diff --git a/drivers/firmware/arm_ffa/bus.c b/drivers/firmware/arm_ffa/bus.c
index 83166e02b19184e837b67b22b658f61c7be5fd87..00fe595a5bc8972ffc90363cda045b234d96dc01 100644
--- a/drivers/firmware/arm_ffa/bus.c
+++ b/drivers/firmware/arm_ffa/bus.c
@@ -46,9 +46,6 @@ static int ffa_device_probe(struct device *dev)
 	struct ffa_driver *ffa_drv = to_ffa_driver(dev->driver);
 	struct ffa_device *ffa_dev = to_ffa_dev(dev);
 
-	if (!ffa_device_match(dev, dev->driver))
-		return -ENODEV;
-
 	return ffa_drv->probe(ffa_dev);
 }
 
@@ -99,6 +96,9 @@ int ffa_driver_register(struct ffa_driver *driver, struct module *owner,
 {
 	int ret;
 
+	if (!driver->probe)
+		return -EINVAL;
+
 	driver->driver.bus = &ffa_bus_type;
 	driver->driver.name = driver->name;
 	driver->driver.owner = owner;
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index b1edb4b2e94aaf32af5d7eddc459aac71e22634c..c9fb56afbcb494230c604d4dfd3479726af6631f 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -120,7 +120,7 @@
 #define PACK_TARGET_INFO(s, r)		\
 	(FIELD_PREP(SENDER_ID_MASK, (s)) | FIELD_PREP(RECEIVER_ID_MASK, (r)))
 
-/**
+/*
  * FF-A specification mentions explicitly about '4K pages'. This should
  * not be confused with the kernel PAGE_SIZE, which is the translation
  * granule kernel is configured and may be one among 4K, 16K and 64K.
@@ -149,8 +149,10 @@ static const int ffa_linux_errmap[] = {
 
 static inline int ffa_to_linux_errno(int errno)
 {
-	if (errno < FFA_RET_SUCCESS && errno >= -ARRAY_SIZE(ffa_linux_errmap))
-		return ffa_linux_errmap[-errno];
+	int err_idx = -errno;
+
+	if (err_idx >= 0 && err_idx < ARRAY_SIZE(ffa_linux_errmap))
+		return ffa_linux_errmap[err_idx];
 	return -EINVAL;
 }