diff --git a/drivers/sh/clk/core.c b/drivers/sh/clk/core.c
index db257a3..7715de2 100644
--- a/drivers/sh/clk/core.c
+++ b/drivers/sh/clk/core.c
@@ -355,7 +355,7 @@
 		 */
 		if (!clk->parent) {
 			clk->mapping = &dummy_mapping;
-			return 0;
+			goto out;
 		}
 
 		/*
@@ -384,6 +384,9 @@
 	}
 
 	clk->mapping = mapping;
+out:
+	clk->mapped_reg = clk->mapping->base;
+	clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
 	return 0;
 }
 
@@ -402,10 +405,12 @@
 
 	/* Nothing to do */
 	if (mapping == &dummy_mapping)
-		return;
+		goto out;
 
 	kref_put(&mapping->ref, clk_destroy_mapping);
 	clk->mapping = NULL;
+out:
+	clk->mapped_reg = NULL;
 }
 
 int clk_register(struct clk *clk)
diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h
index e834304..54341d8 100644
--- a/include/linux/sh_clk.h
+++ b/include/linux/sh_clk.h
@@ -49,6 +49,7 @@
 
 	void __iomem		*enable_reg;
 	unsigned int		enable_bit;
+	void __iomem		*mapped_reg;
 
 	unsigned long		arch_flags;
 	void			*priv;