[U-Boot] [PATCH 1/8] dm: add dev_read_u32()

[Masahiro Yamada]

dev_read_u32_default() always returns something even when the property
is missing.  So, it is impossible to do nothing in the case.  One
solution is to use ofnode_read_u32() instead, but adding dev_read_u32()
will be helpful.

BTW, Linux has an equvalent function, device_property_read_u32();
it is clearer that it reads a property.  I cannot understand the
behavior of dev_read_u32() from its name.

Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
---

BTW, I do not understand why we want *_default helpers.
It is pretty easy to do equivalent without _default.

  priv->val = default;    /* default in case property is missing */
  dev_read_u32(dev, "foo-property", &priv->val);

On the other hand, if we want to do nothing for missing property,
we will end up with clumsy code.

  /* we do not want to overwrite priv->val if property is missing */
  if (dev_read_bool(dev, "foo-property") {
         /* default value '0' will not be used anyway */
         priv->val = dev_read_u32_default(dev, "foo-property", 0);
  }

One more BTW, it was just painful to write equivalent code twice
for CONFIG_DM_DEV_READ_INLINE.


 drivers/core/read.c |  5 +++++
 include/dm/read.h   | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/core/read.c b/drivers/core/read.c
index 5d440ce..e027041 100644
--- a/drivers/core/read.c
+++ b/drivers/core/read.c
@@ -10,6 +10,11 @@
 #include <mapmem.h>
 #include <dm/of_access.h>
 
+int dev_read_u32(struct udevice *dev, const char *propname, u32 *outp)
+{
+	return ofnode_read_u32(dev_ofnode(dev), propname, outp);
+}
+
 int dev_read_u32_default(struct udevice *dev, const char *propname, int def)
 {
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
diff --git a/include/dm/read.h b/include/dm/read.h
index 8114037..5cacec8 100644
--- a/include/dm/read.h
+++ b/include/dm/read.h
@@ -46,6 +46,16 @@ static inline bool dev_of_valid(struct udevice *dev)
 
 #ifndef CONFIG_DM_DEV_READ_INLINE
 /**
+ * dev_read_u32() - read a 32-bit integer from a device's DT property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int dev_read_u32(struct udevice *dev, const char *propname, u32 *outp);
+
+/**
  * dev_read_u32_default() - read a 32-bit integer from a device's DT property
  *
  * @dev:	device to read DT property from
@@ -412,6 +422,12 @@ int dev_read_resource_byname(struct udevice *dev, const char *name,
 
 #else /* CONFIG_DM_DEV_READ_INLINE is enabled */
 
+static inline int dev_read_u32(struct udevice *dev,
+			       const char *propname, u32 *outp)
+{
+	return ofnode_read_u32(dev_ofnode(dev), propname, outp);
+}
+
 static inline int dev_read_u32_default(struct udevice *dev,
 				       const char *propname, int def)
 {
-- 
2.7.4