diff --git a/cmd/tpm-v1.c b/cmd/tpm-v1.c
index bf238a9f2e..0efb079b0a 100644
--- a/cmd/tpm-v1.c
+++ b/cmd/tpm-v1.c
@@ -131,7 +131,8 @@ static int do_tpm_extend(struct cmd_tbl *cmdtp, int flag, int argc,
 		return CMD_RET_FAILURE;
 	}
 
-	rc = tpm_pcr_extend(dev, index, in_digest, out_digest);
+	rc = tpm_pcr_extend(dev, index, in_digest, sizeof(in_digest),
+			    out_digest, "cmd");
 	if (!rc) {
 		puts("PCR value after execution of the command:\n");
 		print_byte_string(out_digest, sizeof(out_digest));
diff --git a/cmd/tpm_test.c b/cmd/tpm_test.c
index a3ccb12f53..b35eae81dc 100644
--- a/cmd/tpm_test.c
+++ b/cmd/tpm_test.c
@@ -91,7 +91,8 @@ static int test_early_extend(struct udevice *dev)
 	tpm_init(dev);
 	TPM_CHECK(tpm_startup(dev, TPM_ST_CLEAR));
 	TPM_CHECK(tpm_continue_self_test(dev));
-	TPM_CHECK(tpm_pcr_extend(dev, 1, value_in, value_out));
+	TPM_CHECK(tpm_pcr_extend(dev, 1, value_in, sizeof(value_in), value_out,
+				 "test"));
 	printf("done\n");
 	return 0;
 }
@@ -438,7 +439,7 @@ static int test_timing(struct udevice *dev)
 		   100);
 	TTPM_CHECK(tpm_nv_read_value(dev, INDEX0, (uint8_t *)&x, sizeof(x)),
 		   100);
-	TTPM_CHECK(tpm_pcr_extend(dev, 0, in, out), 200);
+	TTPM_CHECK(tpm_pcr_extend(dev, 0, in, sizeof(in), out, "test"), 200);
 	TTPM_CHECK(tpm_set_global_lock(dev), 50);
 	TTPM_CHECK(tpm_tsc_physical_presence(dev, PHYS_PRESENCE), 100);
 	printf("done\n");
diff --git a/include/tpm_api.h b/include/tpm_api.h
index 11aa14eb79..8979d9d6df 100644
--- a/include/tpm_api.h
+++ b/include/tpm_api.h
@@ -81,14 +81,16 @@ u32 tpm_nv_write_value(struct udevice *dev, u32 index, const void *data,
  *
  * @param dev		TPM device
  * @param index		index of the PCR
- * @param in_digest	160-bit value representing the event to be
+ * @param in_digest	160/256-bit value representing the event to be
  *			recorded
- * @param out_digest	160-bit PCR value after execution of the
+ * @param size		size of digest in bytes
+ * @param out_digest	160/256-bit PCR value after execution of the
  *			command
+ * @param name		digest source, used for log output
  * Return: return code of the operation
  */
 u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest,
-		   void *out_digest);
+		   uint size, void *out_digest, const char *name);
 
 /**
  * Issue a TPM_PCRRead command.
diff --git a/lib/tpm-v2.c b/lib/tpm-v2.c
index 1bf627853a..6058f2e1e4 100644
--- a/lib/tpm-v2.c
+++ b/lib/tpm-v2.c
@@ -157,6 +157,8 @@ u32 tpm2_pcr_extend(struct udevice *dev, u32 index, u32 algorithm,
 	};
 	int ret;
 
+	if (!digest)
+		return -EINVAL;
 	/*
 	 * Fill the command structure starting from the first buffer:
 	 *     - the digest
diff --git a/lib/tpm_api.c b/lib/tpm_api.c
index 032f383ca0..7e8df8795e 100644
--- a/lib/tpm_api.c
+++ b/lib/tpm_api.c
@@ -140,15 +140,17 @@ u32 tpm_write_lock(struct udevice *dev, u32 index)
 }
 
 u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest,
-		   void *out_digest)
+		   uint size, void *out_digest, const char *name)
 {
-	if (tpm_is_v1(dev))
+	if (tpm_is_v1(dev)) {
 		return tpm1_extend(dev, index, in_digest, out_digest);
-	else if (tpm_is_v2(dev))
+	} else if (tpm_is_v2(dev)) {
 		return tpm2_pcr_extend(dev, index, TPM2_ALG_SHA256, in_digest,
 				       TPM2_DIGEST_LEN);
-	else
+		/* @name is ignored as we do not support the TPM log here */
+	} else {
 		return -ENOSYS;
+	}
 }
 
 u32 tpm_pcr_read(struct udevice *dev, u32 index, void *data, size_t count)