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>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index 96a5dd2..5bc3b02 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -48,6 +48,46 @@ u32 ofnode_read_u32_default(ofnode node, const char *propname, u32 def)
 	return def;
 }
 
+int ofnode_read_u32_index(ofnode node, const char *propname, int index,
+			  u32 *outp)
+{
+	const fdt32_t *cell;
+	int len;
+
+	assert(ofnode_valid(node));
+	debug("%s: %s: ", __func__, propname);
+
+	if (ofnode_is_np(node))
+		return of_read_u32_index(ofnode_to_np(node), propname, index,
+					 outp);
+
+	cell = fdt_getprop(gd->fdt_blob, ofnode_to_offset(node), propname,
+			   &len);
+	if (!cell) {
+		debug("(not found)\n");
+		return -EINVAL;
+	}
+
+	if (len < (sizeof(int) * (index + 1))) {
+		debug("(not large enough)\n");
+		return -EOVERFLOW;
+	}
+
+	*outp = fdt32_to_cpu(cell[index]);
+	debug("%#x (%d)\n", *outp, *outp);
+
+	return 0;
+}
+
+u32 ofnode_read_u32_index_default(ofnode node, const char *propname, int index,
+				  u32 def)
+{
+	assert(ofnode_valid(node));
+	ofnode_read_u32_index(node, propname, index, &def);
+
+	return def;
+}
+
 int ofnode_read_s32_default(ofnode node, const char *propname, s32 def)
 {
 	assert(ofnode_valid(node));