1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/pnp/isapnp/compat.c b/drivers/pnp/isapnp/compat.c
new file mode 100644
index 0000000000..d60d9e377d
--- /dev/null
+++ b/drivers/pnp/isapnp/compat.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * compat.c - A series of functions to make it easier to convert drivers that use
+ *            the old isapnp APIs. If possible use the new APIs instead.
+ *
+ * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
+ */
+
+#include <linux/module.h>
+#include <linux/isapnp.h>
+#include <linux/string.h>
+
+static void pnp_convert_id(char *buf, unsigned short vendor,
+			   unsigned short device)
+{
+	sprintf(buf, "%c%c%c%x%x%x%x",
+		'A' + ((vendor >> 2) & 0x3f) - 1,
+		'A' + (((vendor & 3) << 3) | ((vendor >> 13) & 7)) - 1,
+		'A' + ((vendor >> 8) & 0x1f) - 1,
+		(device >> 4) & 0x0f, device & 0x0f,
+		(device >> 12) & 0x0f, (device >> 8) & 0x0f);
+}
+
+struct pnp_dev *pnp_find_dev(struct pnp_card *card, unsigned short vendor,
+			     unsigned short function, struct pnp_dev *from)
+{
+	char id[8];
+	char any[8];
+
+	pnp_convert_id(id, vendor, function);
+	pnp_convert_id(any, ISAPNP_ANY_ID, ISAPNP_ANY_ID);
+	if (card == NULL) {	/* look for a logical device from all cards */
+		struct list_head *list;
+
+		list = pnp_global.next;
+		if (from)
+			list = from->global_list.next;
+
+		while (list != &pnp_global) {
+			struct pnp_dev *dev = global_to_pnp_dev(list);
+
+			if (compare_pnp_id(dev->id, id) ||
+			    (memcmp(id, any, 7) == 0))
+				return dev;
+			list = list->next;
+		}
+	} else {
+		struct list_head *list;
+
+		list = card->devices.next;
+		if (from) {
+			list = from->card_list.next;
+			if (from->card != card)	/* something is wrong */
+				return NULL;
+		}
+		while (list != &card->devices) {
+			struct pnp_dev *dev = card_to_pnp_dev(list);
+
+			if (compare_pnp_id(dev->id, id))
+				return dev;
+			list = list->next;
+		}
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(pnp_find_dev);