dm: core: add ofnode_count_phandle_with_args()

This function is usefull to get phandle number contained
in a property list.
For example,  this allows to allocate the right amount
of memory to keep clock's reference contained into the
"clocks" property.

To implement it, either of_count_phandle_with_args() or
fdtdec_parse_phandle_with_args() are used respectively
for live tree and flat tree.
By passing index = -1, these 2 functions returns the
number of phandle contained into the property list.

Add also the dev_count_phandle_with_args() based on
ofnode_count_phandle_with_args()

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 15ad5199c2f..8eecce59d10 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -433,6 +433,23 @@ int ofnode_parse_phandle_with_args(ofnode node, const char *list_name,
 				   struct ofnode_phandle_args *out_args);
 
 /**
+ * ofnode_count_phandle_with_args() - Count number of phandle in a list
+ *
+ * This function is useful to count phandles into a list.
+ * Returns number of phandle on success, on error returns appropriate
+ * errno value.
+ *
+ * @node:	device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @cells_name:	property name that specifies phandles' arguments count
+ * @return number of phandle on success, -ENOENT if @list_name does not
+ *      exist, -EINVAL if a phandle was not found, @cells_name could not
+ *      be found.
+ */
+int ofnode_count_phandle_with_args(ofnode node, const char *list_name,
+				   const char *cells_name);
+
+/**
  * ofnode_path() - find a node by full path
  *
  * @path: Full path to node, e.g. "/bus/spi@1"