Merge #322

322: Once r=therealprof a=burrbull

r? @therealprof 

#264 was taken as base.

![изображение](https://user-images.githubusercontent.com/3072754/61576487-59a82280-aae3-11e9-9165-aefbf41b2925.png)


Co-authored-by: Hugo van der Wijst <[email protected]>
Co-authored-by: Andrey Zgarbul <[email protected]>

Author: 3 people

src/generate/register.rs

@@ -39,7 +39,10 @@ pub fn render(
     let mut r_impl_items = vec![];
     let mut w_impl_items = vec![];
 
-    if access == Access::ReadWrite {
+    let can_read = [Access::ReadOnly, Access::ReadWriteOnce, Access::ReadWrite].contains(&access);
+    let can_write = access != Access::ReadOnly;
+
+    if access == Access::ReadWrite || access == Access::ReadWriteOnce {
         reg_impl_items.push(quote! {
             /// Modifies the contents of the register
             #[inline]
@@ -53,7 +56,7 @@ pub fn render(
         });
     }
 
-    if access == Access::ReadOnly || access == Access::ReadWrite {
+    if can_read {
         reg_impl_items.push(quote! {
             /// Reads the contents of the register
             #[inline]
@@ -78,7 +81,7 @@ pub fn render(
         });
     }
 
-    if access == Access::WriteOnly || access == Access::ReadWrite {
+    if can_write {
         reg_impl_items.push(quote! {
             /// Writes to the register
             #[inline]
@@ -157,15 +160,15 @@ pub fn render(
         }
     }
 
-    if access == Access::ReadOnly || access == Access::ReadWrite {
+    if can_read {
         mod_items.push(quote! {
             impl R {
                 #(#r_impl_items)*
             }
         });
     }
 
-    if access == Access::WriteOnly || access == Access::ReadWrite {
+    if can_write {
         mod_items.push(quote! {
             impl W {
                 #(#w_impl_items)*
@@ -266,9 +269,9 @@ pub fn fields(
     let fs = fields.iter().map(F::from).collect::<Result<Vec<_>>>()?;
 
     // TODO enumeratedValues
-    if access == Access::ReadOnly || access == Access::ReadWrite {
+    if [Access::ReadOnly, Access::ReadWriteOnce, Access::ReadWrite].contains(&access) {
         for f in &fs {
-            if f.access == Some(Access::WriteOnly) {
+            if f.access == Some(Access::WriteOnly) || f.access == Some(Access::WriteOnce) {
                 continue;
             }
 
@@ -556,7 +559,7 @@ pub fn fields(
         }
     }
 
-    if access == Access::WriteOnly || access == Access::ReadWrite {
+    if access != Access::ReadOnly {
         for f in &fs {
             if f.access == Some(Access::ReadOnly) {
                 continue;

src/util.rs

@@ -200,7 +200,11 @@ pub fn access_of(register: &Register) -> Access {
         if let Some(fields) = &register.fields {
             if fields.iter().all(|f| f.access == Some(Access::ReadOnly)) {
                 Access::ReadOnly
-            } else if fields.iter().all(|f| f.access == Some(Access::WriteOnly)) {
+            } else if fields.iter().all(|f| f.access == Some(Access::WriteOnce)) {
+                Access::WriteOnce
+            } else if fields.iter().all(|f| f.access == Some(Access::ReadWriteOnce)) {
+                Access::ReadWriteOnce
+            } else if fields.iter().all(|f| f.access == Some(Access::WriteOnly) || f.access == Some(Access::WriteOnce)) {
                 Access::WriteOnly
             } else {
                 Access::ReadWrite