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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /samples/kobject/kobject-example.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'samples/kobject/kobject-example.c')
| -rw-r--r-- | samples/kobject/kobject-example.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c new file mode 100644 index 000000000..36f3fbc47 --- /dev/null +++ b/samples/kobject/kobject-example.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Sample kobject implementation + * + * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2007 Novell Inc. + */ +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/module.h> +#include <linux/init.h> + +/* + * 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, const struct kobj_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%d\n", foo); +} + +static ssize_t foo_store(struct kobject *kobj, const 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 const struct kobj_attribute foo_attribute = + __KOBJ_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, const struct kobj_attribute *attr, + char *buf) +{ + int var; + + if (strcmp(attr->attr.name, "baz") == 0) + var = baz; + else + var = bar; + return sysfs_emit(buf, "%d\n", var); +} + +static ssize_t b_store(struct kobject *kobj, const 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 const struct kobj_attribute baz_attribute = + __KOBJ_ATTR(baz, 0664, b_show, b_store); +static const struct kobj_attribute bar_attribute = + __KOBJ_ATTR(bar, 0664, b_show, b_store); + + +/* + * Create a group of attributes so that we can create and destroy them all + * at once. + */ +static const struct attribute *const 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 const struct attribute_group attr_group = { + .attrs_const = 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_DESCRIPTION("Sample kobject implementation"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>"); |
