dm: core: Add a function to look up a uclass by name

Each uclass has a driver name which we can use to look up the uclass. This
is useful for logging, where the uclass ID is used as the category.

Add a function to handle this, as well as a test.

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

drivers/core/uclass.c

@@ -158,6 +158,20 @@ const char *uclass_get_name(enum uclass_id id)
 	return uc->uc_drv->name;
 }
 
+enum uclass_id uclass_get_by_name(const char *name)
+{
+	int i;
+
+	for (i = 0; i < UCLASS_COUNT; i++) {
+		struct uclass_driver *uc_drv = lists_uclass_lookup(i);
+
+		if (uc_drv && !strcmp(uc_drv->name, name))
+			return i;
+	}
+
+	return UCLASS_INVALID;
+}
+
 int uclass_find_device(enum uclass_id id, int index, struct udevice **devp)
 {
 	struct uclass *uc;

include/dm/uclass.h

@@ -128,6 +128,14 @@ int uclass_get(enum uclass_id key, struct uclass **ucp);
 const char *uclass_get_name(enum uclass_id id);
 
 /**
+ * uclass_get_by_name() - Look up a uclass by its driver name
+ *
+ * @name: Name to look up
+ * @returns the associated uclass ID, or UCLASS_INVALID if not found
+ */
+enum uclass_id uclass_get_by_name(const char *name);
+
+/**
  * uclass_get_device() - Get a uclass device based on an ID and index
  *
  * The device is probed to activate it ready for use.

test/dm/core.c

@@ -862,3 +862,12 @@ static int dm_test_device_get_uclass_id(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_device_get_uclass_id, DM_TESTF_SCAN_PDATA);
+
+static int dm_test_uclass_names(struct unit_test_state *uts)
+{
+	ut_asserteq_str("test", uclass_get_name(UCLASS_TEST));
+	ut_asserteq(UCLASS_TEST, uclass_get_by_name("test"));
+
+	return 0;
+}
+DM_TEST(dm_test_uclass_names, DM_TESTF_SCAN_PDATA);