[PATCH v3 02/18] of: base: add of_parse_phandle_with_optional_args()
From: Michael Walle <hidden>
Date: 2022-11-18 18:52:23
Also in:
linux-arm-kernel, linux-doc, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
Add a new variant of the of_parse_phandle_with_args() which treats the cells name as optional. If it's missing, it is assumed that the phandle has no arguments. Up until now, a nvmem node didn't have any arguments, so all the device trees haven't any '#*-cells' property. But there is a need for an additional argument for the phandle, for which we need a '#*-cells' property. Therefore, we need to support nvmem nodes with and without this property. Signed-off-by: Michael Walle <redacted> Reviewed-by: Rob Herring <robh@kernel.org> --- changes since v2: - none changes since v1: - none include/linux/of.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/include/linux/of.h b/include/linux/of.h
index 8b9f94386dc3..98c252d2d851 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h@@ -1008,6 +1008,31 @@ static inline int of_parse_phandle_with_fixed_args(const struct device_node *np, index, out_args); } +/** + * of_parse_phandle_with_optional_args() - Find a node pointed by phandle in a list + * @np: pointer to a device tree node containing a list + * @list_name: property name that contains a list + * @cells_name: property name that specifies phandles' arguments count + * @index: index of a phandle to parse out + * @out_args: optional pointer to output arguments structure (will be filled) + * + * Same as of_parse_phandle_with_args() except that if the cells_name property + * is not found, cell_count of 0 is assumed. + * + * This is used to useful, if you have a phandle which didn't have arguments + * before and thus doesn't have a '#*-cells' property but is now migrated to + * having arguments while retaining backwards compatibility. + */ +static inline int of_parse_phandle_with_optional_args(const struct device_node *np, + const char *list_name, + const char *cells_name, + int index, + struct of_phandle_args *out_args) +{ + return __of_parse_phandle_with_args(np, list_name, cells_name, + 0, index, out_args); +} + /** * of_property_count_u8_elems - Count the number of u8 elements in a property *
--
2.30.2