* [PATCH 2/2] gpio: add kunit test cases for the GPIO subsystem
2026-05-18 14:16 [PATCH 0/2] gpio: add kunit tests for GPIO core Bartosz Golaszewski
2026-05-18 14:16 ` [PATCH 1/2] kunit: provide kunit_platform_device_register_full() Bartosz Golaszewski
@ 2026-05-18 14:16 ` Bartosz Golaszewski
1 sibling, 0 replies; 3+ messages in thread
From: Bartosz Golaszewski @ 2026-05-18 14:16 UTC (permalink / raw)
To: Brendan Higgins, David Gow, Rae Moar, Linus Walleij, Bartosz Golaszewski
Cc: linux-kselftest, kunit-dev, linux-kernel, linux-gpio,
Bartosz Golaszewski
Add a module containing kunit test cases for GPIO core. The idea is to
use it to test functionalities that can't easily be tested from
user-space with kernel selftests or GPIO character device test suites
provided by the libgpiod package.
For now add test cases that verify software node based lookup and ensure
that a GPIO provider unbinding with active consumers does not cause a
crash.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
drivers/gpio/Kconfig | 8 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpiolib-kunit.c | 354 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 363 insertions(+)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 020e51e30317a8574638bbe31365a3cf49591641..2ed9ba8d9c12b0fec9f6fa3fe6077f5588bf719c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -102,6 +102,14 @@ config GPIO_CDEV_V1
This ABI version is deprecated.
Please use the latest ABI for new developments.
+config GPIO_KUNIT
+ tristate "Build GPIO Kunit test cases"
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Say Y here to build the module containing Kunit test cases verifying
+ the functionality of the GPIO subsystem.
+
config GPIO_GENERIC
depends on HAS_IOMEM # Only for IOMEM drivers
tristate
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index b267598b517de089cf6339d837264f1d09e275c0..b01163c6a94db1aa21d895fb897e87be62b816e4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_GPIO_ACPI) += gpiolib-acpi.o
gpiolib-acpi-y := gpiolib-acpi-core.o gpiolib-acpi-quirks.o
obj-$(CONFIG_GPIOLIB) += gpiolib-swnode.o
obj-$(CONFIG_GPIO_SHARED) += gpiolib-shared.o
+obj-$(CONFIG_GPIO_KUNIT) += gpiolib-kunit.o
# Device drivers. Generally keep list sorted alphabetically
obj-$(CONFIG_GPIO_REGMAP) += gpio-regmap.o
diff --git a/drivers/gpio/gpiolib-kunit.c b/drivers/gpio/gpiolib-kunit.c
new file mode 100644
index 0000000000000000000000000000000000000000..f45ba72362f82387d7e345fe57c6ae976265ff9c
--- /dev/null
+++ b/drivers/gpio/gpiolib-kunit.c
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) Qualcomm Technologies, Inc. and/or its subsidiaries
+ */
+
+#include <linux/fwnode.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
+#include <linux/gpio/property.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#include <kunit/platform_device.h>
+#include <kunit/test.h>
+
+#define GPIO_TEST_PROVIDER "gpio-test-provider"
+#define GPIO_SWNODE_TEST_CONSUMER "gpio-swnode-test-consumer"
+#define GPIO_UNBIND_TEST_CONSUMER "gpio-unbind-test-consumer"
+
+static int gpio_test_provider_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int gpio_test_provider_set(struct gpio_chip *gc, unsigned int offset, int value)
+{
+ return 0;
+}
+
+static int gpio_test_provider_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct gpio_chip *gc;
+
+ gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
+ if (!gc)
+ return -ENOMEM;
+
+ gc->base = -1;
+ gc->ngpio = 4;
+ gc->label = "gpio-swnode-consumer-test-device";
+ gc->parent = dev;
+ gc->owner = THIS_MODULE;
+
+ gc->get_direction = gpio_test_provider_get_direction;
+ gc->set = gpio_test_provider_set;
+
+ return devm_gpiochip_add_data(dev, gc, NULL);
+}
+
+static struct platform_driver gpio_test_provider_driver = {
+ .probe = gpio_test_provider_probe,
+ .driver = {
+ .name = GPIO_TEST_PROVIDER,
+ },
+};
+
+static const struct software_node gpio_test_provider_swnode = {
+ .name = "gpio-test-provider-primary",
