diff --git a/sys/amd64/conf/DEFAULTS b/sys/amd64/conf/DEFAULTS
--- a/sys/amd64/conf/DEFAULTS
+++ b/sys/amd64/conf/DEFAULTS
@@ -26,3 +26,6 @@
 options 	CC_CUBIC		# include CUBIC congestion control
 
 options 	NETLINK			# netlink(4) support
+
+# random(4)
+options 	RANDOM_ENABLE_TPM	# enable entropy from TPM 2.0
diff --git a/sys/arm/conf/DEFAULTS b/sys/arm/conf/DEFAULTS
--- a/sys/arm/conf/DEFAULTS
+++ b/sys/arm/conf/DEFAULTS
@@ -8,3 +8,6 @@
 options 	CC_CUBIC		# include CUBIC congestion control
 
 options 	INTRNG			# All arm systems use INTRNG these days
+
+# random(4)
+options 	RANDOM_ENABLE_TPM	# enable entropy from TPM 2.0
diff --git a/sys/arm64/conf/DEFAULTS b/sys/arm64/conf/DEFAULTS
--- a/sys/arm64/conf/DEFAULTS
+++ b/sys/arm64/conf/DEFAULTS
@@ -18,3 +18,6 @@
 options 	INTRNG
 
 options 	NETLINK			# netlink(4) support
+
+# random(4)
+options 	RANDOM_ENABLE_TPM	# enable entropy from TPM 2.0
diff --git a/sys/conf/NOTES b/sys/conf/NOTES
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -2829,6 +2829,8 @@
 # environment.
 options 	RANDOM_ENABLE_ETHER	# ether_input
 
+options 	RANDOM_ENABLE_TPM	# implies TPM_HARVEST
+
 # Module to enable execution of application via emulators like QEMU
 options         IMGACT_BINMISC
 
diff --git a/sys/conf/options b/sys/conf/options
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -960,6 +960,7 @@
 # the uma slab allocator.
 RANDOM_ENABLE_UMA	opt_global.h
 RANDOM_ENABLE_ETHER	opt_global.h
+RANDOM_ENABLE_TPM	opt_global.h
 
 # This options turns TPM into entropy source.
 TPM_HARVEST	opt_tpm.h
diff --git a/sys/dev/tpm/tpm20.c b/sys/dev/tpm/tpm20.c
--- a/sys/dev/tpm/tpm20.c
+++ b/sys/dev/tpm/tpm20.c
@@ -42,7 +42,7 @@
 MALLOC_DEFINE(M_TPM20, "tpm_buffer", "buffer for tpm 2.0 driver");
 
 static void tpm20_discard_buffer(void *arg);
-#ifdef TPM_HARVEST
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
 static void tpm20_harvest(void *arg, int unused);
 #endif
 static int  tpm20_save_state(device_t dev, bool suspend);
@@ -184,7 +184,7 @@
 	return (ENOTTY);
 }
 
-#ifdef TPM_HARVEST
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
 static const struct random_source random_tpm = {
 	.rs_ident = "TPM",
 	.rs_source = RANDOM_PURE_TPM,
@@ -212,7 +212,7 @@
 	if (result != 0)
 		tpm20_release(sc);
 
-#ifdef TPM_HARVEST
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
 	random_source_register(&random_tpm);
 	TIMEOUT_TASK_INIT(taskqueue_thread, &sc->harvest_task, 0,
 	    tpm20_harvest, sc);
@@ -227,7 +227,7 @@
 tpm20_release(struct tpm_sc *sc)
 {
 
-#ifdef TPM_HARVEST
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
 	if (device_is_attached(sc->dev))
 		taskqueue_drain_timeout(taskqueue_thread, &sc->harvest_task);
 	random_source_deregister(&random_tpm);
@@ -254,7 +254,7 @@
 	return (tpm20_save_state(dev, false));
 }
 
-#ifdef TPM_HARVEST
+#if defined TPM_HARVEST || defined RANDOM_ENABLE_TPM
 /*
  * Get TPM_HARVEST_SIZE random bytes and add them
  * into system entropy pool.
diff --git a/sys/riscv/conf/DEFAULTS b/sys/riscv/conf/DEFAULTS
--- a/sys/riscv/conf/DEFAULTS
+++ b/sys/riscv/conf/DEFAULTS
@@ -18,3 +18,6 @@
 options 	INTRNG
 
 options 	NETLINK			# netlink(4) support
+
+# random(4)
+options 	RANDOM_ENABLE_TPM	# enable entropy from TPM 2.0