diff --git a/drivers/pnp/base.h b/drivers/pnp/base.h
index 0bab84e..19bc736 100644
--- a/drivers/pnp/base.h
+++ b/drivers/pnp/base.h
@@ -12,11 +12,12 @@
 
 #define PNP_EISA_ID_MASK 0x7fffffff
 void pnp_eisa_id_to_string(u32 id, char *str);
-struct pnp_dev *pnp_alloc_dev(struct pnp_protocol *, int id, char *pnpid);
+struct pnp_dev *pnp_alloc_dev(struct pnp_protocol *, int id,
+			      const char *pnpid);
 struct pnp_card *pnp_alloc_card(struct pnp_protocol *, int id, char *pnpid);
 
 int pnp_add_device(struct pnp_dev *dev);
-struct pnp_id *pnp_add_id(struct pnp_dev *dev, char *id);
+struct pnp_id *pnp_add_id(struct pnp_dev *dev, const char *id);
 
 int pnp_add_card(struct pnp_card *card);
 void pnp_remove_card(struct pnp_card *card);