From: Mario Limonciello <mario.limonciello@amd.com>

Some drivers have static information that can be useful for userspace to
have, but maintaining a sysfs file is overkill. Add an optional callback
for drivers to be able to add their own uevent variables.

Cc: Richard Hughes <hughsient@gmail.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/hid/hid-core.c | 6 ++++++
 include/linux/hid.h    | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 1b18e0dadbac..de95470066d9 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2844,6 +2844,12 @@ static int hid_uevent(const struct device *dev, struct kobj_uevent_env *env)
 				   hdev->firmware_version))
 			return -ENOMEM;
 	}
+	if (hdev->uevent) {
+		int ret = hdev->uevent(dev, env);
+
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
diff --git a/include/linux/hid.h b/include/linux/hid.h
index ffc81a8c7a49..36e3c167c7ff 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -680,6 +680,7 @@ struct hid_device {
 	void (*hiddev_hid_event) (struct hid_device *, struct hid_field *field,
 				  struct hid_usage *, __s32);
 	void (*hiddev_report_event) (struct hid_device *, struct hid_report *);
+	int (*uevent)(const struct device *dev, struct kobj_uevent_env *env);
 
 	/* debugging support via debugfs */
 	unsigned short debug;
-- 
2.50.0