/* * Sample kobject implementation * * Copyright (C) 2004-2007 Greg Kroah-Hartman * Copyright (C) 2007 Novell Inc. * * Released under the GPL version 2 only. * */ #include #include #include #include #include /* * This module shows how to create a simple subdirectory in sysfs called * /sys/kernel/kobject-example In that directory, 3 files are created: * "foo", "baz", and "bar". If an integer is written to these files, it can be * later read out of it. */ static int foo; static int baz; static int bar; /* * The "foo" file where a static variable is read from and written to. */ static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%d\n", foo); } static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int ret; ret = kstrtoint(buf, 10, &foo); if (ret < 0) return ret; return count; } /* Sysfs attributes cannot be world-writable. */ static struct kobj_attribute foo_attribute = __ATTR(foo, 0664, foo_show, foo_store); /* * More complex function where we determine which variable is being accessed by * looking at the attribute for the "baz" and "bar" files. */ static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { int var; if (strcmp(attr->attr.name, "baz") == 0) var = baz; else var = bar; return sprintf(buf, "%d\n", var); } static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int var, ret; ret = kstrtoint(buf, 10, &var); if (ret < 0) return ret; if (strcmp(attr->attr.name, "baz") == 0) baz = var; else bar = var; return count; } static struct kobj_attribute baz_attribute = __ATTR(baz, 0664, b_show, b_store); static struct kobj_attribute bar_attribute = __ATTR(bar, 0664, b_show, b_store); /* * Create a group of attributes so that we can create and destroy them all * at once. */ static struct attribute *attrs[] = { &foo_attribute.attr, &baz_attribute.attr, &bar_attribute.attr, NULL, /* need to NULL terminate the list of attributes */ }; /* * An unnamed attribute group will put all of the attributes directly in * the kobject directory. If we specify a name, a subdirectory will be * created for the attributes with the directory being the name of the * attribute group. */ static struct attribute_group attr_group = { .attrs = attrs, }; static struct kobject *example_kobj; static int __init example_init(void) { int retval; /* * Create a simple kobject with the name of "kobject_example", * located under /sys/kernel/ * * As this is a simple directory, no uevent will be sent to * userspace. That is why this function should not be used for * any type of dynamic kobjects, where the name and number are * not known ahead of time. */ example_kobj = kobject_create_and_add("kobject_example", kernel_kobj); if (!example_kobj) return -ENOMEM; /* Create the files associated with this kobject */ retval = sysfs_create_group(example_kobj, &attr_group); if (retval) kobject_put(example_kobj); return retval; } static void __exit example_exit(void) { kobject_put(example_kobj); } module_init(example_init); module_exit(example_exit); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Greg Kroah-Hartman "); lue='1'>ignoremode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 21:58:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 21:58:13 -0800
commite7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (patch)
treef63906f41699c8e38af9d12b063e2ceab0286ef2 /include/drm/drm_print.h
parente34bac726d27056081d0250c0e173e4b155aa340 (diff)
parent868c97a846a73e937d835b09b8c885a69df50ec8 (diff)
Merge tag 'docs-4.10' of git://git.lwn.net/linuxHEADmaster
Pull documentation update from Jonathan Corbet: "These are the documentation changes for 4.10. It's another busy cycle for the docs tree, as the sphinx conversion continues. Highlights include: - Further work on PDF output, which remains a bit of a pain but should be more solid now. - Five more DocBook template files converted to Sphinx. Only 27 to go... Lots of plain-text files have also been converted and integrated. - Images in binary formats have been replaced with more source-friendly versions. - Various bits of organizational work, including the renaming of various files discussed at the kernel summit. - New documentation for the device_link mechanism. ... and, of course, lots of typo fixes and small updates" * tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits) dma-buf: Extract dma-buf.rst Update Documentation/00-INDEX docs: 00-INDEX: document directories/files with no docs docs: 00-INDEX: remove non-existing entries docs: 00-INDEX: add missing entries for documentation files/dirs docs: 00-INDEX: consolidate process/ and admin-guide/ description scripts: add a script to check if Documentation/00-INDEX is sane Docs: change sh -> awk in REPORTING-BUGS Documentation/core-api/device_link: Add initial documentation core-api: remove an unexpected unident ppc/idle: Add documentation for powersave=off Doc: Correct typo, "Introdution" => "Introduction" Documentation/atomic_ops.txt: convert to ReST markup Documentation/local_ops.txt: convert to ReST markup Documentation/assoc_array.txt: convert to ReST markup docs-rst: parse-headers.pl: cleanup the documentation docs-rst: fix media cleandocs target docs-rst: media/Makefile: reorganize the rules docs-rst: media: build SVG from graphviz files docs-rst: replace bayer.png by a SVG image ...
Diffstat (limited to 'include/drm/drm_print.h')