core: Add functions to set properties in live-tree

Implement a set of functions to manipulate properties in a live device
tree:

* ofnode_write_prop() to set generic properties of a node
* ofnode_write_string() to set string properties of a node
* ofnode_set_enabled() to either enable or disable a node

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/core/ofnode.c

@@ -791,3 +791,73 @@ ofnode ofnode_by_prop_value(ofnode from, const char *propname,
 				propname, propval, proplen));
 	}
 }
+
+int ofnode_write_prop(ofnode node, const char *propname, int len,
+		      const void *value)
+{
+	const struct device_node *np = ofnode_to_np(node);
+	struct property *pp;
+	struct property *pp_last = NULL;
+	struct property *new;
+
+	if (!of_live_active())
+		return -ENOSYS;
+
+	if (!np)
+		return -EINVAL;
+
+	for (pp = np->properties; pp; pp = pp->next) {
+		if (strcmp(pp->name, propname) == 0) {
+			/* Property exists -> change value */
+			pp->value = (void *)value;
+			pp->length = len;
+			return 0;
+		}
+		pp_last = pp;
+	}
+
+	if (!pp_last)
+		return -ENOENT;
+
+	/* Property does not exist -> append new property */
+	new = malloc(sizeof(struct property));
+	if (!new)
+		return -ENOMEM;
+
+	new->name = strdup(propname);
+	if (!new->name)
+		return -ENOMEM;
+
+	new->value = (void *)value;
+	new->length = len;
+	new->next = NULL;
+
+	pp_last->next = new;
+
+	return 0;
+}
+
+int ofnode_write_string(ofnode node, const char *propname, const char *value)
+{
+	if (!of_live_active())
+		return -ENOSYS;
+
+	assert(ofnode_valid(node));
+
+	debug("%s: %s = %s", __func__, propname, value);
+
+	return ofnode_write_prop(node, propname, strlen(value) + 1, value);
+}
+
+int ofnode_set_enabled(ofnode node, bool value)
+{
+	if (!of_live_active())
+		return -ENOSYS;
+
+	assert(ofnode_valid(node));
+
+	if (value)
+		return ofnode_write_string(node, "status", "okay");
+	else
+		return ofnode_write_string(node, "status", "disable");
+}

include/dm/ofnode.h

@@ -764,4 +764,50 @@ u64 ofnode_translate_address(ofnode node, const fdt32_t *in_addr);
  * @return true if OK, false if the compatible is not found
  */
 int ofnode_device_is_compatible(ofnode node, const char *compat);
+
+/**
+ * ofnode_write_prop() - Set a property of a ofnode
+ *
+ * Note that the value passed to the function is *not* allocated by the
+ * function itself, but must be allocated by the caller if necessary.
+ *
+ * @node:	The node for whose property should be set
+ * @propname:	The name of the property to set
+ * @len:	The length of the new value of the property
+ * @value:	The new value of the property (must be valid prior to calling
+ *		the function)
+ * @return 0 if successful, -ve on error
+ */
+int ofnode_write_prop(ofnode node, const char *propname, int len,
+		      const void *value);
+
+/**
+ * ofnode_write_string() - Set a string property of a ofnode
+ *
+ * Note that the value passed to the function is *not* allocated by the
+ * function itself, but must be allocated by the caller if necessary.
+ *
+ * @node:	The node for whose string property should be set
+ * @propname:	The name of the string property to set
+ * @value:	The new value of the string property (must be valid prior to
+ *		calling the function)
+ * @return 0 if successful, -ve on error
+ */
+int ofnode_write_string(ofnode node, const char *propname, const char *value);
+
+/**
+ * ofnode_set_enabled() - Enable or disable a device tree node given by its
+ *			  ofnode
+ *
+ * This function effectively sets the node's "status" property to either "okay"
+ * or "disable", hence making it available for driver model initialization or
+ * not.
+ *
+ * @node:	The node to enable
+ * @value:	Flag that tells the function to either disable or enable the
+ *		node
+ * @return 0 if successful, -ve on error
+ */
+int ofnode_set_enabled(ofnode node, bool value);
+
 #endif