€•òH      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ0/translations/zh_CN/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ0/translations/zh_TW/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ0/translations/it_IT/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ0/translations/ja_JP/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ0/translations/ko_KR/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ0/translations/sp_SP/input/devices/rotary-encoder”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ<rotary-encoder - a generic driver for GPIO connected devices”h]”hŒ<rotary-encoder - a generic driver for GPIO connected devices”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒJ/var/lib/git/docbuild/linux/Documentation/input/devices/rotary-encoder.rst”h KubhŒ
field_list”“”)”}”(hhh]”hŒfield”“”)”}”(hhh]”(hŒ
field_name”“”)”}”(hŒAuthor”h]”hŒAuthor”…””}”(hhÃhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÁhh¾hŸh¶h K ubhŒ
field_body”“”)”}”(hŒ(Daniel Mack <daniel@caiaq.de>, Feb 2009
”h]”hŒ	paragraph”“”)”}”(hŒ'Daniel Mack <daniel@caiaq.de>, Feb 2009”h]”(hŒDaniel Mack <”…””}”(hhÙhžhhŸNh NubhŒ	reference”“”)”}”(hŒdaniel@caiaq.de”h]”hŒdaniel@caiaq.de”…””}”(hhãhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”Œmailto:daniel@caiaq.de”uh1háhhÙubhŒ>, Feb 2009”…””}”(hhÙhžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KhhÓubah}”(h]”h ]”h"]”h$]”h&]”uh1hÑhh¾ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h¼hŸh¶h Khh¹hžhubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒFunction”h]”hŒFunction”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h KubhØ)”}”(hŒàRotary 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.”h]”hŒàRotary 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.”…””}”(hj   hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K
hj  hžhubhØ)”}”(hŒÀSome encoders have both outputs low in stable states, others also have
a stable state with both outputs high (half-period mode) and some have
a stable state in all steps (quarter-period mode).”h]”hŒÀSome encoders have both outputs low in stable states, others also have
a stable state with both outputs high (half-period mode) and some have
a stable state in all steps (quarter-period mode).”…””}”(hj.  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h Khj  hžhubhØ)”}”(hŒ7The phase diagram of these two outputs look like this::”h]”hŒ6The phase diagram of these two outputs look like this:”…””}”(hj<  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h Khj  hžhubhŒliteral_block”“”)”}”(hXx                  _____       _____       _____
               |     |     |     |     |     |
Channel A  ____|     |_____|     |_____|     |____

               :  :  :  :  :  :  :  :  :  :  :  :
          __       _____       _____       _____
            |     |     |     |     |     |     |
Channel B   |_____|     |_____|     |_____|     |__

               :  :  :  :  :  :  :  :  :  :  :  :
Event          a  b  c  d  a  b  c  d  a  b  c  d

              |<-------->|
                one step

              |<-->|
                one step (half-period mode)

              |<>|
                one step (quarter-period mode)”h]”hXx                  _____       _____       _____
               |     |     |     |     |     |
Channel A  ____|     |_____|     |_____|     |____

               :  :  :  :  :  :  :  :  :  :  :  :
          __       _____       _____       _____
            |     |     |     |     |     |     |
Channel B   |_____|     |_____|     |_____|     |__

               :  :  :  :  :  :  :  :  :  :  :  :
Event          a  b  c  d  a  b  c  d  a  b  c  d

              |<-------->|
                one step

              |<-->|
                one step (half-period mode)

              |<>|
                one step (quarter-period mode)”…””}”hjL  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1jJ  hŸh¶h Khj  hžhubhŒdefinition_list”“”)”}”(hhh]”hŒdefinition_list_item”“”)”}”(hŒOFor more information, please see
https://en.wikipedia.org/wiki/Rotary_encoder

