thunderbolt: Don't display nvm_version unless upgrade supported

The read will never succeed if NVM wasn't initialized due to an unknown
format.

Add a new callback for visibility to only show when supported.

Cc: stable@vger.kernel.org
Fixes: aef9c69 ("thunderbolt: Move vendor specific NVM handling into nvm.c")
Reported-by: Richard Hughes <hughsient@gmail.com>
Closes: fwupd/fwupd#8200
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Author: superm1

drivers/thunderbolt/retimer.c

@@ -103,6 +103,7 @@ static int tb_retimer_nvm_add(struct tb_retimer *rt)
 
 err_nvm:
 	dev_dbg(&rt->dev, "NVM upgrade disabled\n");
+	rt->no_nvm_upgrade = true;
 	if (!IS_ERR(nvm))
 		tb_nvm_free(nvm);
 
@@ -182,8 +183,6 @@ static ssize_t nvm_authenticate_show(struct device *dev,
 
 	if (!rt->nvm)
 		ret = -EAGAIN;
-	else if (rt->no_nvm_upgrade)
-		ret = -EOPNOTSUPP;
 	else
 		ret = sysfs_emit(buf, "%#x\n", rt->auth_status);
 
@@ -323,8 +322,6 @@ static ssize_t nvm_version_show(struct device *dev,
 
 	if (!rt->nvm)
 		ret = -EAGAIN;
-	else if (rt->no_nvm_upgrade)
-		ret = -EOPNOTSUPP;
 	else
 		ret = sysfs_emit(buf, "%x.%x\n", rt->nvm->major, rt->nvm->minor);
 
@@ -342,6 +339,19 @@ static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(vendor);
 
+static umode_t retimer_is_visible(struct kobject *kobj, struct attribute *attr,
+				  int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct tb_retimer *rt = tb_to_retimer(dev);
+
+	if (attr == &dev_attr_nvm_authenticate.attr ||
+	    attr == &dev_attr_nvm_version.attr)
+		return rt->no_nvm_upgrade ? 0 : attr->mode;
+
+	return attr->mode;
+}
+
 static struct attribute *retimer_attrs[] = {
 	&dev_attr_device.attr,
 	&dev_attr_nvm_authenticate.attr,
@@ -351,6 +361,7 @@ static struct attribute *retimer_attrs[] = {
 };
 
 static const struct attribute_group retimer_group = {
+	.is_visible = retimer_is_visible,
 	.attrs = retimer_attrs,
 };