of: Add of_property_match_string() to find index into a string list

Add a helper function for finding the index of a string in a string list property. This helper is useful for bindings that use a separate *-name property for attaching names to tuples in another property such as 'reg' or 'gpios'. Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

of: Add of_property_match_string() to find index into a string list
Add a helper function for finding the index of a string in a string list property. This helper is useful for bindings that use a separate *-name property for attaching names to tuples in another property such as 'reg' or 'gpios'. Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Grant Likely
1 parent dcd6c92267
Showing 4 changed files with 70 additions and 0 deletions Side-by-side Diff
arch/arm/boot/dts/testcases/tests-phandle.dtsi
drivers/of/base.c
drivers/of/selftest.c
include/linux/of.h
@@ -31,6 +31,8 @@
 				phandle-list-bad-phandle = <12345678 0 0>;
 				phandle-list-bad-args = <&provider2 1 0>,
 							<&provider3 0>;
+				empty-property;
+				unterminated-string = [40 41 42 43];
 			};
 		};
 	};
@@ -761,6 +761,42 @@
 }
 EXPORT_SYMBOL_GPL(of_property_read_string_index);
  
+/**
+ * of_property_match_string() - Find string in a list and return index
+ * @np: pointer to node containing string list property
+ * @propname: string list property name
+ * @string: pointer to string to search for in string list
+ *
+ * This function searches a string list property and returns the index
+ * of a specific string value.
+ */
+int of_property_match_string(struct device_node *np, const char *propname,
+			     const char *string)
+{
+	struct property *prop = of_find_property(np, propname, NULL);
+	size_t l;
+	int i;
+	const char *p, *end;
+
+	if (!prop)
+		return -EINVAL;
+	if (!prop->value)
+		return -ENODATA;
+
+	p = prop->value;
+	end = p + prop->length;
+
+	for (i = 0; p < end; i++, p += l) {
+		l = strlen(p) + 1;
+		if (p + l > end)
+			return -EILSEQ;
+		pr_debug("comparing %s with %s\n", string, p);
+		if (strcmp(string, p) == 0)
+			return i; /* Found it; return index */
+	}
+	return -ENODATA;
+}
+EXPORT_SYMBOL_GPL(of_property_match_string);
  
 /**
  * of_property_count_strings - Find and return the number of strings from a
@@ -120,6 +120,34 @@
 	pr_info("end - %s\n", passed_all ? "PASS" : "FAIL");
 }
  
+static void __init of_selftest_property_match_string(void)
+{
+	struct device_node *np;
+	int rc;
+
+	pr_info("start\n");
+	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
+	if (!np) {
+		pr_err("No testcase data in device tree\n");
+		return;
+	}
+
+	rc = of_property_match_string(np, "phandle-list-names", "first");
+	selftest(rc == 0, "first expected:0 got:%i\n", rc);
+	rc = of_property_match_string(np, "phandle-list-names", "second");
+	selftest(rc == 1, "second expected:0 got:%i\n", rc);
+	rc = of_property_match_string(np, "phandle-list-names", "third");
+	selftest(rc == 2, "third expected:0 got:%i\n", rc);
+	rc = of_property_match_string(np, "phandle-list-names", "fourth");
+	selftest(rc == -ENODATA, "unmatched string; rc=%i", rc);
+	rc = of_property_match_string(np, "missing-property", "blah");
+	selftest(rc == -EINVAL, "missing property; rc=%i", rc);
+	rc = of_property_match_string(np, "empty-property", "blah");
+	selftest(rc == -ENODATA, "empty property; rc=%i", rc);
+	rc = of_property_match_string(np, "unterminated-string", "blah");
+	selftest(rc == -EILSEQ, "unterminated string; rc=%i", rc);
+}
+
 static int __init of_selftest(void)
 {
 	struct device_node *np;
@@ -133,6 +161,7 @@
  
