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authorMyungJoo Ham <myungjoo.ham@samsung.com>2012-04-20 14:16:26 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-20 09:24:03 -0700
commitbde68e60b18208978c50c6fb9bdf29826d2887f3 (patch)
tree62b48807d48c2454c374bede680c9e9c6cf71a0d /Documentation
parent806d9dd71ff52ef09764585baaeec23afbb98560 (diff)
downloadlinux-bcache-bde68e60b18208978c50c6fb9bdf29826d2887f3.tar.zst
Extcon: support mutually exclusive relation between cables.
There could be cables that t recannot be attaches simulatenously. Extcon device drivers may express such information via mutually_exclusive in struct extcon_dev. For example, for an extcon device with 16 cables (bits 0 to 15 are available), if mutually_exclusive = { 0x7, 0xC0, 0x81, 0 }, then, the following attachments are prohibitted. {0, 1} {0, 2} {1, 2} {6, 7} {0, 7} and every attachment set that are superset of one of the above. For the detail, please refer to linux/include/linux/extcon.h. The concept is suggested by NeilBrown <neilb@suse.de> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> -- Changes from V5: - Updated sysfs format Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-class-extcon22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-extcon b/Documentation/ABI/testing/sysfs-class-extcon
index 19b18e986a57..20ab361bd8c6 100644
--- a/Documentation/ABI/testing/sysfs-class-extcon
+++ b/Documentation/ABI/testing/sysfs-class-extcon
@@ -15,6 +15,10 @@ Description:
may have both HDMI and Charger attached, or analog audio,
video, and USB cables attached simulteneously.
+ If there are cables mutually exclusive with each other,
+ such binary relations may be expressed with extcon_dev's
+ mutually_exclusive array.
+
What: /sys/class/extcon/.../name
Date: February 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
@@ -73,3 +77,21 @@ Description:
state of cable "x" (integer between 0 and 31) of an extcon
device. The state value is either 0 (detached) or 1
(attached).
+
+What: /sys/class/extcon/.../mutually_exclusive/...
+Date: December 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ Shows the relations of mutually exclusiveness. For example,
+ if the mutually_exclusive array of extcon_dev is
+ {0x3, 0x5, 0xC, 0x0}, the, the output is:
+ # ls mutually_exclusive/
+ 0x3
+ 0x5
+ 0xc
+ #
+
+ Note that mutually_exclusive is a sub-directory of the extcon
+ device and the file names under the mutually_exclusive
+ directory show the mutually-exclusive sets, not the contents
+ of the files.