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| author | MyungJoo Ham <myungjoo.ham@samsung.com> | 2012-04-20 07:16:26 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-20 18:24:03 +0200 |
| commit | bde68e60b18208978c50c6fb9bdf29826d2887f3 (patch) | |
| tree | 62b48807d48c2454c374bede680c9e9c6cf71a0d /Documentation | |
| parent | Extcon: support multiple states at a device. (diff) | |
| download | linux-bde68e60b18208978c50c6fb9bdf29826d2887f3.tar.xz linux-bde68e60b18208978c50c6fb9bdf29826d2887f3.zip | |
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-extcon | 22 |
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. |