€•:      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”Œ2/translations/zh_CN/driver-api/driver-model/device”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$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ2/translations/zh_TW/driver-api/driver-model/device”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ2/translations/it_IT/driver-api/driver-model/device”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ2/translations/ja_JP/driver-api/driver-model/device”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ2/translations/ko_KR/driver-api/driver-model/device”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ2/translations/sp_SP/driver-api/driver-model/device”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒThe Basic Device Structure”h]”hŒThe Basic Device Structure”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒL/var/lib/git/docbuild/linux/Documentation/driver-api/driver-model/device.rst”h KubhŒ	paragraph”“”)”}”(hŒ(See the kerneldoc for the struct device.”h]”hŒ(See the kerneldoc for the struct device.”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒProgramming Interface”h]”hŒProgramming Interface”…””}”(hhÊhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hhÇhžhhŸh¶h K	ubh¸)”}”(hŒYThe bus driver that discovers the device uses this to register the
device with the core::”h]”hŒXThe bus driver that discovers the device uses this to register the
device with the core:”…””}”(hhØhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K
hhÇhžhubhŒliteral_block”“”)”}”(hŒ)int device_register(struct device * dev);”h]”hŒ)int device_register(struct device * dev);”…””}”hhèsbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1hæhŸh¶h KhhÇhžhubh¸)”}”(hŒ/The bus should initialize the following fields:”h]”hŒ/The bus should initialize the following fields:”…””}”(hhøhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÇhžhubhŒblock_quote”“”)”}”(hŒ- parent
- name
- bus_id
- bus
”h]”hŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒparent”h]”h¸)”}”(hj  h]”hŒparent”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  ubj  )”}”(hŒname”h]”h¸)”}”(hj,  h]”hŒname”…””}”(hj.  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj*  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  ubj  )”}”(hŒbus_id”h]”h¸)”}”(hjC  h]”hŒbus_id”…””}”(hjE  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjA  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  ubj  )”}”(hŒbus
”h]”h¸)”}”(hŒbus”h]”hŒbus”…””}”(hj\  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjX  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j  hŸh¶h Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hŸh¶h KhhÇhžhubh¸)”}”(hŒqA device is removed from the core when its reference count goes to
0. The reference count can be adjusted using::”h]”hŒpA device is removed from the core when its reference count goes to
0. The reference count can be adjusted using:”…””}”(hj~  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÇhžhubhç)”}”(hŒVstruct device * get_device(struct device * dev);
void put_device(struct device * dev);”h]”hŒVstruct device * get_device(struct device * dev);
void put_device(struct device * dev);”…””}”hjŒ  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KhhÇhžhubh¸)”}”(hŒ™get_device() will return a pointer to the struct device passed to it
if the reference is not already 0 (if it's in the process of being
removed already).”h]”hŒ›get_device() will return a pointer to the struct device passed to it
if the reference is not already 0 (if itâ€™s in the process of being
removed already).”…””}”(hjš  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhhÇhžhubh¸)”}”(hŒ<A driver can access the lock in the device structure using::”h]”hŒ;A driver can access the lock in the device structure using:”…””}”(hj¨  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K hhÇhžhubhç)”}”(hŒOvoid lock_device(struct device * dev);
void unlock_device(struct device * dev);”h]”hŒOvoid lock_device(struct device * dev);
void unlock_device(struct device * dev);”…””}”hj¶  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h K"hhÇhžhubeh}”(h]”Œprogramming-interface”ah ]”h"]”Œprogramming interface”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K	ubh¢)”}”(hhh]”(h§)”}”(hŒ
Attributes”h]”hŒ
Attributes”…””}”(hjÏ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjÌ  hžhhŸh¶h K'ubhç)”}”(hX,  struct device_attribute {
      struct attribute        attr;
      ssize_t (*show)(struct device *dev, struct device_attribute *attr,
                      char *buf);
      ssize_t (*store)(struct device *dev, struct device_attribute *attr,
                       const char *buf, size_t count);
};”h]”hX,  struct device_attribute {
      struct attribute        attr;
      ssize_t (*show)(struct device *dev, struct device_attribute *attr,
                      char *buf);
      ssize_t (*store)(struct device *dev, struct device_attribute *attr,
                       const char *buf, size_t count);
};”…””}”hjÝ  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h K+hjÌ  hžhubh¸)”}”(hŒGAttributes of devices can be exported by a device driver through sysfs.”h]”hŒGAttributes of devices can be exported by a device driver through sysfs.”…””}”(hjë  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K3hjÌ  hžhubh¸)”}”(hŒWPlease see Documentation/filesystems/sysfs.rst for more information
on how sysfs works.”h]”hŒWPlease see Documentation/filesystems/sysfs.rst for more information
on how sysfs works.”…””}”(hjù  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K5hjÌ  hžhubh¸)”}”(hŒ¾As explained in Documentation/core-api/kobject.rst, device attributes must be
created before the KOBJ_ADD uevent is generated. The only way to realize
that is by defining an attribute group.”h]”hŒ¾As explained in Documentation/core-api/kobject.rst, device attributes must be
created before the KOBJ_ADD uevent is generated. The only way to realize
that is by defining an attribute group.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K8hjÌ  hžhubh¸)”}”(hŒ:Attributes are declared using a macro called DEVICE_ATTR::”h]”hŒ9Attributes are declared using a macro called DEVICE_ATTR:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K<hjÌ  hžhubhç)”}”(hŒ)#define DEVICE_ATTR(name,mode,show,store)”h]”hŒ)#define DEVICE_ATTR(name,mode,show,store)”…””}”hj#  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h K>hjÌ  hžhubh¸)”}”(hŒ
Example:::”h]”hŒ	Example::”…””}”(hj1  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K@hjÌ  hžhubhç)”}”(hŒjstatic DEVICE_ATTR(type, 0444, type_show, NULL);
static DEVICE_ATTR(power, 0644, power_show, power_store);”h]”hŒjstatic DEVICE_ATTR(type, 0444, type_show, NULL);
static DEVICE_ATTR(power, 0644, power_show, power_store);”…””}”hj?  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KBhjÌ  hžhubh¸)”}”(hŒdHelper macros are available for common values of mode, so the above examples
can be simplified to:::”h]”hŒcHelper macros are available for common values of mode, so the above examples
can be simplified to::”…””}”(hjM  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KEhjÌ  hžhubhç)”}”(hŒ:static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RW(power);”h]”hŒ:static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RW(power);”…””}”hj[  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KHhjÌ  hžhubh¸)”}”(hŒ¸This declares two structures of type struct device_attribute with respective
names 'dev_attr_type' and 'dev_attr_power'. These two attributes can be
organized as follows into a group::”h]”hŒ¿This declares two structures of type struct device_attribute with respective
names â€˜dev_attr_typeâ€™ and â€˜dev_attr_powerâ€™. These two attributes can be
organized as follows into a group:”…””}”(hji  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KKhjÌ  hžhubhç)”}”(hX  static struct attribute *dev_attrs[] = {
      &dev_attr_type.attr,
      &dev_attr_power.attr,
      NULL,
};

