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

Matthew Garrett
2012-03-12T21:45:46Z

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.

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
--
1.7.9.3

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