[PATCH 4/9] device property: provide fwnode_property_get_names()

[Bartosz Golaszewski]

Provide fwnode_property_get_names() - a new fwnode function that allows
callers to retrieve the list of all properties of given firmware node.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
 drivers/base/property.c  | 77 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/property.h |  1 +
 2 files changed, 78 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index a97575ff9199004b4f401f432aed6c95e40d0c25..7b0df3dfae53b6377dba91330aac746684e8adec 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -11,11 +11,13 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/export.h>
+#include <linux/minmax.h>
 #include <linux/of.h>
 #include <linux/property.h>
 #include <linux/phy.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/string_helpers.h>
 #include <linux/types.h>
 
 struct fwnode_handle *__dev_fwnode(struct device *dev)
@@ -542,6 +544,81 @@ int fwnode_property_match_string(const struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(fwnode_property_match_string);
 
+/**
+ * fwnode_property_get_names - get the list of all properties of this fwnode
+ * @fwnode: Firmware node to get the list of properties for
+ * @props: Pointer to an array of strings. It will contain the address of the
+ *	   string list containing the property names.
+ *
+ * Return: Number of property names written into *props. If > 0, the caller must
+ *	   free the array with kfree_strarray(). *props is only valid for
+ *	   a positive return value.
+ *	   %-EINVAL if arguments are not valid
+ *	   %-ENXIO if no suitable firmware interface is present
+ *	   %-ENOMEM if memory allocation failed
+ *
+ * The list also includes the properties of the secondary firmware node, if
+ * any. Properties present in both nodes are listed once.
+ */
+int fwnode_property_get_names(const struct fwnode_handle *fwnode, char ***props)
+{
+	int ret1, ret2 = -ENXIO, n1, n2, i, j, count;
+	char **prim = NULL, **sec = NULL, **merged;
+
+	if (IS_ERR_OR_NULL(fwnode))
+		return -EINVAL;
+
+	ret1 = fwnode_call_int_op(fwnode, property_get_names, &prim);
+	if (!IS_ERR_OR_NULL(fwnode->secondary))
+		ret2 = fwnode_call_int_op(fwnode->secondary, property_get_names, &sec);
+
+	if (ret1 == -ENXIO && ret2 == -ENXIO)
+		return -ENXIO;
+
+	n1 = max(ret1, 0);
+	n2 = max(ret2, 0);
+
+	CLASS(strarray, prim_props)(prim, n1);
+	CLASS(strarray, sec_props)(sec, n2);
+
+	if (ret1 < 0 && ret1 != -ENXIO)
+		return ret1;
+
+	if (ret2 < 0 && ret2 != -ENXIO)
+		return ret2;
+
+	if (n1 == 0 && n2 == 0)
+		return 0;
+
+	merged = kcalloc(n1 + n2, sizeof(*merged), GFP_KERNEL);
+	if (!merged)
+		return -ENOMEM;
+
+	/* The strings are now owned by merged, only free the container. */
+	for (i = 0; i < n1; i++) {
+		merged[i] = prim_props.array[i];
+		prim_props.array[i] = NULL;
+	}
+	count = n1;
+
+	/* Properties from the primary node take precedence. */
+	for (i = 0; i < n2; i++) {
+		for (j = 0; j < n1; j++) {
+			if (!strcmp(merged[j], sec_props.array[i]))
+				break;
+		}
+
+		if (j >= n1) {
+			merged[count++] = sec_props.array[i];
+			sec_props.array[i] = NULL;
+		}
+	}
+
+	*props = merged;
+	return count;
+}
+EXPORT_SYMBOL_GPL(fwnode_property_get_names);
+
 /**
  * fwnode_property_match_property_string - find a property string value in an array and return index
  * @fwnode: Firmware node to get the property of
diff --git a/include/linux/property.h b/include/linux/property.h
index 9143fe4f5c05179e595ba875aafbcb006a740824..a70f3c4c087dd85390951da950c3632f89c6cfd1 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -77,6 +77,7 @@ int fwnode_property_read_string(const struct fwnode_handle *fwnode,
 				const char *propname, const char **val);
 int fwnode_property_match_string(const struct fwnode_handle *fwnode,
 				 const char *propname, const char *string);
+int fwnode_property_get_names(const struct fwnode_handle *fwnode, char ***props);
 
 bool fwnode_device_is_available(const struct fwnode_handle *fwnode);
 

-- 
2.47.3