”h]”(hŒterm”“”)”}”(hŒ For more information, please see”h]”hŒ For more information, please see”…””}”(hji  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hŸh¶h K,hjc  ubhŒ
definition”“”)”}”(hhh]”hØ)”}”(hŒ,https://en.wikipedia.org/wiki/Rotary_encoder”h]”hâ)”}”(hj~  h]”hŒ,https://en.wikipedia.org/wiki/Rotary_encoder”…””}”(hj€  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j~  uh1háhj|  ubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K+hjy  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jw  hjc  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K,hj^  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j\  hj  hžhhŸh¶h Nubeh}”(h]”Œfunction”ah ]”h"]”Œfunction”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒEvents / state machine”h]”hŒEvents / state machine”…””}”(hj±  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj®  hžhhŸh¶h K/ubhØ)”}”(hX  In half-period mode, state a) and c) above are used to determine the
rotational direction based on the last stable state. Events are reported in
states b) and d) given that the new stable state is different from the last
(i.e. the rotation was not reversed half-way).”h]”hX  In half-period mode, state a) and c) above are used to determine the
rotational direction based on the last stable state. Events are reported in
states b) and d) given that the new stable state is different from the last
(i.e. the rotation was not reversed half-way).”…””}”(hj¿  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K1hj®  hžhubhØ)”}”(hŒOtherwise, the following apply:”h]”hŒOtherwise, the following apply:”…””}”(hjÍ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K6hj®  hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒgRising edge on channel A, channel B in low state
     This state is used to recognize a clockwise turn
”h]”j]  )”}”(hhh]”jb  )”}”(hŒbRising edge on channel A, channel B in low state
This state is used to recognize a clockwise turn
”h]”(jh  )”}”(hŒ0Rising edge on channel A, channel B in low state”h]”hŒ0Rising edge on channel A, channel B in low state”…””}”(hjí  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hŸh¶h K9hjé  ubjx  )”}”(hhh]”hØ)”}”(hŒ0This state is used to recognize a clockwise turn”h]”hŒ0This state is used to recognize a clockwise turn”…””}”(hjþ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K9hjû  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jw  hjé  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K9hjæ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j\  hjâ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jà  hjÝ  hžhhŸNh Nubjá  )”}”(hŒÃRising 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.
”h]”j]  )”}”(hhh]”jb  )”}”(hŒ¹Rising 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.
”h]”(jh  )”}”(hŒ1Rising edge on channel B, channel A in high state”h]”hŒ1Rising edge on channel B, channel A in high state”…””}”(hj/  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hŸh¶h K=hj+  ubjx  )”}”(hhh]”hØ)”}”(hŒ†When entering this state, the encoder is put into 'armed' state,
meaning that there it has seen half the way of a one-step transition.”h]”hŒŠWhen entering this state, the encoder is put into â€˜armedâ€™ state,
meaning that there it has seen half the way of a one-step transition.”…””}”(hj@  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K<hj=  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jw  hj+  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K=hj(  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j\  hj$  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jà  hjÝ  hžhhŸNh Nubjá  )”}”(hŒqFalling edge on channel A, channel B in high state
     This state is used to recognize a counter-clockwise turn
”h]”j]  )”}”(hhh]”jb  )”}”(hŒlFalling edge on channel A, channel B in high state
This state is used to recognize a counter-clockwise turn
”h]”(jh  )”}”(hŒ2Falling edge on channel A, channel B in high state”h]”hŒ2Falling edge on channel A, channel B in high state”…””}”(hjq  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hŸh¶h K@hjm  ubjx  )”}”(hhh]”hØ)”}”(hŒ8This state is used to recognize a counter-clockwise turn”h]”hŒ8This state is used to recognize a counter-clockwise turn”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K@hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jw  hjm  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K@hjj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j\  hjf  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jà  hjÝ  hžhhŸNh Nubjá  )”}”(hŒìFalling edge on channel B, channel A in low state
     Parking position. If the encoder enters this state, a full transition
     should have happened, unless it flipped back on half the way. The
     'armed' state tells us about that.
”h]”j]  )”}”(hhh]”jb  )”}”(hŒÝFalling edge on channel B, channel A in low state
Parking position. If the encoder enters this state, a full transition
should have happened, unless it flipped back on half the way. The
'armed' state tells us about that.
”h]”(jh  )”}”(hŒ1Falling edge on channel B, channel A in low state”h]”hŒ1Falling edge on channel B, channel A in low state”…””}”(hj³  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jg  hŸh¶h KEhj¯  ubjx  )”}”(hhh]”hØ)”}”(hŒªParking position. If the encoder enters this state, a full transition
should have happened, unless it flipped back on half the way. The
'armed' state tells us about that.”h]”hŒ®Parking position. If the encoder enters this state, a full transition
should have happened, unless it flipped back on half the way. The
â€˜armedâ€™ state tells us about that.”…””}”(hjÄ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KChjÁ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jw  hj¯  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h KEhj¬  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j\  hj¨  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jà  hjÝ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œ
loweralpha”Œprefix”hŒsuffix”Œ)”uh1jÛ  hj®  hžhhŸh¶h K8ubeh}”(h]”Œevents-state-machine”ah ]”h"]”Œevents / state machine”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K/ubh¢)”}”(hhh]”(h§)”}”(hŒPlatform requirements”h]”hŒPlatform requirements”…””}”(hj   hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjý  hžhhŸh¶h KHubhØ)”}”(hŒ®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.”h]”hŒ®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.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KJhjý  hžhubeh}”(h]”Œplatform-requirements”ah ]”h"]”Œplatform requirements”ah$]”h&]”uh1h¡hh£hžhhŸh¶h KHubh¢)”}”(hhh]”(h§)”}”(hŒBoard integration”h]”hŒBoard integration”…””}”(hj'  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj$  hžhhŸh¶h KPubhØ)”}”(hX2  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. Because the driver uses generic device properties, this can
be done either via device tree, ACPI, or using static board files, like in
example below:”h]”hX6  To use this driver in your system, register a platform_device with the
name â€˜rotary-encoderâ€™ and associate the IRQs and some specific platform
data with it. Because the driver uses generic device properties, this can
be done either via device tree, ACPI, or using static board files, like in
example below:”…””}”(hj5  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KRhj$  hžhubjK  )”}”(hXò  /* board support file example */

