clk: wrap I/O access for improved portability

the common clock drivers were motivated/initiated by ARM development
and apparently assume little endian peripherals

wrap register/peripherals access in the common code (div, gate, mux)
in preparation of adding COMMON_CLK support for other platforms

Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

include/linux/clk-provider.h

@@ -12,6 +12,7 @@
 #define __LINUX_CLK_PROVIDER_H
 
 #include <linux/clk.h>
+#include <linux/io.h>
 
 #ifdef CONFIG_COMMON_CLK
 
@@ -504,5 +505,21 @@ static inline const char *of_clk_get_parent_name(struct device_node *np,
 #define of_clk_init(matches) \
 	{ while (0); }
 #endif /* CONFIG_OF */
+
+/*
+ * wrap access to peripherals in accessor routines
+ * for improved portability across platforms
+ */
+
+static inline u32 clk_readl(u32 __iomem *reg)
+{
+	return readl(reg);
+}
+
+static inline void clk_writel(u32 val, u32 __iomem *reg)
+{
+	writel(val, reg);
+}
+
 #endif /* CONFIG_COMMON_CLK */
 #endif /* CLK_PROVIDER_H */