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, 99 insertions, 0 deletions

diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c
new file mode 100644
index 000000000..954c3412d
--- /dev/null
+++ b/lib/notifier-error-inject.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/module.h>
+
+#include "notifier-error-inject.h"
+
+static int debugfs_errno_set(void *data, u64 val)
+{
+	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
+	return 0;
+}
+
+static int debugfs_errno_get(void *data, u64 *val)
+{
+	*val = *(int *)data;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set,
+			"%lld\n");
+
+static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
+				struct dentry *parent, int *value)
+{
+	return debugfs_create_file(name, mode, parent, value, &fops_errno);
+}
+
+static int notifier_err_inject_callback(struct notifier_block *nb,
+				unsigned long val, void *p)
+{
+	int err = 0;
+	struct notifier_err_inject *err_inject =
+		container_of(nb, struct notifier_err_inject, nb);
+	struct notifier_err_inject_action *action;
+
+	for (action = err_inject->actions; action->name; action++) {
+		if (action->val == val) {
+			err = action->error;
+			break;
+		}
+	}
+	if (err)
+		pr_info("Injecting error (%d) to %s\n", err, action->name);
+
+	return notifier_from_errno(err);
+}
+
+struct dentry *notifier_err_inject_dir;
+EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
+
+struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
+			struct notifier_err_inject *err_inject, int priority)
+{
+	struct notifier_err_inject_action *action;
+	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+	struct dentry *dir;
+	struct dentry *actions_dir;
+
+	err_inject->nb.notifier_call = notifier_err_inject_callback;
+	err_inject->nb.priority = priority;
+
+	dir = debugfs_create_dir(name, parent);
+
+	actions_dir = debugfs_create_dir("actions", dir);
+
+	for (action = err_inject->actions; action->name; action++) {
+		struct dentry *action_dir;
+
+		action_dir = debugfs_create_dir(action->name, actions_dir);
+
+		/*
+		 * Create debugfs r/w file containing action->error. If
+		 * notifier call chain is called with action->val, it will
+		 * fail with the error code
+		 */
+		debugfs_create_errno("error", mode, action_dir, &action->error);
+	}
+	return dir;
+}
+EXPORT_SYMBOL_GPL(notifier_err_inject_init);
+
+static int __init err_inject_init(void)
+{
+	notifier_err_inject_dir =
+		debugfs_create_dir("notifier-error-inject", NULL);
+
+	return 0;
+}
+
+static void __exit err_inject_exit(void)
+{
+	debugfs_remove_recursive(notifier_err_inject_dir);
+}
+
+module_init(err_inject_init);
+module_exit(err_inject_exit);
+
+MODULE_DESCRIPTION("Notifier error injection module");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");