[PATCH RFC v3 15/35] of: fdt: Add of_flat_read_u32()

[Alexandru Elisei <alexandru.elisei@arm.com>]

Add the function of_flat_read_u32() to return the value of a property as
an u32.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
---

Changes since rfc v2:

* New patch, suggested by Rob Herring.

 drivers/of/fdt.c       | 21 +++++++++++++++++++++
 include/linux/of_fdt.h |  2 ++
 2 files changed, 23 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index bf502ba8da95..dfcd79fd5fd9 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -755,6 +755,27 @@ const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 	return fdt_getprop(initial_boot_params, node, name, size);
 }
 
+/*
+ * of_flat_read_u32 - Return the value of the given property as an u32.
+ *
+ * @node: device node from which the property value is to be read
+ * @propname: name of the property
+ * @out_value: the value of the property
+ * @return: 0 on success, -EINVAL if property does not exist
+ */
+int __init of_flat_read_u32(unsigned long node, const char *propname,
+			    u32 *out_value)
+{
+	const __be32 *reg;
+
+	reg = of_get_flat_dt_prop(node, propname, NULL);
+	if (!reg)
+		return -EINVAL;
+
+	*out_value = be32_to_cpup(reg);
+	return 0;
+}
+
 /**
  * of_fdt_is_compatible - Return true if given node from the given blob has
  * compat in its compatible list
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 0e26f8c3b10e..d7901699061b 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -57,6 +57,8 @@ extern const void *of_get_flat_dt_prop(unsigned long node, const char *name,
 extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
 extern unsigned long of_get_flat_dt_root(void);
 extern uint32_t of_get_flat_dt_phandle(unsigned long node);
+extern int of_flat_read_u32(unsigned long node, const char *propname,
+			    u32 *out_value);
 
 extern int early_init_dt_scan_chosen(char *cmdline);
 extern int early_init_dt_scan_memory(void);
-- 
2.43.0