#include <linux/input.h>
#include <linux/gpio/machine.h>
#include <linux/property.h>

#define GPIO_ROTARY_A 1
#define GPIO_ROTARY_B 2

static struct gpiod_lookup_table rotary_encoder_gpios = {
        .dev_id = "rotary-encoder.0",
        .table = {
                GPIO_LOOKUP_IDX("gpio-0",
                                GPIO_ROTARY_A, NULL, 0, GPIO_ACTIVE_LOW),
                GPIO_LOOKUP_IDX("gpio-0",
                                GPIO_ROTARY_B, NULL, 1, GPIO_ACTIVE_HIGH),
                { },
        },
};

static const struct property_entry rotary_encoder_properties[] = {
        PROPERTY_ENTRY_U32("rotary-encoder,steps-per-period", 24),
        PROPERTY_ENTRY_U32("linux,axis",                      ABS_X),
        PROPERTY_ENTRY_U32("rotary-encoder,relative_axis",    0),
        { },
};

static const struct software_node rotary_encoder_node = {
        .properties = rotary_encoder_properties,
};

static struct platform_device rotary_encoder_device = {
        .name           = "rotary-encoder",
        .id             = 0,
};

...

gpiod_add_lookup_table(&rotary_encoder_gpios);
device_add_software_node(&rotary_encoder_device.dev, &rotary_encoder_node);
platform_device_register(&rotary_encoder_device);

...”h]”hXò  /* board support file example */

#include <linux/input.h>
#include <linux/gpio/machine.h>
#include <linux/property.h>

#define GPIO_ROTARY_A 1
#define GPIO_ROTARY_B 2

static struct gpiod_lookup_table rotary_encoder_gpios = {
        .dev_id = "rotary-encoder.0",
        .table = {
                GPIO_LOOKUP_IDX("gpio-0",
                                GPIO_ROTARY_A, NULL, 0, GPIO_ACTIVE_LOW),
                GPIO_LOOKUP_IDX("gpio-0",
                                GPIO_ROTARY_B, NULL, 1, GPIO_ACTIVE_HIGH),
                { },
        },
};

static const struct property_entry rotary_encoder_properties[] = {
        PROPERTY_ENTRY_U32("rotary-encoder,steps-per-period", 24),
        PROPERTY_ENTRY_U32("linux,axis",                      ABS_X),
        PROPERTY_ENTRY_U32("rotary-encoder,relative_axis",    0),
        { },
};

static const struct software_node rotary_encoder_node = {
        .properties = rotary_encoder_properties,
};

static struct platform_device rotary_encoder_device = {
        .name           = "rotary-encoder",
        .id             = 0,
};

...

gpiod_add_lookup_table(&rotary_encoder_gpios);
device_add_software_node(&rotary_encoder_device.dev, &rotary_encoder_node);
platform_device_register(&rotary_encoder_device);

...”…””}”hjC  sbah}”(h]”h ]”h"]”h$]”h&]”jZ  j[  uh1jJ  hŸh¶h KZhj$  hžhubhØ)”}”(hŒ_Please consult device tree binding documentation to see all properties
supported by the driver.”h]”hŒ_Please consult device tree binding documentation to see all properties
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