tee: add tee_device_set_dev_groups()

Add tee_device_set_dev_groups() to TEE drivers to supply driver specific
attribute groups. The class specific attributes are from now on added
via the tee_class, which currently only consist of implementation_id.

Signed-off-by: Jens Wiklander <[e-mail]>
Reviewed-by: Sumit Garg <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/tee/tee_core.c

···
 static DECLARE_BITMAP(dev_mask, TEE_NUM_DEVICES);
 static DEFINE_SPINLOCK(driver_lock);
 
-static const struct class tee_class = {
-	.name = "tee",
-};
-
+static const struct class tee_class;
 static dev_t tee_devt;
 
 struct tee_context *teedev_open(struct tee_device *teedev)
···
 }
 EXPORT_SYMBOL_GPL(tee_device_alloc);
 
+void tee_device_set_dev_groups(struct tee_device *teedev,
+			       const struct attribute_group **dev_groups)
+{
+	teedev->dev.groups = dev_groups;
+}
+EXPORT_SYMBOL_GPL(tee_device_set_dev_groups);
+
 static ssize_t implementation_id_show(struct device *dev,
 				      struct device_attribute *attr, char *buf)
 {
···
 
 ATTRIBUTE_GROUPS(tee_dev);
 
+static const struct class tee_class = {
+	.name = "tee",
+	.dev_groups = tee_dev_groups,
+};
+
 /**
  * tee_device_register() - Registers a TEE device
  * @teedev:	Device to register
···
 		dev_err(&teedev->dev, "attempt to register twice\n");
 		return -EINVAL;
 	}
-
-	teedev->dev.groups = tee_dev_groups;
 
 	rc = cdev_device_add(&teedev->cdev, &teedev->dev);
 	if (rc) {

include/linux/tee_core.h

···
 void tee_device_unregister(struct tee_device *teedev);
 
 /**
+ * tee_device_set_dev_groups() - Set device attribute groups
+ * @teedev:	Device to register
+ * @dev_groups: Attribute groups
+ *
+ * Assigns the provided @dev_groups to the @teedev to be registered later
+ * with tee_device_register(). Calling this function is optional, but if
+ * it's called it must be called before tee_device_register().
+ */
+void tee_device_set_dev_groups(struct tee_device *teedev,
+			       const struct attribute_group **dev_groups);
+
+/**
  * tee_session_calc_client_uuid() - Calculates client UUID for session
  * @uuid:		Resulting UUID
  * @connection_method:	Connection method for session (TEE_IOCTL_LOGIN_*)