+};
+
+struct gpio_swnode_consumer_pdata {
+ bool gpio_ok;
+};
+
+static const struct gpio_swnode_consumer_pdata gpio_swnode_pdata_template = {
+ .gpio_ok = false,
+};
+
+static int gpio_swnode_consumer_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct gpio_swnode_consumer_pdata *pdata = dev_get_platdata(dev);
+ struct gpio_desc *desc;
+
+ desc = devm_gpiod_get(dev, "foo", GPIOD_OUT_HIGH);
+ if (IS_ERR(desc))
+ return PTR_ERR(desc);
+
+ pdata->gpio_ok = true;
+
+ return 0;
+}
+
+static struct platform_driver gpio_swnode_consumer_driver = {
+ .probe = gpio_swnode_consumer_probe,
+ .driver = {
+ .name = GPIO_SWNODE_TEST_CONSUMER,
+ },
+};
+
+static void gpio_swnode_lookup_by_primary(struct kunit *test)
+{
+ struct gpio_swnode_consumer_pdata *pdata;
+ struct platform_device_info pdevinfo;
+ struct property_entry properties[2];
+ struct platform_device *pdev;
+ int ret;
+
+ ret = kunit_platform_driver_register(test, &gpio_test_provider_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ ret = kunit_platform_driver_register(test, &gpio_swnode_consumer_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_TEST_PROVIDER,
+ .id = PLATFORM_DEVID_NONE,
+ .swnode = &gpio_test_provider_swnode,
+ };
+
+ pdev = kunit_platform_device_register_full(test, &pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ properties[0] = PROPERTY_ENTRY_GPIO("foo-gpios",
+ &gpio_test_provider_swnode,
+ 0, GPIO_ACTIVE_HIGH);
+ properties[1] = (struct property_entry){ };
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_SWNODE_TEST_CONSUMER,
+ .id = PLATFORM_DEVID_NONE,
+ .data = &gpio_swnode_pdata_template,
+ .size_data = sizeof(gpio_swnode_pdata_template),
+ .properties = properties,
+ };
+
+ pdev = kunit_platform_device_register_full(test, &pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ wait_for_device_probe();
+ scoped_guard(device, &pdev->dev)
+ KUNIT_ASSERT_TRUE(test, device_is_bound(&pdev->dev));
+
+ pdata = dev_get_platdata(&pdev->dev);
+ KUNIT_ASSERT_TRUE(test, pdata->gpio_ok);
+}
+
+static void gpio_swnode_lookup_by_secondary(struct kunit *test)
+{
+ struct gpio_swnode_consumer_pdata *pdata;
+ struct platform_device_info pdevinfo;
+ struct property_entry properties[2];
+ struct fwnode_handle *primary;
+ struct platform_device *pdev;
+ int ret;
+
+ /*
+ * Can't live on the stack as it will still get referenced in cleanup
+ * path after this function returns.
+ */
+ primary = kunit_kzalloc(test, sizeof(*primary), GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, primary);
+
+ ret = kunit_platform_driver_register(test, &gpio_test_provider_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ ret = kunit_platform_driver_register(test, &gpio_swnode_consumer_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ fwnode_init(primary, NULL);
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_TEST_PROVIDER,
+ .id = PLATFORM_DEVID_NONE,
+ .fwnode = primary,
+ .swnode = &gpio_test_provider_swnode,
+ };
+
+ pdev = kunit_platform_device_register_full(test, &pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ properties[0] = PROPERTY_ENTRY_GPIO("foo-gpios",
+ &gpio_test_provider_swnode,
+ 0, GPIO_ACTIVE_HIGH);
+ properties[1] = (struct property_entry){ };
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_SWNODE_TEST_CONSUMER,
+ .id = PLATFORM_DEVID_NONE,
+ .data = &gpio_swnode_pdata_template,
+ .size_data = sizeof(gpio_swnode_pdata_template),
+ .properties = properties,
+ };
+
+ pdev = kunit_platform_device_register_full(test, &pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
+
+ wait_for_device_probe();
+ scoped_guard(device, &pdev->dev)
+ KUNIT_ASSERT_TRUE(test, device_is_bound(&pdev->dev));
+
+ pdata = dev_get_platdata(&pdev->dev);
+ KUNIT_ASSERT_TRUE(test, pdata->gpio_ok);
+}
+
+static struct kunit_case gpio_swnode_lookup_tests[] = {
+ KUNIT_CASE(gpio_swnode_lookup_by_primary),
+ KUNIT_CASE(gpio_swnode_lookup_by_secondary),
+ { }
+};
+
