dm: core: support reading a single indexed u32 value

The patch adds helper functions to allow reading a single indexed u32
value from a device-tree property containing multiple u32 values, that
is an array of integers.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reviewed-by: Simon Glass <sjg@chromium.org>

include/dm/of_access.h

@@ -234,6 +234,25 @@ struct device_node *of_find_node_by_phandle(phandle handle);
  */
 int of_read_u32(const struct device_node *np, const char *propname, u32 *outp);
 
+/**
+ * of_read_u32_index() - Find and read a 32-bit value from a multi-value
+ *                       property
+ *
+ * Search for a property in a device node and read a 32-bit value from
+ * it.
+ *
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @index:	index of the u32 in the list of values
+ * @outp:	pointer to return value, modified only if return value is 0.
+ *
+ * @return 0 on success, -EINVAL if the property does not exist,
+ * -ENODATA if property does not have a value, and -EOVERFLOW if the
+ * property data isn't large enough.
+ */
+int of_read_u32_index(const struct device_node *np, const char *propname,
+		      int index, u32 *outp);
+
 /**
  * of_read_u64() - Find and read a 64-bit integer from a property
  *

include/dm/ofnode.h

@@ -202,6 +202,18 @@ static inline ofnode ofnode_null(void)
  */
 int ofnode_read_u32(ofnode node, const char *propname, u32 *outp);
 
+/**
+ * ofnode_read_u32_index() - Read a 32-bit integer from a multi-value property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int ofnode_read_u32_index(ofnode node, const char *propname, int index,
+			  u32 *outp);
+
 /**
  * ofnode_read_s32() - Read a 32-bit integer from a property
  *
@@ -226,6 +238,19 @@ static inline int ofnode_read_s32(ofnode node, const char *propname,
  */
 u32 ofnode_read_u32_default(ofnode ref, const char *propname, u32 def);
 
+/**
+ * ofnode_read_u32_index_default() - Read a 32-bit integer from a multi-value
+ *                                   property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+u32 ofnode_read_u32_index_default(ofnode ref, const char *propname, int index,
+				  u32 def);
+
 /**
  * ofnode_read_s32_default() - Read a 32-bit integer from a property
  *

include/dm/read.h

@@ -66,6 +66,32 @@ int dev_read_u32(const struct udevice *dev, const char *propname, u32 *outp);
 int dev_read_u32_default(const struct udevice *dev, const char *propname,
 			 int def);
 
+/**
+ * dev_read_u32_index() - read an indexed 32-bit integer from a device's DT
+ *                        property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int dev_read_u32_index(struct udevice *dev, const char *propname, int index,
+		       u32 *outp);
+
+/**
+ * dev_read_u32_index_default() - read an indexed 32-bit integer from a device's
+ *                                DT property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+u32 dev_read_u32_index_default(struct udevice *dev, const char *propname,
+			       int index, u32 def);
+
 /**
  * dev_read_s32() - read a signed 32-bit integer from a device's DT property
  *
@@ -621,6 +647,20 @@ static inline int dev_read_u32_default(const struct udevice *dev,
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }
 
+static inline int dev_read_u32_index(struct udevice *dev,
+				     const char *propname, int index, u32 *outp)
+{
+	return ofnode_read_u32_index(dev_ofnode(dev), propname, index, outp);
+}
+
+static inline u32 dev_read_u32_index_default(struct udevice *dev,
+					     const char *propname, int index,
+					     u32 def)
+{
+	return ofnode_read_u32_index_default(dev_ofnode(dev), propname, index,
+					     def);
+}
+
 static inline int dev_read_s32(const struct udevice *dev,
 			       const char *propname, s32 *outp)
 {