dm: core: Add a function to read into a unsigned int

The current dev_read...() functions use s32 and u32 which are convenient
for device tree but not so useful for normal code, which often wants to
use normal integers for values.

Add a helper which supports returning an unsigned int. Also add signed
versions of the unsigned readers.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/dts/test.dts

@@ -87,6 +87,8 @@
 		test2-gpios = <&gpio_a 1>, <&gpio_a 4>, <&gpio_b 6 1 3 2 1>,
 			<&gpio_b 7 2 3 2 1>, <&gpio_b 8 4 3 2 1>,
 			<&gpio_b 9 0xc 3 2 1>;
+		int-value = <1234>;
+		uint-value = <(-1234)>;
 	};
 
 	junk {

drivers/core/read.c

@@ -21,6 +21,29 @@ int dev_read_u32_default(struct udevice *dev, const char *propname, int def)
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }
 
+int dev_read_s32(struct udevice *dev, const char *propname, s32 *outp)
+{
+	return ofnode_read_u32(dev_ofnode(dev), propname, (u32 *)outp);
+}
+
+int dev_read_s32_default(struct udevice *dev, const char *propname, int def)
+{
+	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
+}
+
+int dev_read_u32u(struct udevice *dev, const char *propname, uint *outp)
+{
+	u32 val;
+	int ret;
+
+	ret = ofnode_read_u32(dev_ofnode(dev), propname, &val);
+	if (ret)
+		return ret;
+	*outp = val;
+
+	return 0;
+}
+
 const char *dev_read_string(struct udevice *dev, const char *propname)
 {
 	return ofnode_read_string(dev_ofnode(dev), propname);

include/dm/read.h

@@ -64,6 +64,38 @@ int dev_read_u32(struct udevice *dev, const char *propname, u32 *outp);
  */
 int dev_read_u32_default(struct udevice *dev, const char *propname, int def);
 
+/**
+ * dev_read_s32() - read a signed 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_s32(struct udevice *dev, const char *propname, s32 *outp);
+
+/**
+ * dev_read_s32_default() - read a signed 32-bit int from a device's DT property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+int dev_read_s32_default(struct udevice *dev, const char *propname, int def);
+
+/**
+ * dev_read_u32u() - read a 32-bit integer from a device's DT property
+ *
+ * This version uses a standard uint type.
+ *
+ * @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_u32u(struct udevice *dev, const char *propname, uint *outp);
+
 /**
  * dev_read_string() - Read a string from a device's DT property
  *
@@ -492,6 +524,32 @@ static inline int dev_read_u32_default(struct udevice *dev,
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }
 
+static inline int dev_read_s32(struct udevice *dev,
+			       const char *propname, s32 *outp)
+{
+	return ofnode_read_s32(dev_ofnode(dev), propname, outp);
+}
+
+static inline int dev_read_s32_default(struct udevice *dev,
+				       const char *propname, int def)
+{
+	return ofnode_read_s32_default(dev_ofnode(dev), propname, def);
+}
+
+static inline int dev_read_u32u(struct udevice *dev,
+				const char *propname, uint *outp)
+{
+	u32 val;
+	int ret;
+
+	ret = ofnode_read_u32(dev_ofnode(dev), propname, &val);
+	if (ret)
+		return ret;
+	*outp = val;
+
+	return 0;
+}
+
 static inline const char *dev_read_string(struct udevice *dev,
 					  const char *propname)
 {

test/dm/test-fdt.c

@@ -736,3 +736,38 @@ static int dm_test_first_child(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_first_child, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test integer functions in dm_read_...() */
+static int dm_test_read_int(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+	u32 val32;
+	s32 sval;
+	uint val;
+
+	ut_assertok(uclass_first_device_err(UCLASS_TEST_FDT, &dev));
+	ut_asserteq_str("a-test", dev->name);
+	ut_assertok(dev_read_u32(dev, "int-value", &val32));
+	ut_asserteq(1234, val32);
+
+	ut_asserteq(-EINVAL, dev_read_u32(dev, "missing", &val32));
+	ut_asserteq(6, dev_read_u32_default(dev, "missing", 6));
+
+	ut_asserteq(1234, dev_read_u32_default(dev, "int-value", 6));
+	ut_asserteq(1234, val32);
+
+	ut_asserteq(-EINVAL, dev_read_s32(dev, "missing", &sval));
+	ut_asserteq(6, dev_read_s32_default(dev, "missing", 6));
+
+	ut_asserteq(-1234, dev_read_s32_default(dev, "uint-value", 6));
+	ut_assertok(dev_read_s32(dev, "uint-value", &sval));
+	ut_asserteq(-1234, sval);
+
+	val = 0;
+	ut_asserteq(-EINVAL, dev_read_u32u(dev, "missing", &val));
+	ut_assertok(dev_read_u32u(dev, "uint-value", &val));
+	ut_asserteq(-1234, val);
+
+	return 0;
+}
+DM_TEST(dm_test_read_int, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);