+static struct kunit_suite gpio_swnode_lookup_test_suite = {
+ .name = "gpio-swnode-lookup",
+ .test_cases = gpio_swnode_lookup_tests,
+};
+
+static BLOCKING_NOTIFIER_HEAD(gpio_unbind_notifier);
+
+struct gpio_unbind_consumer_drvdata {
+ struct device *dev;
+ struct gpio_desc *desc;
+ struct notifier_block nb;
+ int set_retval;
+};
+
+static int gpio_unbind_notify(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct gpio_unbind_consumer_drvdata *drvdata =
+ container_of(nb, struct gpio_unbind_consumer_drvdata, nb);
+ struct device *dev = data;
+
+ if (dev != drvdata->dev)
+ return NOTIFY_DONE;
+
+ drvdata->set_retval = gpiod_set_value_cansleep(drvdata->desc, 0);
+
+ return NOTIFY_OK;
+}
+
+static void gpio_unbind_unregister_notifier(void *data)
+{
+ struct notifier_block *nb = data;
+
+ blocking_notifier_chain_unregister(&gpio_unbind_notifier, nb);
+}
+
+static int gpio_unbind_consumer_probe(struct platform_device *pdev)
+{
+ struct gpio_unbind_consumer_drvdata *data;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->dev = dev;
+
+ data->desc = devm_gpiod_get(dev, "foo", GPIOD_OUT_HIGH);
+ if (IS_ERR(data->desc))
+ return PTR_ERR(data->desc);
+
+ data->nb.notifier_call = gpio_unbind_notify;
+ ret = blocking_notifier_chain_register(&gpio_unbind_notifier, &data->nb);
+ if (ret)
+ return ret;
+
+ ret = devm_add_action_or_reset(dev, gpio_unbind_unregister_notifier, &data->nb);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, data);
+
+ return 0;
+}
+
+static struct platform_driver gpio_unbind_consumer_driver = {
+ .probe = gpio_unbind_consumer_probe,
+ .driver = {
+ .name = GPIO_UNBIND_TEST_CONSUMER,
+ },
+};
+
+static void gpio_unbind_with_consumers(struct kunit *test)
+{
+ struct gpio_unbind_consumer_drvdata *cons_data;
+ struct platform_device_info pdevinfo;
+ struct property_entry properties[2];
+ struct platform_device *prvd, *cons;
+ int ret;
+
+ ret = kunit_platform_driver_register(test, &gpio_test_provider_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ ret = kunit_platform_driver_register(test, &gpio_unbind_consumer_driver);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_TEST_PROVIDER,
+ .id = PLATFORM_DEVID_NONE,
+ .swnode = &gpio_test_provider_swnode,
+ };
+
+ prvd = platform_device_register_full(&pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, prvd);
+
+ properties[0] = PROPERTY_ENTRY_GPIO("foo-gpios",
+ &gpio_test_provider_swnode,
+ 0, GPIO_ACTIVE_HIGH);
+ properties[1] = (struct property_entry){ };
+
+ pdevinfo = (struct platform_device_info){
+ .name = GPIO_UNBIND_TEST_CONSUMER,
+ .id = PLATFORM_DEVID_NONE,
+ .properties = properties,
+ };
+
+ cons = kunit_platform_device_register_full(test, &pdevinfo);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cons);
+
+ wait_for_device_probe();
+ scoped_guard(device, &cons->dev)
+ KUNIT_ASSERT_TRUE(test, device_is_bound(&cons->dev));
+
+ platform_device_unregister(prvd);
+
+ ret = blocking_notifier_call_chain(&gpio_unbind_notifier, 0, &cons->dev);
+ KUNIT_ASSERT_EQ(test, ret, NOTIFY_OK);
+
+ scoped_guard(device, &cons->dev) {
+ cons_data = platform_get_drvdata(cons);
+ /*
+ * We can't have KUNIT_ASSERT_EQ() under the guard. Despite
+ * the lock being released automatically, it will complain that
+ * a lock is still taken during a test abort.
+ */
+ ret = cons_data->set_retval;
+ }
+
+ KUNIT_ASSERT_EQ(test, cons_data->set_retval, -ENODEV);
+}
+
+static struct kunit_case gpio_unbind_with_consumers_tests[] = {
+ KUNIT_CASE(gpio_unbind_with_consumers),
+ { }
+};
+
+static struct kunit_suite gpio_unbind_with_consumers_test_suite = {
+ .name = "gpio-unbind-with-consumers",
+ .test_cases = gpio_unbind_with_consumers_tests,
+};
+
+kunit_test_suites(
+ &gpio_swnode_lookup_test_suite,
+ &gpio_unbind_with_consumers_test_suite,
+);
+
+MODULE_DESCRIPTION("Test module for the GPIO subsystem");
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>");
+MODULE_LICENSE("GPL");
--
2.47.3
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