[PATCH v4 1/8] libfdt: Add a subnodes iterator macro
From: Maxime Ripard <hidden>
Date: 2016-07-27 12:55:53
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Thierry Reding <redacted> The fdt_for_each_subnode() iterator macro provided by this patch can be used to iterate over a device tree node's subnodes. At each iteration a loop variable will be set to the next subnode. Signed-off-by: Thierry Reding <redacted> Signed-off-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> --- libfdt/libfdt.h | 28 ++++++++++++++++++++++++++++ tests/subnode_iterate.c | 8 ++------ 2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 36222fd4a6f4..911e548163d8 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h@@ -168,6 +168,34 @@ int fdt_first_subnode(const void *fdt, int offset); */ int fdt_next_subnode(const void *fdt, int offset); +/** + * fdt_for_each_subnode - iterate over all subnodes of a parent + * + * @node: child node (int, lvalue) + * @fdt: FDT blob (const void *) + * @parent: parent node (int) + * + * This is actually a wrapper around a for loop and would be used like so: + * + * fdt_for_each_subnode(node, fdt, parent) { + * Use node + * ... + * } + * + * if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) { + * Error handling + * } + * + * Note that this is implemented as a macro and @node is used as + * iterator in the loop. The parent variable be constant or even a + * literal. + * + */ +#define fdt_for_each_subnode(node, fdt, parent) \ + for (node = fdt_first_subnode(fdt, parent); \ + node >= 0; \ + node = fdt_next_subnode(fdt, node)) + /**********************************************************************/ /* General functions */ /**********************************************************************/
diff --git a/tests/subnode_iterate.c b/tests/subnode_iterate.c
index b9f379d5963c..0fb5c901ebd7 100644
--- a/tests/subnode_iterate.c
+++ b/tests/subnode_iterate.c@@ -48,9 +48,7 @@ static void test_node(void *fdt, int parent_offset) subnodes = cpu_to_fdt32(*prop); count = 0; - for (offset = fdt_first_subnode(fdt, parent_offset); - offset >= 0; - offset = fdt_next_subnode(fdt, offset)) + fdt_for_each_subnode(offset, fdt, parent_offset) count++; if (count != subnodes) {
@@ -65,9 +63,7 @@ static void check_fdt_next_subnode(void *fdt) int offset; int count = 0; - for (offset = fdt_first_subnode(fdt, 0); - offset >= 0; - offset = fdt_next_subnode(fdt, offset)) { + fdt_for_each_subnode(offset, fdt, 0) { test_node(fdt, offset); count++; }
--
2.9.2