-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
…/git/dtor/input * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (22 commits) Input: i8042 - add HP DV9700 to the noloop list Input: arrange drivers/input/misc/Makefile in alphabetical order Input: add AD7879 Touchscreen driver Input: add AD7877 touchscreen driver Input: bf54x-keys - fix typo in warning Input: add driver for S1 button of rb532 Input: generic driver for rotary encoders on GPIOs Input: hilkbd - fix crash when removing hilkbd module Input: atkbd - add quirk for Fujitsu Siemens Amilo PA 1510 Input: atkbd - consolidate force release quirk setup Input: add accelerated touchscreen support for Marvell Zylonite Input: ucb1400_ts, mainstone-wm97xx - add BTN_TOUCH events Input: wm97xx - use disable_irq_nosync() for Mainstone Input: wm97xx - add BTN_TOUCH event to wm97xx to use it with Android Input: fix polling of /proc/bus/input/devices Input: psmouse - add newline to OLPC HGPK touchpad debugging Input: ati_remote2 - check module params Input: ati_remote2 - add per device attrs Input: ati_remote2 - complete suspend support Input: stop autorepeat timer on key release ...
- Loading branch information
Showing
28 changed files
with
3,062 additions
and
200 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,101 @@ | ||
rotary-encoder - a generic driver for GPIO connected devices | ||
Daniel Mack <daniel@caiaq.de>, Feb 2009 | ||
|
||
0. Function | ||
----------- | ||
|
||
Rotary encoders are devices which are connected to the CPU or other | ||
peripherals with two wires. The outputs are phase-shifted by 90 degrees | ||
and by triggering on falling and rising edges, the turn direction can | ||
be determined. | ||
|
||
The phase diagram of these two outputs look like this: | ||
|
||
_____ _____ _____ | ||
| | | | | | | ||
Channel A ____| |_____| |_____| |____ | ||
|
||
: : : : : : : : : : : : | ||
__ _____ _____ _____ | ||
| | | | | | | | ||
Channel B |_____| |_____| |_____| |__ | ||
|
||
: : : : : : : : : : : : | ||
Event a b c d a b c d a b c d | ||
|
||
|<-------->| | ||
one step | ||
|
||
|
||
For more information, please see | ||
http://en.wikipedia.org/wiki/Rotary_encoder | ||
|
||
|
||
1. Events / state machine | ||
------------------------- | ||
|
||
a) Rising edge on channel A, channel B in low state | ||
This state is used to recognize a clockwise turn | ||
|
||
b) Rising edge on channel B, channel A in high state | ||
When entering this state, the encoder is put into 'armed' state, | ||
meaning that there it has seen half the way of a one-step transition. | ||
|
||
c) Falling edge on channel A, channel B in high state | ||
This state is used to recognize a counter-clockwise turn | ||
|
||
d) Falling edge on channel B, channel A in low state | ||
Parking position. If the encoder enters this state, a full transition | ||
should have happend, unless it flipped back on half the way. The | ||
'armed' state tells us about that. | ||
|
||
2. Platform requirements | ||
------------------------ | ||
|
||
As there is no hardware dependent call in this driver, the platform it is | ||
used with must support gpiolib. Another requirement is that IRQs must be | ||
able to fire on both edges. | ||
|
||
|
||
3. Board integration | ||
-------------------- | ||
|
||
To use this driver in your system, register a platform_device with the | ||
name 'rotary-encoder' and associate the IRQs and some specific platform | ||
data with it. | ||
|
||
struct rotary_encoder_platform_data is declared in | ||
include/linux/rotary-encoder.h and needs to be filled with the number of | ||
steps the encoder has and can carry information about externally inverted | ||
signals (because of used invertig buffer or other reasons). | ||
|
||
Because GPIO to IRQ mapping is platform specific, this information must | ||
be given in seperately to the driver. See the example below. | ||
|
||
---------<snip>--------- | ||
|
||
/* board support file example */ | ||
|
||
#include <linux/input.h> | ||
#include <linux/rotary_encoder.h> | ||
|
||
#define GPIO_ROTARY_A 1 | ||
#define GPIO_ROTARY_B 2 | ||
|
||
static struct rotary_encoder_platform_data my_rotary_encoder_info = { | ||
.steps = 24, | ||
.axis = ABS_X, | ||
.gpio_a = GPIO_ROTARY_A, | ||
.gpio_b = GPIO_ROTARY_B, | ||
.inverted_a = 0, | ||
.inverted_b = 0, | ||
}; | ||
|
||
static struct platform_device rotary_encoder_device = { | ||
.name = "rotary-encoder", | ||
.id = 0, | ||
.dev = { | ||
.platform_data = &my_rotary_encoder_info, | ||
} | ||
}; | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.