vfio: platform: add compat in vfio_platform_device

Let's retrieve the compatibility string on probe and store it
in the vfio_platform_device struct
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/platform/vfio_platform_common.c

@@ -41,16 +41,11 @@ static const struct vfio_platform_reset_combo reset_lookup_table[] = {
 static void vfio_platform_get_reset(struct vfio_platform_device *vdev,
 				    struct device *dev)
 {
-	const char *compat;
 	int (*reset)(struct vfio_platform_device *);
-	int ret, i;
-
-	ret = device_property_read_string(dev, "compatible", &compat);
-	if (ret)
-		return;
+	int i;
 
 	for (i = 0 ; i < ARRAY_SIZE(reset_lookup_table); i++) {
-		if (!strcmp(reset_lookup_table[i].compat, compat)) {
+		if (!strcmp(reset_lookup_table[i].compat, vdev->compat)) {
 			request_module(reset_lookup_table[i].module_name);
 			reset = __symbol_get(
 				reset_lookup_table[i].reset_function_name);
@@ -544,6 +539,12 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	if (!vdev)
 		return -EINVAL;
 
+	ret = device_property_read_string(dev, "compatible", &vdev->compat);
+	if (ret) {
+		pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name);
+		return -EINVAL;
+	}
+
 	group = iommu_group_get(dev);
 	if (!group) {
 		pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);

drivers/vfio/platform/vfio_platform_private.h

@@ -57,6 +57,7 @@ struct vfio_platform_device {
 	int				refcnt;
 	struct mutex			igate;
 	struct module			*parent_module;
+	const char			*compat;
 
 	/*
 	 * These fields should be filled by the bus specific binder