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>

drivers/clk/clk-divider.c

@@ -104,7 +104,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int div, val;
 
-	val = readl(divider->reg) >> divider->shift;
+	val = clk_readl(divider->reg) >> divider->shift;
 	val &= div_mask(divider);
 
 	div = _get_div(divider, val);
@@ -230,11 +230,11 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 		val = div_mask(divider) << (divider->shift + 16);
 	} else {
-		val = readl(divider->reg);
+		val = clk_readl(divider->reg);
 		val &= ~(div_mask(divider) << divider->shift);
 	}
 	val |= value << divider->shift;
-	writel(val, divider->reg);
+	clk_writel(val, divider->reg);
 
 	if (divider->lock)
 		spin_unlock_irqrestore(divider->lock, flags);

drivers/clk/clk-gate.c

@@ -58,7 +58,7 @@ static void clk_gate_endisable(struct clk_hw *hw, int enable)
 		if (set)
 			reg |= BIT(gate->bit_idx);
 	} else {
-		reg = readl(gate->reg);
+		reg = clk_readl(gate->reg);
 
 		if (set)
 			reg |= BIT(gate->bit_idx);
@@ -66,7 +66,7 @@ static void clk_gate_endisable(struct clk_hw *hw, int enable)
 			reg &= ~BIT(gate->bit_idx);
 	}
 
-	writel(reg, gate->reg);
+	clk_writel(reg, gate->reg);
 
 	if (gate->lock)
 		spin_unlock_irqrestore(gate->lock, flags);
@@ -89,7 +89,7 @@ static int clk_gate_is_enabled(struct clk_hw *hw)
 	u32 reg;
 	struct clk_gate *gate = to_clk_gate(hw);
 
-	reg = readl(gate->reg);
+	reg = clk_readl(gate->reg);
 
 	/* if a set bit disables this clk, flip it before masking */
 	if (gate->flags & CLK_GATE_SET_TO_DISABLE)

drivers/clk/clk-mux.c

@@ -42,7 +42,7 @@ static u8 clk_mux_get_parent(struct clk_hw *hw)
 	 * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
 	 * val = 0x4 really means "bit 2, index starts at bit 0"
 	 */
-	val = readl(mux->reg) >> mux->shift;
+	val = clk_readl(mux->reg) >> mux->shift;
 	val &= mux->mask;
 
 	if (mux->table) {
@@ -89,11 +89,11 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
 	if (mux->flags & CLK_MUX_HIWORD_MASK) {
 		val = mux->mask << (mux->shift + 16);
 	} else {
-		val = readl(mux->reg);
+		val = clk_readl(mux->reg);
 		val &= ~(mux->mask << mux->shift);
 	}
 	val |= index << mux->shift;
-	writel(val, mux->reg);
+	clk_writel(val, mux->reg);
 
 	if (mux->lock)
 		spin_unlock_irqrestore(mux->lock, flags);

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 */