[PATCH 0/2] gpio: add kunit tests for GPIO core

[PATCH 0/2] gpio: add kunit tests for GPIO core

[Bartosz Golaszewski]

This series adds a first batch of kunit tests for GPIO core. I intend to
gradually add more coverage for functionalities that can't really be
tested from user-space with the existing kernel selftests or libgpiod
tests.

Merging strategy: with an Ack from kunit maintainers, this can go
through the GPIO tree for v7.2.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
Bartosz Golaszewski (2):
      kunit: provide kunit_platform_device_register_full()
      gpio: add kunit test cases for the GPIO subsystem

 drivers/gpio/Kconfig            |   8 +
 drivers/gpio/Makefile           |   1 +
 drivers/gpio/gpiolib-kunit.c    | 354 ++++++++++++++++++++++++++++++++++++++++
 include/kunit/platform_device.h |   4 +
 lib/kunit/platform.c            |  31 ++++
 5 files changed, 398 insertions(+)
---
base-commit: 4a1989fb6514ca2a4b157ff4700bdcc8bdd9a978
change-id: 20260326-gpiolib-kunit-d7f1b5541ffa

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

[PATCH 1/2] kunit: provide kunit_platform_device_register_full()

[Bartosz Golaszewski]

Provide a kunit-managed variant of platform_device_register_full().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
 include/kunit/platform_device.h |  4 ++++
 lib/kunit/platform.c            | 31 +++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/kunit/platform_device.h b/include/kunit/platform_device.h
index f8236a8536f7ebcee6b0e00a7bd799a14b345c1b..8cad6e1c3e7efba862862b579089f2f317784a73 100644
--- a/include/kunit/platform_device.h
+++ b/include/kunit/platform_device.h
@@ -6,10 +6,14 @@ struct completion;
 struct kunit;
 struct platform_device;
 struct platform_driver;
+struct platform_device_info;
 
 struct platform_device *
 kunit_platform_device_alloc(struct kunit *test, const char *name, int id);
 int kunit_platform_device_add(struct kunit *test, struct platform_device *pdev);
+struct platform_device *
+kunit_platform_device_register_full(struct kunit *test,
+				    const struct platform_device_info *pdevinfo);
 
 int kunit_platform_device_prepare_wait_for_probe(struct kunit *test,
 						 struct platform_device *pdev,
diff --git a/lib/kunit/platform.c b/lib/kunit/platform.c
index 0b518de26065d65dac3bd49dd94a4b3e7ea0634b..583b50b538c79599ebbf33e261fe2e9ced35efa9 100644
--- a/lib/kunit/platform.c
+++ b/lib/kunit/platform.c
@@ -6,6 +6,7 @@
 #include <linux/completion.h>
 #include <linux/device/bus.h>
 #include <linux/device/driver.h>
+#include <linux/err.h>
 #include <linux/platform_device.h>
 
 #include <kunit/platform_device.h>
@@ -130,6 +131,36 @@ int kunit_platform_device_add(struct kunit *test, struct platform_device *pdev)
 }
 EXPORT_SYMBOL_GPL(kunit_platform_device_add);
 
+/**
+ * kunit_platform_device_register_full() - Register a KUnit test-managed platform
+ *                                         device described by platform device info
+ * @test: test context
+ * @pdevinfo: platform device information describing the new device
+ *
+ * Register a test-managed platform device. The device is unregistered when the
+ * test completes.
+ *
+ * Return: New platform device on success, IS_ERR() on error.
+ */
+struct platform_device *
+kunit_platform_device_register_full(struct kunit *test,
+				    const struct platform_device_info *pdevinfo)
+{
+	struct platform_device *pdev;
+	int ret;
+
+	pdev = platform_device_register_full(pdevinfo);
+	if (IS_ERR(pdev))
+		return pdev;
+
+	ret = kunit_add_action_or_reset(test, platform_device_unregister_wrapper, pdev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return pdev;
+}
+EXPORT_SYMBOL_GPL(kunit_platform_device_register_full);
+
 struct kunit_platform_device_probe_nb {
 	struct completion *x;
 	struct device *dev;

-- 
2.47.3

[PATCH 2/2] gpio: add kunit test cases for the GPIO subsystem

[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