 	pr_info("start of selftest - you will see error messages\n");
 	of_selftest_parse_phandle_with_args();
+	of_selftest_property_match_string();
 	pr_info("end of selftest - %s\n", selftest_passed ? "PASS" : "FAIL");
 	return 0;
 }
@@ -217,6 +217,9 @@
 extern int of_property_read_string_index(struct device_node *np,
 					 const char *propname,
 					 int index, const char **output);
+extern int of_property_match_string(struct device_node *np,
+				    const char *propname,
+				    const char *string);
 extern int of_property_count_strings(struct device_node *np,
 				     const char *propname);
 extern int of_device_is_compatible(const struct device_node *device,
...	...	@@ -31,6 +31,8 @@
31	31	phandle-list-bad-phandle = <12345678 0 0>;
32	32	phandle-list-bad-args = <&provider2 1 0>,
33	33	<&provider3 0>;
	34	+ empty-property;
	35	+ unterminated-string = [40 41 42 43];
34	36	};
35	37	};
36	38	};
...	...	@@ -761,6 +761,42 @@
761	761	}
762	762	EXPORT_SYMBOL_GPL(of_property_read_string_index);
763	763
	764	+/**
	765	+ * of_property_match_string() - Find string in a list and return index
	766	+ * @np: pointer to node containing string list property
	767	+ * @propname: string list property name
	768	+ * @string: pointer to string to search for in string list
	769	+ *
	770	+ * This function searches a string list property and returns the index
	771	+ * of a specific string value.
	772	+ */
	773	+int of_property_match_string(struct device_node np, const char propname,
	774	+ const char *string)
	775	+{
	776	+ struct property *prop = of_find_property(np, propname, NULL);
	777	+ size_t l;
	778	+ int i;
	779	+ const char p, end;
	780	+
	781	+ if (!prop)
	782	+ return -EINVAL;
	783	+ if (!prop->value)
	784	+ return -ENODATA;
	785	+
	786	+ p = prop->value;
	787	+ end = p + prop->length;
	788	+
	789	+ for (i = 0; p < end; i++, p += l) {
	790	+ l = strlen(p) + 1;
	791	+ if (p + l > end)
	792	+ return -EILSEQ;
	793	+ pr_debug("comparing %s with %s\n", string, p);
	794	+ if (strcmp(string, p) == 0)
	795	+ return i; /* Found it; return index */
	796	+ }
	797	+ return -ENODATA;
	798	+}
	799	+EXPORT_SYMBOL_GPL(of_property_match_string);
764	800
765	801	/**
766	802	* of_property_count_strings - Find and return the number of strings from a
...	...	@@ -120,6 +120,34 @@
120	120	pr_info("end - %s\n", passed_all ? "PASS" : "FAIL");
121	121	}
122	122
	123	+static void __init of_selftest_property_match_string(void)
	124	+{
	125	+ struct device_node *np;
	126	+ int rc;
	127	+
	128	+ pr_info("start\n");
	129	+ np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
	130	+ if (!np) {
	131	+ pr_err("No testcase data in device tree\n");
	132	+ return;
	133	+ }
	134	+
	135	+ rc = of_property_match_string(np, "phandle-list-names", "first");
	136	+ selftest(rc == 0, "first expected:0 got:%i\n", rc);
	137	+ rc = of_property_match_string(np, "phandle-list-names", "second");
	138	+ selftest(rc == 1, "second expected:0 got:%i\n", rc);
	139	+ rc = of_property_match_string(np, "phandle-list-names", "third");
	140	+ selftest(rc == 2, "third expected:0 got:%i\n", rc);
	141	+ rc = of_property_match_string(np, "phandle-list-names", "fourth");
	142	+ selftest(rc == -ENODATA, "unmatched string; rc=%i", rc);
	143	+ rc = of_property_match_string(np, "missing-property", "blah");
	144	+ selftest(rc == -EINVAL, "missing property; rc=%i", rc);
	145	+ rc = of_property_match_string(np, "empty-property", "blah");
	146	+ selftest(rc == -ENODATA, "empty property; rc=%i", rc);
	147	+ rc = of_property_match_string(np, "unterminated-string", "blah");
	148	+ selftest(rc == -EILSEQ, "unterminated string; rc=%i", rc);
	149	+}
	150	+
123	151	static int __init of_selftest(void)
124	152	{
125	153	struct device_node *np;
...	...	@@ -133,6 +161,7 @@
133	161
134	162	pr_info("start of selftest - you will see error messages\n");
135	163	of_selftest_parse_phandle_with_args();
	164	+ of_selftest_property_match_string();
136	165	pr_info("end of selftest - %s\n", selftest_passed ? "PASS" : "FAIL");
137	166	return 0;
138	167	}
...	...	@@ -217,6 +217,9 @@
217	217	extern int of_property_read_string_index(struct device_node *np,
218	218	const char *propname,
219	219	int index, const char **output);
	220	+extern int of_property_match_string(struct device_node *np,
	221	+ const char *propname,
	222	+ const char *string);
220	223	extern int of_property_count_strings(struct device_node *np,
221	224	const char *propname);
222	225	extern int of_device_is_compatible(const struct device_node *device,