iio: proximity: isl29501: Fix return type of isl29501_register_writegrafted

isl29501_register_write() was returning a u32 instead of an int.
Since the function returns negative error codes (such as -ERANGE or
return values from i2c_smbus_write_byte_data()), returning an unsigned
integer type prevents callers from correctly checking for negative error
conditions.

Fix this by changing the function return type from u32 to int.

This was found through manual code review.

Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 201 insertions, 0 deletions

diff --git a/lib/kunit/device.c b/lib/kunit/device.c
new file mode 100644
index 000000000..85d57ad34
--- /dev/null
+++ b/lib/kunit/device.c
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit-managed device implementation
+ *
+ * Implementation of struct kunit_device helpers for fake devices whose
+ * lifecycle is managed by KUnit.
+ *
+ * Copyright (C) 2023, Google LLC.
+ * Author: David Gow <davidgow@google.com>
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+
+#include <kunit/test.h>
+#include <kunit/device.h>
+#include <kunit/resource.h>
+
+#include "device-impl.h"
+
+/* Wrappers for use with kunit_add_action() */
+KUNIT_DEFINE_ACTION_WRAPPER(device_unregister_wrapper, device_unregister, struct device *);
+KUNIT_DEFINE_ACTION_WRAPPER(driver_unregister_wrapper, driver_unregister, struct device_driver *);
+
+/* The root device for the KUnit bus, parent of all kunit_devices. */
+static struct device *kunit_bus_device;
+
+/* A device owned by a KUnit test. */
+struct kunit_device {
+	struct device dev;
+	/* The KUnit test which owns this device. */
+	struct kunit *owner;
+	/* If the driver is managed by KUnit and unique to this device. */
+	const struct device_driver *driver;
+};
+
+#define to_kunit_device(d) container_of_const(d, struct kunit_device, dev)
+
+static const struct bus_type kunit_bus_type = {
+	.name		= "kunit",
+};
+
+/* Register the 'kunit_bus' used for fake devices. */
+int kunit_bus_init(void)
+{
+	int error;
+
+	kunit_bus_device = root_device_register("kunit");
+	if (IS_ERR(kunit_bus_device))
+		return PTR_ERR(kunit_bus_device);
+
+	error = bus_register(&kunit_bus_type);
+	if (error)
+		root_device_unregister(kunit_bus_device);
+	return error;
+}
+
+/* Unregister the 'kunit_bus' in case the KUnit module is unloaded. */
+void kunit_bus_shutdown(void)
+{
+	/* Make sure the bus exists before we unregister it. */
+	if (IS_ERR_OR_NULL(kunit_bus_device))
+		return;
+
+	bus_unregister(&kunit_bus_type);
+
+	root_device_unregister(kunit_bus_device);
+
+	kunit_bus_device = NULL;
+}
+
+/* Release a 'fake' KUnit device. */
+static void kunit_device_release(struct device *d)
+{
+	kfree(to_kunit_device(d));
+}
+
+/*
+ * Create and register a KUnit-managed struct device_driver on the kunit_bus.
+ * Returns an error pointer on failure.
+ */
+struct device_driver *kunit_driver_create(struct kunit *test, const char *name)
+{
+	struct device_driver *driver;
+	int err = -ENOMEM;
+
+	driver = kunit_kzalloc(test, sizeof(*driver), GFP_KERNEL);
+
+	if (!driver)
+		return ERR_PTR(err);
+
+	driver->name = kunit_kstrdup_const(test, name, GFP_KERNEL);
+	driver->bus = &kunit_bus_type;
+	driver->owner = THIS_MODULE;
+
+	err = driver_register(driver);
+	if (err) {
+		kunit_kfree(test, driver);
+		return ERR_PTR(err);
+	}
+
+	kunit_add_action(test, driver_unregister_wrapper, driver);
+	return driver;
+}
+EXPORT_SYMBOL_GPL(kunit_driver_create);
+
+/* Helper which creates a kunit_device, attaches it to the kunit_bus*/
+static struct kunit_device *kunit_device_register_internal(struct kunit *test,
+							   const char *name)
+{
+	struct kunit_device *kunit_dev;
+	int err = -ENOMEM;
+
+	kunit_dev = kzalloc_obj(*kunit_dev);
+	if (!kunit_dev)
+		return ERR_PTR(err);
+
+	kunit_dev->owner = test;
+
+	err = dev_set_name(&kunit_dev->dev, "%s.%s", test->name, name);
+	if (err) {
+		kfree(kunit_dev);
+		return ERR_PTR(err);
+	}
+
+	kunit_dev->dev.release = kunit_device_release;
+	kunit_dev->dev.bus = &kunit_bus_type;
+	kunit_dev->dev.parent = kunit_bus_device;
+
+	err = device_register(&kunit_dev->dev);
+	if (err) {
+		put_device(&kunit_dev->dev);
+		return ERR_PTR(err);
+	}
+
+	kunit_dev->dev.dma_mask = &kunit_dev->dev.coherent_dma_mask;
+	kunit_dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+
+	kunit_add_action(test, device_unregister_wrapper, &kunit_dev->dev);
+
+	return kunit_dev;
+}
+
+/*
+ * Create and register a new KUnit-managed device, using the user-supplied device_driver.
+ * On failure, returns an error pointer.
+ */
+struct device *kunit_device_register_with_driver(struct kunit *test,
+						 const char *name,
+						 const struct device_driver *drv)
+{
+	struct kunit_device *kunit_dev = kunit_device_register_internal(test, name);
+
+	if (IS_ERR_OR_NULL(kunit_dev))
+		return ERR_CAST(kunit_dev);
+
+	return &kunit_dev->dev;
+}
+EXPORT_SYMBOL_GPL(kunit_device_register_with_driver);
+
+/*
+ * Create and register a new KUnit-managed device, including a matching device_driver.
+ * On failure, returns an error pointer.
+ */
+struct device *kunit_device_register(struct kunit *test, const char *name)
+{
+	struct device_driver *drv;
+	struct kunit_device *dev;
+
+	drv = kunit_driver_create(test, name);
+	if (IS_ERR(drv))
+		return ERR_CAST(drv);
+
+	dev = kunit_device_register_internal(test, name);
+	if (IS_ERR(dev)) {
+		kunit_release_action(test, driver_unregister_wrapper, (void *)drv);
+		return ERR_CAST(dev);
+	}
+
+	/* Request the driver be freed. */
+	dev->driver = drv;
+
+
+	return &dev->dev;
+}
+EXPORT_SYMBOL_GPL(kunit_device_register);
+
+/* Unregisters a KUnit-managed device early (including the driver, if automatically created). */
+void kunit_device_unregister(struct kunit *test, struct device *dev)
+{
+	const struct device_driver *driver = to_kunit_device(dev)->driver;
+
+	kunit_release_action(test, device_unregister_wrapper, dev);
+	if (driver) {
+		const char *driver_name = driver->name;
+		kunit_release_action(test, driver_unregister_wrapper, (void *)driver);
+		kunit_kfree_const(test, driver_name);
+	}
+}
+EXPORT_SYMBOL_GPL(kunit_device_unregister);
+