diff --git a/docs/mmio.md b/docs/mmio.md
index 3883ffa..8884ba0 100644
--- a/docs/mmio.md
+++ b/docs/mmio.md
@@ -164,13 +164,11 @@ The periphery MMIO functions return 0 on success or one of the negative error co
 
 The libc errno of the failure in an underlying libc library call can be obtained with the `mmio_errno()` helper function. A human readable error message can be obtained with the `mmio_errmsg()` helper function.
 
-| Error Code            | Description                   |
-|-----------------------|-------------------------------|
-| `MMIO_ERROR_ARG`      | Invalid arguments             |
-| `MMIO_ERROR_OPEN`     | Opening /dev/mem              |
-| `MMIO_ERROR_MAP`      | Mapping memory                |
-| `MMIO_ERROR_CLOSE`    | Closing /dev/mem              |
-| `MMIO_ERROR_UNMAP`    | Unmapping memory              |
+| Error Code            | Description           |
+|-----------------------|-----------------------|
+| `MMIO_ERROR_ARG`      | Invalid arguments     |
+| `MMIO_ERROR_OPEN`     | Opening MMIO          |
+| `MMIO_ERROR_CLOSE`    | Closing MMIO          |
 
 ### EXAMPLE
 
diff --git a/src/mmio.c b/src/mmio.c
index 93787df..9b2a0db 100644
--- a/src/mmio.c
+++ b/src/mmio.c
@@ -73,7 +73,7 @@ int mmio_open(mmio_t *mmio, uintptr_t base, size_t size) {
     if ((mmio->ptr = mmap(0, mmio->aligned_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, mmio->aligned_base)) == MAP_FAILED) {
         int errsv = errno;
         close(fd);
-        return _mmio_error(mmio, MMIO_ERROR_MAP, errsv, "Mapping memory");
+        return _mmio_error(mmio, MMIO_ERROR_OPEN, errsv, "Mapping memory");
     }
 
     /* Close memory */
@@ -171,7 +171,7 @@ int mmio_close(mmio_t *mmio) {
 
     /* Unmap memory */
     if (munmap(mmio->ptr, mmio->aligned_size) < 0)
-        return _mmio_error(mmio, MMIO_ERROR_UNMAP, errno, "Unmapping memory");
+        return _mmio_error(mmio, MMIO_ERROR_CLOSE, errno, "Unmapping memory");
 
     mmio->ptr = 0;
 
diff --git a/src/mmio.h b/src/mmio.h
index 3459901..c64454a 100644
--- a/src/mmio.h
+++ b/src/mmio.h
@@ -17,10 +17,8 @@ extern "C" {
 
 enum mmio_error_code {
     MMIO_ERROR_ARG          = -1, /* Invalid arguments */
-    MMIO_ERROR_OPEN         = -2, /* Opening /dev/mem */
-    MMIO_ERROR_MAP          = -3, /* Mapping memory */
-    MMIO_ERROR_CLOSE        = -4, /* Closing /dev/mem */
-    MMIO_ERROR_UNMAP        = -5, /* Unmapping memory */
+    MMIO_ERROR_OPEN         = -2, /* Opening MMIO */
+    MMIO_ERROR_CLOSE        = -3, /* Closing MMIO */
 };
 
 typedef struct mmio_handle mmio_t;