From f98e0640c5c6b8bb00336dae8d06ede862754c28 Mon Sep 17 00:00:00 2001 From: Bastien Nocera Date: Thu, 2 Mar 2023 11:55:53 +0100 Subject: USB: core: Add wireless_status sysfs attribute MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a wireless_status sysfs attribute to USB devices to keep track of whether a USB device that's comprised of a receiver dongle and an emitter device over a, most of the time proprietary, wireless link has its emitter connected or disconnected. This will be used by user-space OS components to determine whether the battery-powered part of the device is wirelessly connected or not, allowing, for example: - upower to hide the battery for devices where the device is turned off but the receiver plugged in, rather than showing 0%, or other values that could be confusing to users - Pipewire to hide a headset from the list of possible inputs or outputs or route audio appropriately if the headset is suddenly turned off, or turned on - libinput to determine whether a keyboard or mouse is present when its receiver is plugged in. This is done at the USB interface level as: - the interface on which the wireless status is detected is sometimes not the same as where it could be consumed (eg. the audio interface on a headset dongle will still appear even if the headset is turned off), and we cannot have synchronisation of status across subsystems. - this behaviour is not specific to HID devices, even if the protocols used to determine whether or not the remote device is connected can be HID. This is not an attribute that is meant to replace protocol specific APIs, such as the ones available for WWAN, WLAN/Wi-Fi, or Bluetooth or any other sort of networking, but solely for wireless devices with an ad-hoc “lose it and your device is e-waste” receiver dongle. The USB interface will only be exporting the wireless_status sysfs attribute if it gets set through the API exported in the next commit. Signed-off-by: Bastien Nocera Acked-by: Greg Kroah-Hartman Acked-by: Alan Stern Link: https://lore.kernel.org/r/20230302105555.51417-4-hadess@hadess.net Signed-off-by: Benjamin Tissoires --- include/linux/usb.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux') diff --git a/include/linux/usb.h b/include/linux/usb.h index 9642ee02d713..eee54cc961b4 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -170,6 +170,12 @@ usb_find_last_int_out_endpoint(struct usb_host_interface *alt, return usb_find_common_endpoints_reverse(alt, NULL, NULL, NULL, int_out); } +enum usb_wireless_status { + USB_WIRELESS_STATUS_NA = 0, + USB_WIRELESS_STATUS_DISCONNECTED, + USB_WIRELESS_STATUS_CONNECTED, +}; + /** * struct usb_interface - what usb device drivers talk to * @altsetting: array of interface structures, one for each alternate @@ -203,6 +209,8 @@ usb_find_last_int_out_endpoint(struct usb_host_interface *alt, * @reset_ws: Used for scheduling resets from atomic context. * @resetting_device: USB core reset the device, so use alt setting 0 as * current; needs bandwidth alloc after reset. + * @wireless_status: if the USB device uses a receiver/emitter combo, whether + * the emitter is connected. * * USB device drivers attach to interfaces on a physical device. Each * interface encapsulates a single high level function, such as feeding @@ -253,6 +261,7 @@ struct usb_interface { unsigned needs_binding:1; /* needs delayed unbind/rebind */ unsigned resetting_device:1; /* true: bandwidth alloc after reset */ unsigned authorized:1; /* used for interface authorization */ + enum usb_wireless_status wireless_status; struct device dev; /* interface specific device info */ struct device *usb_dev; -- cgit v1.2.3 From 0a4db185f0788dfc828512d0004c468921bf6c0a Mon Sep 17 00:00:00 2001 From: Bastien Nocera Date: Thu, 2 Mar 2023 11:55:54 +0100 Subject: USB: core: Add API to change the wireless_status This adds the API that allows device specific drivers to tell user-space about whether the wireless device is connected to its receiver dongle. See "USB: core: Add wireless_status sysfs attribute" for a detailed explanation of what this attribute should be used for. Signed-off-by: Bastien Nocera Acked-by: Greg Kroah-Hartman Acked-by: Alan Stern Link: https://lore.kernel.org/r/20230302105555.51417-5-hadess@hadess.net Signed-off-by: Benjamin Tissoires --- include/linux/usb.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/usb.h b/include/linux/usb.h index eee54cc961b4..6dfd59d3d695 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -262,6 +262,7 @@ struct usb_interface { unsigned resetting_device:1; /* true: bandwidth alloc after reset */ unsigned authorized:1; /* used for interface authorization */ enum usb_wireless_status wireless_status; + struct work_struct wireless_status_work; struct device dev; /* interface specific device info */ struct device *usb_dev; @@ -896,6 +897,10 @@ static inline int usb_interface_claimed(struct usb_interface *iface) extern void usb_driver_release_interface(struct usb_driver *driver, struct usb_interface *iface); + +int usb_set_wireless_status(struct usb_interface *iface, + enum usb_wireless_status status); + const struct usb_device_id *usb_match_id(struct usb_interface *interface, const struct usb_device_id *id); extern int usb_match_one_id(struct usb_interface *interface, -- cgit v1.2.3 From 539adfedbd2d5cda2f9e2d83b35b364834b67d58 Mon Sep 17 00:00:00 2001 From: Bastien Nocera Date: Wed, 5 Apr 2023 11:27:54 +0200 Subject: USB: core: Fix docs warning caused by wireless_status feature Fix wrongly named 'dev' parameter in doc block, should have been iface: drivers/usb/core/message.c:1939: warning: Function parameter or member 'iface' not described in 'usb_set_wireless_status' drivers/usb/core/message.c:1939: warning: Excess function parameter 'dev' description in 'usb_set_wireless_status' And fix missing struct member doc in kernel API, and reorder to match struct: include/linux/usb.h:270: warning: Function parameter or member 'wireless_status_work' not described in 'usb_interface' Reported-by: Stephen Rothwell Link: https://lore.kernel.org/linux-next/20230405114807.5a57bf46@canb.auug.org.au/T/#t Fixes: 0a4db185f078 ("USB: core: Add API to change the wireless_status") Signed-off-by: Bastien Nocera Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20230405092754.36579-1-hadess@hadess.net [bentiss: fix checkpatch warning] Signed-off-by: Benjamin Tissoires --- include/linux/usb.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/usb.h b/include/linux/usb.h index 6dfd59d3d695..0a81e0f5beb4 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -203,14 +203,16 @@ enum usb_wireless_status { * following a reset or suspend operation it doesn't support. * @authorized: This allows to (de)authorize individual interfaces instead * a whole device in contrast to the device authorization. + * @wireless_status: if the USB device uses a receiver/emitter combo, whether + * the emitter is connected. + * @wireless_status_work: Used for scheduling wireless status changes + * from atomic context. * @dev: driver model's view of this device * @usb_dev: if an interface is bound to the USB major, this will point * to the sysfs representation for that device. * @reset_ws: Used for scheduling resets from atomic context. * @resetting_device: USB core reset the device, so use alt setting 0 as * current; needs bandwidth alloc after reset. - * @wireless_status: if the USB device uses a receiver/emitter combo, whether - * the emitter is connected. * * USB device drivers attach to interfaces on a physical device. Each * interface encapsulates a single high level function, such as feeding -- cgit v1.2.3