sh: extend clock struct with mapped_reg member

Add a "mapped_reg" member to struct clk and use that
to keep the ioremapped register based on enable_reg.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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)