From 73a1a4ca7ee7fe68449c28e8e3225599badd49a5 Mon Sep 17 00:00:00 2001 From: Syed Rafiuddin Date: Mon, 3 Sep 2012 15:35:12 +0530 Subject: 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 (cherry picked from commit bde68e60b18208978c50c6fb9bdf29826d2887f3) Signed-off-by: MyungJoo Ham Signed-off-by: Kyungmin Park -- Changes from V5: - Updated sysfs format Signed-off-by: Greg Kroah-Hartman Change-Id: I5849ba647e63e44525c9113a14a6d29fb51f6d64 Signed-off-by: Syed Rafiuddin Reviewed-on: http://git-master/r/130611 Reviewed-by: Laxman Dewangan --- Documentation/ABI/testing/sysfs-class-extcon | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'Documentation') 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 @@ -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 +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. -- cgit v1.2.3