 @@
> +/*
> + * USB-ACPI glue code
> + *
> + * Copyright 2012 Red Hat<mjg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the Free
> + * Software Foundation, version 2.
> + *
> + */
> +#include<linux/module.h>
> +#include<linux/usb.h>
> +#include<linux/device.h>
> +#include<linux/errno.h>
> +#include<linux/kernel.h>
> +#include<linux/acpi.h>
> +#include<linux/pci.h>
> +#include<acpi/acpi_bus.h>
> +
> +#include "usb.h"
> +
> +static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
> +{
> +	struct usb_device *udev;
> +	struct device *parent;
> +	acpi_handle *parent_handle;
> +
> +	if (!is_usb_device(dev))
> +		return -ENODEV;
> +
> +	udev = to_usb_device(dev);
> +	parent = dev->parent;
> +	parent_handle = DEVICE_ACPI_HANDLE(parent);
> +
> +	if (!parent_handle)
> +		return -ENODEV;
> +
> +	*handle = acpi_get_child(parent_handle, udev->portnum);
> +
> +	if (!*handle)
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +static struct acpi_bus_type usb_acpi_bus = {
> +	.bus =&usb_bus_type,
> +	.find_bridge = NULL,
> +	.find_device = usb_acpi_find_device,
> +};
> +
> +int usb_acpi_register(void)
> +{
> +	return register_acpi_bus_type(&usb_acpi_bus);
> +}
> +
> +void usb_acpi_unregister(void)
> +{
> +	unregister_acpi_bus_type(&usb_acpi_bus);
> +}
> diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
> index 8ca9f99..ce47e3f 100644
> --- a/drivers/usb/core/usb.c
> +++ b/drivers/usb/core/usb.c
> @@ -1015,6 +1015,9 @@ static int __init usb_init(void)
>   	if (retval)
>   		goto out;
>
> +	retval = usb_acpi_register();
> +	if (retval)
> +		goto acpi_register_failed;
>   	retval = bus_register(&usb_bus_type);
>   	if (retval)
>   		goto bus_register_failed;
> @@ -1054,6 +1057,8 @@ major_init_failed:
>   bus_notifier_failed:
>   	bus_unregister(&usb_bus_type);
>   bus_register_failed:
> +	usb_acpi_unregister();
> +acpi_register_failed:
>   	usb_debugfs_cleanup();
>   out:
>   	return retval;
> @@ -1076,6 +1081,7 @@ static void __exit usb_exit(void)
>   	usb_hub_cleanup();
>   	bus_unregister_notifier(&usb_bus_type,&usb_bus_nb);
>   	bus_unregister(&usb_bus_type);
> +	usb_acpi_unregister();
>   	usb_debugfs_cleanup();
>   }
>
> diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
> index 45e8479..636d98e 100644
> --- a/drivers/usb/core/usb.h
> +++ b/drivers/usb/core/usb.h
> @@ -155,3 +155,10 @@ extern void usb_notify_remove_device(struct usb_device *udev);
>   extern void usb_notify_add_bus(struct usb_bus *ubus);
>   extern void usb_notify_remove_bus(struct usb_bus *ubus);
>
> +#ifdef CONFIG_ACPI
> +extern int usb_acpi_register(void);
> +extern void usb_acpi_unregister(void);
> +#else
> +static inline int usb_acpi_register(void) { return 0; };
> +static inline void usb_acpi_unregister(void) { };
> +#endif

-- 
Best Regards
Tianyu Lan
linux kernel enabling team
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