diff options
| author | Richard Leitner <richard.leitner@skidata.com> | 2018-03-20 11:17:13 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-22 13:07:05 +0100 |
| commit | 1cbd53c8cd85a63383a075347abee8f6e3f14fbe (patch) | |
| tree | f80b57ca914df69f6d4cfecb0515bfbb5a40c5e3 /Documentation/ABI | |
| parent | e3cb7bde9a6a8bfdee5917facf00afb98fee1821 (diff) | |
usb: core: introduce per-port over-current counters
For some userspace applications information on the number of
over-current conditions at specific USB hub ports is relevant.
In our case we have a series of USB hardware (using the cp210x driver)
which communicates using a proprietary protocol. These devices sometimes
trigger an over-current situation on some hubs. In case of such an
over-current situation the USB devices offer an interface for reducing
the max used power. As these conditions are quite rare and imply
performance reductions of the device we don't want to reduce the max
power always.
Therefore give user-space applications the possibility to react
adequately by introducing an over_current_counter in the usb port struct
which is exported via sysfs.
Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 0bd731cbb50c..c702c78f24d8 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -189,6 +189,16 @@ Description: The file will read "hotplug", "wired" and "not used" if the information is available, and "unknown" otherwise. +What: /sys/bus/usb/devices/.../(hub interface)/portX/over_current_count +Date: February 2018 +Contact: Richard Leitner <richard.leitner@skidata.com> +Description: + Most hubs are able to detect over-current situations on their + ports and report them to the kernel. This attribute is to expose + the number of over-current situation occurred on a specific port + to user space. This file will contain an unsigned 32 bit value + which wraps to 0 after its maximum is reached. + What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit Date: November 2015 Contact: Lu Baolu <baolu.lu@linux.intel.com> |