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>

arch/sandbox/dts/test.dts

@@ -94,6 +94,7 @@
 		int-value = <1234>;
 		uint-value = <(-1234)>;
 		int64-value = /bits/ 64 <0x1111222233334444>;
+		int-array = <5678 9123 4567>;
 		interrupts-extended = <&irq 3 0>;
 	};
 

drivers/core/of_access.c

@@ -485,6 +485,28 @@ int of_read_u32_array(const struct device_node *np, const char *propname,
 	return 0;
 }
 
+int of_read_u32_index(const struct device_node *np, const char *propname,
+		      int index, u32 *outp)
+{
+	const __be32 *val;
+
+	debug("%s: %s: ", __func__, propname);
+	if (!np)
+		return -EINVAL;
+
+	val = of_find_property_value_of_size(np, propname,
+					     sizeof(*outp) * (index + 1));
+	if (IS_ERR(val)) {
+		debug("(not found)\n");
+		return PTR_ERR(val);
+	}
+
+	*outp = be32_to_cpup(val + index);
+	debug("%#x (%d)\n", *outp, *outp);
+
+	return 0;
+}
+
 int of_read_u64(const struct device_node *np, const char *propname, u64 *outp)
 {
 	const __be64 *val;

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));

drivers/core/read.c

@@ -22,6 +22,19 @@ int dev_read_u32_default(const struct udevice *dev, const char *propname,
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }
 
+int dev_read_u32_index(struct udevice *dev, const char *propname, int index,
+		       u32 *outp)
+{
+	return ofnode_read_u32_index(dev_ofnode(dev), propname, index, outp);
+}
+
+u32 dev_read_u32_index_default(struct udevice *dev, const char *propname,
+			       int index, u32 def)
+{
+	return ofnode_read_u32_index_default(dev_ofnode(dev), propname, index,
+					     def);
+}
+
 int dev_read_s32(const struct udevice *dev, const char *propname, s32 *outp)
 {
 	return ofnode_read_u32(dev_ofnode(dev), propname, (u32 *)outp);

include/dm/of_access.h

@@ -234,6 +234,25 @@ struct device_node *of_find_node_by_phandle(phandle handle);
  */
 int of_read_u32(const struct device_node *np, const char *propname, u32 *outp);
 
+/**
+ * of_read_u32_index() - Find and read a 32-bit value from a multi-value
+ *                       property
+ *
+ * Search for a property in a device node and read a 32-bit value from
+ * it.
+ *
+ * @np:		device node from which the property value is to be read.
+ * @propname:	name of the property to be searched.
+ * @index:	index of the u32 in the list of values
+ * @outp:	pointer to return value, modified only if return value is 0.
+ *
+ * @return 0 on success, -EINVAL if the property does not exist,
+ * -ENODATA if property does not have a value, and -EOVERFLOW if the
+ * property data isn't large enough.
+ */
+int of_read_u32_index(const struct device_node *np, const char *propname,
+		      int index, u32 *outp);
+
 /**
  * of_read_u64() - Find and read a 64-bit integer from a property
  *

include/dm/ofnode.h

@@ -202,6 +202,18 @@ static inline ofnode ofnode_null(void)
  */
 int ofnode_read_u32(ofnode node, const char *propname, u32 *outp);
 
+/**
+ * ofnode_read_u32_index() - Read a 32-bit integer from a multi-value property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int ofnode_read_u32_index(ofnode node, const char *propname, int index,
+			  u32 *outp);
+
 /**
  * ofnode_read_s32() - Read a 32-bit integer from a property
  *
@@ -226,6 +238,19 @@ static inline int ofnode_read_s32(ofnode node, const char *propname,
  */
 u32 ofnode_read_u32_default(ofnode ref, const char *propname, u32 def);
 
+/**
+ * ofnode_read_u32_index_default() - Read a 32-bit integer from a multi-value
+ *                                   property
+ *
+ * @ref:	valid node reference to read property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+u32 ofnode_read_u32_index_default(ofnode ref, const char *propname, int index,
+				  u32 def);
+
 /**
  * ofnode_read_s32_default() - Read a 32-bit integer from a property
  *

include/dm/read.h

@@ -66,6 +66,32 @@ int dev_read_u32(const struct udevice *dev, const char *propname, u32 *outp);
 int dev_read_u32_default(const struct udevice *dev, const char *propname,
 			 int def);
 
+/**
+ * dev_read_u32_index() - read an indexed 32-bit integer from a device's DT
+ *                        property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @outp:	place to put value (if found)
+ * @return 0 if OK, -ve on error
+ */
+int dev_read_u32_index(struct udevice *dev, const char *propname, int index,
+		       u32 *outp);
+
+/**
+ * dev_read_u32_index_default() - read an indexed 32-bit integer from a device's
+ *                                DT property
+ *
+ * @dev:	device to read DT property from
+ * @propname:	name of the property to read from
+ * @index:	index of the integer to return
+ * @def:	default value to return if the property has no value
+ * @return property value, or @def if not found
+ */
+u32 dev_read_u32_index_default(struct udevice *dev, const char *propname,
+			       int index, u32 def);
+
 /**
  * dev_read_s32() - read a signed 32-bit integer from a device's DT property
  *
@@ -621,6 +647,20 @@ static inline int dev_read_u32_default(const struct udevice *dev,
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }
 
+static inline int dev_read_u32_index(struct udevice *dev,
+				     const char *propname, int index, u32 *outp)
+{
+	return ofnode_read_u32_index(dev_ofnode(dev), propname, index, outp);
+}
+
+static inline u32 dev_read_u32_index_default(struct udevice *dev,
+					     const char *propname, int index,
+					     u32 def)
+{
+	return ofnode_read_u32_index_default(dev_ofnode(dev), propname, index,
+					     def);
+}
+
 static inline int dev_read_s32(const struct udevice *dev,
 			       const char *propname, s32 *outp)
 {

test/dm/test-fdt.c

@@ -905,6 +905,35 @@ static int dm_test_read_int(struct unit_test_state *uts)
 }
 DM_TEST(dm_test_read_int, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
 
+static int dm_test_read_int_index(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+	u32 val32;
+
+	ut_assertok(uclass_first_device_err(UCLASS_TEST_FDT, &dev));
+	ut_asserteq_str("a-test", dev->name);
+
+	ut_asserteq(-EINVAL, dev_read_u32_index(dev, "missing", 0, &val32));
+	ut_asserteq(19, dev_read_u32_index_default(dev, "missing", 0, 19));
+
+	ut_assertok(dev_read_u32_index(dev, "int-array", 0, &val32));
+	ut_asserteq(5678, val32);
+	ut_assertok(dev_read_u32_index(dev, "int-array", 1, &val32));
+	ut_asserteq(9123, val32);
+	ut_assertok(dev_read_u32_index(dev, "int-array", 2, &val32));
+	ut_asserteq(4567, val32);
+	ut_asserteq(-EOVERFLOW, dev_read_u32_index(dev, "int-array", 3,
+						   &val32));
+
+	ut_asserteq(5678, dev_read_u32_index_default(dev, "int-array", 0, 2));
+	ut_asserteq(9123, dev_read_u32_index_default(dev, "int-array", 1, 2));
+	ut_asserteq(4567, dev_read_u32_index_default(dev, "int-array", 2, 2));
+	ut_asserteq(2, dev_read_u32_index_default(dev, "int-array", 3, 2));
+
+	return 0;
+}
+DM_TEST(dm_test_read_int_index, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
 /* Test iteration through devices by drvdata */
 static int dm_test_uclass_drvdata(struct unit_test_state *uts)
 {