static struct attribute_group dev_group = {
      .attrs = dev_attrs,
};

static const struct attribute_group *dev_groups[] = {
      &dev_group,
      NULL,
};”h]”hX  static struct attribute *dev_attrs[] = {
      &dev_attr_type.attr,
      &dev_attr_power.attr,
      NULL,
};

static struct attribute_group dev_group = {
      .attrs = dev_attrs,
};

static const struct attribute_group *dev_groups[] = {
      &dev_group,
      NULL,
};”…””}”hjw  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KOhjÌ  hžhubh¸)”}”(hŒwA helper macro is available for the common case of a single group, so the
above two structures can be declared using:::”h]”hŒvA helper macro is available for the common case of a single group, so the
above two structures can be declared using::”…””}”(hj…  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K^hjÌ  hžhubhç)”}”(hŒATTRIBUTE_GROUPS(dev);”h]”hŒATTRIBUTE_GROUPS(dev);”…””}”hj“  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KahjÌ  hžhubh¸)”}”(hŒThis array of groups can then be associated with a device by setting the
group pointer in struct device before device_register() is invoked::”h]”hŒŒThis array of groups can then be associated with a device by setting the
group pointer in struct device before device_register() is invoked:”…””}”(hj¡  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KchjÌ  hžhubhç)”}”(hŒ/dev->groups = dev_groups;
device_register(dev);”h]”hŒ/dev->groups = dev_groups;
device_register(dev);”…””}”hj¯  sbah}”(h]”h ]”h"]”h$]”h&]”höh÷uh1hæhŸh¶h KfhjÌ  hžhubh¸)”}”(hŒ¸The device_register() function will use the 'groups' pointer to create the
device attributes and the device_unregister() function will use this pointer
to remove the device attributes.”h]”hŒ¼The device_register() function will use the â€˜groupsâ€™ pointer to create the
device attributes and the device_unregister() function will use this pointer
to remove the device attributes.”…””}”(hj½  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KihjÌ  hžhubh¸)”}”(hXÖ  Word of warning:  While the kernel allows device_create_file() and
device_remove_file() to be called on a device at any time, userspace has
strict expectations on when attributes get created.  When a new device is
registered in the kernel, a uevent is generated to notify userspace (like
udev) that a new device is available.  If attributes are added after the
device is registered, then userspace won't get notified and userspace will
not know about the new attributes.”h]”hXØ  Word of warning:  While the kernel allows device_create_file() and
device_remove_file() to be called on a device at any time, userspace has
strict expectations on when attributes get created.  When a new device is
registered in the kernel, a uevent is generated to notify userspace (like
udev) that a new device is available.  If attributes are added after the
device is registered, then userspace wonâ€™t get notified and userspace will
not know about the new attributes.”…””}”(hjË  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KmhjÌ  hžhubh¸)”}”(hX  This is important for device driver that need to publish additional
attributes for a device at driver probe time.  If the device driver simply
calls device_create_file() on the device structure passed to it, then
userspace will never be notified of the new attributes.”h]”hX  This is important for device driver that need to publish additional
attributes for a device at driver probe time.  If the device driver simply
calls device_create_file() on the device structure passed to it, then
userspace will never be notified of the new attributes.”…””}”(hjÙ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KuhjÌ  hžhubeh}”(h]”Œ
attributes”ah ]”h"]”Œ
attributes”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K'ubeh}”(h]”Œthe-basic-device-structure”ah ]”h"]”Œthe basic device structure”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jô  jñ  jÉ  jÆ  jì  jé  uŒ	nametypes”}”(jô  ‰jÉ  ‰jì  ‰uh}”(jñ  h£jÆ  hÇjé  jÌ  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.