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authorMyungJoo Ham <myungjoo.ham@samsung.com>2012-04-20 07:16:25 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-20 18:23:37 +0200
commit806d9dd71ff52ef09764585baaeec23afbb98560 (patch)
treee81291b139bac10e08d1cb376a22cac5c89a3b65 /Documentation/ABI/testing
parentExtcon: support notification based on the state changes. (diff)
downloadlinux-806d9dd71ff52ef09764585baaeec23afbb98560.tar.xz
linux-806d9dd71ff52ef09764585baaeec23afbb98560.zip
Extcon: support multiple states at a device.
One switch device (e.g., MUIC(MAX8997, MAX77686, ...), and some 30-pin devices) may have multiple cables attached. For example, one 30-pin port may inhabit a USB cable, an HDMI cable, and a mic. Thus, one switch device requires multiple state bits each representing a type of cable. For such purpose, we use the 32bit state variable; thus, up to 32 different type of cables may be defined for a switch device. The list of possible cables is defined by the array of cable names in the switch_dev struct given to the class. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> -- Changes from V7 - Bugfixed in _call_per_cable() (incorrect nb) (Chanwoo Choi) - Compiler error in header for !CONFIG_EXTCON (Chanwoo Choi) Changes from V5 - Sysfs style reformed: subdirectory per cable. - Updated standard cable names - Removed unnecessary printf - Bugfixes after testing Changes from V4 - Bugfixes after more testing at Exynos4412 boards with userspace processses. Changes from V3 - Bugfixes after more testing at Exynos4412 boards. Changes from V2 - State can be stored by user - Documentation updated Changes from RFC - Switch is renamed to extcon - Added kerneldoc comments - Added APIs to support "standard" cable names - Added helper APIs to support notifier block registration with cable name. - Regrouped function list in the header file. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI/testing')
-rw-r--r--Documentation/ABI/testing/sysfs-class-extcon63
1 files changed, 56 insertions, 7 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-extcon b/Documentation/ABI/testing/sysfs-class-extcon
index 59a4b1c708d5..19b18e986a57 100644
--- a/Documentation/ABI/testing/sysfs-class-extcon
+++ b/Documentation/ABI/testing/sysfs-class-extcon
@@ -1,5 +1,5 @@
What: /sys/class/extcon/.../
-Date: December 2011
+Date: February 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
Provide a place in sysfs for the extcon objects.
@@ -7,8 +7,16 @@ Description:
The name of extcon object denoted as ... is the name given
with extcon_dev_register.
+ One extcon device denotes a single external connector
+ port. An external connector may have multiple cables
+ attached simultaneously. Many of docks, cradles, and
+ accessory cables have such capability. For example,
+ the 30-pin port of Nuri board (/arch/arm/mach-exynos)
+ may have both HDMI and Charger attached, or analog audio,
+ video, and USB cables attached simulteneously.
+
What: /sys/class/extcon/.../name
-Date: December 2011
+Date: February 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/extcon/.../name shows the name of the extcon
@@ -17,10 +25,51 @@ Description:
this sysfs node.
What: /sys/class/extcon/.../state
-Date: December 2011
+Date: February 2012
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/extcon/.../state shows and stores the cable
+ attach/detach information of the corresponding extcon object.
+ If the extcon object has an optional callback "show_state"
+ defined, the showing function is overriden with the optional
+ callback.
+
+ If the default callback for showing function is used, the
+ format is like this:
+ # cat state
+ USB_OTG=1
+ HDMI=0
+ TA=1
+ EAR_JACK=0
+ #
+ In this example, the extcon device have USB_OTG and TA
+ cables attached and HDMI and EAR_JACK cables detached.
+
+ In order to update the state of an extcon device, enter a hex
+ state number starting with 0x.
+ echo 0xHEX > state
+
+ This updates the whole state of the extcon dev.
+ Inputs of all the methods are required to meet the
+ mutually_exclusive contidions if they exist.
+
+ It is recommended to use this "global" state interface if
+ you need to enter the value atomically. The later state
+ interface associated with each cable cannot update
+ multiple cable states of an extcon device simultaneously.
+
+What: /sys/class/extcon/.../cable.x/name
+Date: February 2012
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/extcon/.../cable.x/name shows the name of cable
+ "x" (integer between 0 and 31) of an extcon device.
+
+What: /sys/class/extcon/.../cable.x/state
+Date: February 2012
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
- The /sys/class/extcon/.../state shows the cable attach/detach
- information of the corresponding extcon object. If the extcon
- objecct has an optional callback "show_state" defined, the
- callback will provide the name with this sysfs node.
+ The /sys/class/extcon/.../cable.x/name shows and stores the
+ state of cable "x" (integer between 0 and 31) of an extcon
+ device. The state value is either 0 (detached) or 1
+ (attached).