diff --git a/tools/intel_reg.c b/tools/intel_reg.c
index fb3461f7..84b3c9de 100644
--- a/tools/intel_reg.c
+++ b/tools/intel_reg.c
@@ -630,6 +630,11 @@ static int intel_reg_help(struct config *config, int argc, char *argv[])
 	printf("REGISTER is defined as:\n");
         printf("  [(PORTNAME|PORTNUM|MMIO-OFFSET):](REGNAME|REGADDR)\n");
 
+	printf("\n");
+	printf("PORTNAME is one of:\n");
+	intel_reg_spec_print_ports();
+	printf("\n");
+
 	printf("\n");
 	printf("OPTIONS common to most COMMANDS:\n");
 	printf(" --spec=PATH    Read register spec from directory or file\n");
diff --git a/tools/intel_reg_spec.c b/tools/intel_reg_spec.c
index b49e0dcd..5594d707 100644
--- a/tools/intel_reg_spec.c
+++ b/tools/intel_reg_spec.c
@@ -343,3 +343,11 @@ void intel_reg_spec_free(struct reg *regs, size_t n)
 	}
 	free(regs);
 }
+
+void intel_reg_spec_print_ports(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(port_descs); i++)
+		printf("%s%s", i == 0 ? "" : ", ", port_descs[i].name);
+}
diff --git a/tools/intel_reg_spec.h b/tools/intel_reg_spec.h
index 26e82523..dcb31430 100644
--- a/tools/intel_reg_spec.h
+++ b/tools/intel_reg_spec.h
@@ -73,5 +73,6 @@ ssize_t intel_reg_spec_file(struct reg **regs, const char *filename);
 void intel_reg_spec_free(struct reg *regs, size_t n);
 int intel_reg_spec_decode(char *buf, size_t bufsize, const struct reg *reg,
 			  uint32_t val, uint32_t devid);
+void intel_reg_spec_print_ports(void);
 
 #endif /* __INTEL_REG_SPEC_H__ */