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, 181 insertions, 0 deletions

diff --git a/drivers/base/isa.c b/drivers/base/isa.c
new file mode 100644
index 000000000..4e9f68080
--- /dev/null
+++ b/drivers/base/isa.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ISA bus.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/dma-mapping.h>
+#include <linux/isa.h>
+
+static struct device *isa_bus;
+
+struct isa_dev {
+	struct device dev;
+	struct device *next;
+	unsigned int id;
+};
+
+#define to_isa_dev(x) container_of((x), struct isa_dev, dev)
+
+static int isa_bus_match(struct device *dev, const struct device_driver *driver)
+{
+	struct isa_driver *isa_driver = to_isa_driver(driver);
+
+	if (dev->platform_data == isa_driver) {
+		if (!isa_driver->match ||
+			isa_driver->match(dev, to_isa_dev(dev)->id))
+			return 1;
+		dev->platform_data = NULL;
+	}
+	return 0;
+}
+
+static int isa_bus_probe(struct device *dev)
+{
+	struct isa_driver *isa_driver = dev->platform_data;
+
+	if (isa_driver && isa_driver->probe)
+		return isa_driver->probe(dev, to_isa_dev(dev)->id);
+
+	return 0;
+}
+
+static void isa_bus_remove(struct device *dev)
+{
+	struct isa_driver *isa_driver = dev->platform_data;
+
+	if (isa_driver && isa_driver->remove)
+		isa_driver->remove(dev, to_isa_dev(dev)->id);
+}
+
+static void isa_bus_shutdown(struct device *dev)
+{
+	struct isa_driver *isa_driver = dev->platform_data;
+
+	if (isa_driver && isa_driver->shutdown)
+		isa_driver->shutdown(dev, to_isa_dev(dev)->id);
+}
+
+static int isa_bus_suspend(struct device *dev, pm_message_t state)
+{
+	struct isa_driver *isa_driver = dev->platform_data;
+
+	if (isa_driver && isa_driver->suspend)
+		return isa_driver->suspend(dev, to_isa_dev(dev)->id, state);
+
+	return 0;
+}
+
+static int isa_bus_resume(struct device *dev)
+{
+	struct isa_driver *isa_driver = dev->platform_data;
+
+	if (isa_driver && isa_driver->resume)
+		return isa_driver->resume(dev, to_isa_dev(dev)->id);
+
+	return 0;
+}
+
+static const struct bus_type isa_bus_type = {
+	.name		= "isa",
+	.match		= isa_bus_match,
+	.probe		= isa_bus_probe,
+	.remove		= isa_bus_remove,
+	.shutdown	= isa_bus_shutdown,
+	.suspend	= isa_bus_suspend,
+	.resume		= isa_bus_resume
+};
+
+static void isa_dev_release(struct device *dev)
+{
+	kfree(to_isa_dev(dev));
+}
+
+void isa_unregister_driver(struct isa_driver *isa_driver)
+{
+	struct device *dev = isa_driver->devices;
+
+	while (dev) {
+		struct device *tmp = to_isa_dev(dev)->next;
+		device_unregister(dev);
+		dev = tmp;
+	}
+	driver_unregister(&isa_driver->driver);
+}
+EXPORT_SYMBOL_GPL(isa_unregister_driver);
+
+int isa_register_driver(struct isa_driver *isa_driver, unsigned int ndev)
+{
+	int error;
+	unsigned int id;
+
+	isa_driver->driver.bus	= &isa_bus_type;
+	isa_driver->devices	= NULL;
+
+	error = driver_register(&isa_driver->driver);
+	if (error)
+		return error;
+
+	for (id = 0; id < ndev; id++) {
+		struct isa_dev *isa_dev;
+
+		isa_dev = kzalloc_obj(*isa_dev);
+		if (!isa_dev) {
+			error = -ENOMEM;
+			break;
+		}
+
+		isa_dev->dev.parent	= isa_bus;
+		isa_dev->dev.bus	= &isa_bus_type;
+
+		dev_set_name(&isa_dev->dev, "%s.%u",
+			     isa_driver->driver.name, id);
+		isa_dev->dev.platform_data	= isa_driver;
+		isa_dev->dev.release		= isa_dev_release;
+		isa_dev->id			= id;
+
+		isa_dev->dev.coherent_dma_mask = DMA_BIT_MASK(24);
+		isa_dev->dev.dma_mask = &isa_dev->dev.coherent_dma_mask;
+
+		error = device_register(&isa_dev->dev);
+		if (error) {
+			put_device(&isa_dev->dev);
+			break;
+		}
+
+		isa_dev->next = isa_driver->devices;
+		isa_driver->devices = &isa_dev->dev;
+	}
+
+	if (!error && !isa_driver->devices)
+		error = -ENODEV;
+
+	if (error)
+		isa_unregister_driver(isa_driver);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(isa_register_driver);
+
+static int __init isa_bus_init(void)
+{
+	int error;
+
+	error = bus_register(&isa_bus_type);
+	if (error)
+		return error;
+
+	isa_bus = root_device_register("isa");
+	if (IS_ERR(isa_bus)) {
+		bus_unregister(&isa_bus_type);
+		return PTR_ERR(isa_bus);
+	}
+
+	return 0;
+}
+
+postcore_initcall(isa_bus_init);