summaryrefslogtreecommitdiff
path: root/Documentation/ABI
diff options
context:
space:
mode:
authorRichard Leitner <richard.leitner@skidata.com>2018-03-20 11:17:13 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-22 13:07:05 +0100
commit1cbd53c8cd85a63383a075347abee8f6e3f14fbe (patch)
treef80b57ca914df69f6d4cfecb0515bfbb5a40c5e3 /Documentation/ABI
parente3cb7bde9a6a8bfdee5917facf00afb98fee1821 (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-usb10
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>