From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Sometimes it needs to check if there is a node in FDT by full path.
Introduce this helper to get the specified name subnode if it exists.
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
CC: Rob Herring <robh@xxxxxxxxxx>
---
drivers/of/fdt.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/of_fdt.h | 2 ++
2 files changed, 37 insertions(+)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 655f79d..112ec16 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -645,6 +645,41 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node,
}
/**
+ * of_get_flat_dt_subnode_by_name - get subnode of specified node by name
+ *
+ * @node: the parent node
+ * @uname: the name of subnode
+ * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
+ */
+
+int of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
+{
+ const void *blob = initial_boot_params;
+ int offset;
+ const char *pathp;
+
+ /* Find first subnode if it exists */
+ offset = fdt_first_subnode(blob, node);
+ if (offset < 0)
+ return -FDT_ERR_NOTFOUND;
+ pathp = fdt_get_name(blob, offset, NULL);
+ if (strncmp(pathp, uname, strlen(uname)) == 0)
+ return offset;
+
+ /* Find other subnodes */
+ do {
+ offset = fdt_next_subnode(blob, offset);
+ if (offset < 0)
+ return -FDT_ERR_NOTFOUND;
+ pathp = fdt_get_name(blob, offset, NULL);
+ if (strncmp(pathp, uname, strlen(uname)) == 0)
+ return offset;
+ } while (offset >= 0);
+
+ return -FDT_ERR_NOTFOUND;
+}
+
+/**
* of_get_flat_dt_root - find the root node in the flat blob
*/
unsigned long __init of_get_flat_dt_root(void)
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index df9ef38..fc28162 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -52,6 +52,8 @@ extern char __dtb_end[];
extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
int depth, void *data),
void *data);
+extern int of_get_flat_dt_subnode_by_name(unsigned long node,
+ const char *uname);
extern const void *of_get_flat_dt_prop(unsigned long node, const char *name,
int *size);
extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
--
2.0.4
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