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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /samples/kobject/kobject-example.c
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Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
Diffstat (limited to 'samples/kobject/kobject-example.c')
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diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c
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+// 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>");