[PATCHv10 01/41] clk: add support for platform specific clock I/O wrapper functions

[Tero Kristo]

Current clock wrappers assume simple and direct mapped hardware register
access. Improve this support by adding functionality for registering
platform specific clock I/O wrappers, which can be used to support
various features needed like endianess conversions, indexed regmap support,
etc. Default I/O wrapper provided also which uses the existing direct
I/O mapped behavior.

Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
 drivers/clk/clk.c            |   68 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/clk-provider.h |   15 +++++-----
 2 files changed, 75 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 2cf2ea6..c331386 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -34,6 +34,74 @@ static HLIST_HEAD(clk_root_list);
 static HLIST_HEAD(clk_orphan_list);
 static LIST_HEAD(clk_notifier_list);
 
+/**
+ * clk_readl_default - default clock register read support function
+ * @reg: register to read
+ *
+ * Default implementation for reading a clock register.
+ */
+static u32 clk_readl_default(u32 __iomem *reg)
+{
+	return readl(reg);
+}
+
+/**
+ * clk_writel_default - default clock register write support function
+ * @val: value to write
+ * @reg: register to write to
+ *
+ * Default implementation for writing a clock register.
+ */
+static void clk_writel_default(u32 val, u32 __iomem *reg)
+{
+	writel(val, reg);
+}
+
+struct clk_reg_ops clk_reg_ops_default = {
+	.clk_readl = clk_readl_default,
+	.clk_writel = clk_writel_default
+};
+
+static struct clk_reg_ops *clk_reg_ops = &clk_reg_ops_default;
+
+/**
+ * clk_register_reg_ops - register access functions for clock registers
+ * @ops: register level ops
+ *
+ * Registers platform or SoC specific operations for reading / writing
+ * clock registers.
+ */
+int clk_register_reg_ops(struct clk_reg_ops *ops)
+{
+	if (!ops)
+		return -EINVAL;
+	clk_reg_ops = ops;
+	return 0;
+}
+
+/**
+ * clk_readl - read a clock register value from hardware
+ * @reg: register to read
+ *
+ * Uses the registered clk_reg_ops to read a hardware clock register value.
+ */
+u32 clk_readl(u32 __iomem *reg)
+{
+	return clk_reg_ops->clk_readl(reg);
+}
+
+/**
+ * clk_writel - write a clock register value to hardware
+ * @val: value to write
+ * @reg: register to write
+ *
+ * Uses the registered clk_reg_ops to write a hardware clock register value.
+ */
+void clk_writel(u32 val, u32 __iomem *reg)
+{
+	clk_reg_ops->clk_writel(val, reg);
+}
+
 /***           locking             ***/
 static void clk_prepare_lock(void)
 {
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7e59253..16e4df2 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -512,15 +512,14 @@ static inline const char *of_clk_get_parent_name(struct device_node *np,
  * for improved portability across platforms
  */
 
-static inline u32 clk_readl(u32 __iomem *reg)
-{
-	return readl(reg);
-}
+struct clk_reg_ops {
+	u32 (*clk_readl)(u32 __iomem *reg);
+	void (*clk_writel)(u32 val, u32 __iomem *reg);
+};
 
-static inline void clk_writel(u32 val, u32 __iomem *reg)
-{
-	writel(val, reg);
-}
+u32 clk_readl(u32 __iomem *reg);
+void clk_writel(u32 val, u32 __iomem *reg);
+int clk_register_reg_ops(struct clk_reg_ops *ops);
 
 #endif /* CONFIG_COMMON_CLK */
 #endif /* CLK_PROVIDER_H */
-- 
1.7.9.5