clk: rockchip: add support for half divider

The new Rockchip socs have optional half divider:
The formula is shown as:
	freq_out = 2*freq_in / (2*div + 3)
Is this the same for all of new SoCs.

So we use "branch_half_divider" + "COMPOSITE_NOMUX_HALFDIV \
DIV_HALF \ COMPOSITE_HALFDIV \ CMPOSITE_NOGATE_HALFDIV"
to hook that special divider clock-type into our clock-tree.

Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk.h

@@ -354,6 +354,7 @@ enum rockchip_clk_branch_type {
 	branch_inverter,
 	branch_factor,
 	branch_ddrclk,
+	branch_half_divider,
 };
 
 struct rockchip_clk_branch {
@@ -684,6 +685,79 @@ struct rockchip_clk_branch {
 		.gate_flags	= gf,				\
 	}
 
+#define COMPOSITE_HALFDIV(_id, cname, pnames, f, mo, ms, mw, mf, ds, dw,\
+			  df, go, gs, gf)				\
+	{							\
+		.id		= _id,				\
+		.branch_type	= branch_half_divider,		\
+		.name		= cname,			\
+		.parent_names	= pnames,			\
+		.num_parents	= ARRAY_SIZE(pnames),		\
+		.flags		= f,				\
+		.muxdiv_offset	= mo,				\
+		.mux_shift	= ms,				\
+		.mux_width	= mw,				\
+		.mux_flags	= mf,				\
+		.div_shift	= ds,				\
+		.div_width	= dw,				\
+		.div_flags	= df,				\
+		.gate_offset	= go,				\
+		.gate_shift	= gs,				\
+		.gate_flags	= gf,				\
+	}
+
+#define COMPOSITE_NOGATE_HALFDIV(_id, cname, pnames, f, mo, ms, mw, mf,	\
+				 ds, dw, df)				\
+	{							\
+		.id		= _id,				\
+		.branch_type	= branch_half_divider,		\
+		.name		= cname,			\
+		.parent_names	= pnames,			\
+		.num_parents	= ARRAY_SIZE(pnames),		\
+		.flags		= f,				\
+		.muxdiv_offset	= mo,				\
+		.mux_shift	= ms,				\
+		.mux_width	= mw,				\
+		.mux_flags	= mf,				\
+		.div_shift	= ds,				\
+		.div_width	= dw,				\
+		.div_flags	= df,				\
+		.gate_offset	= -1,				\
+	}
+
+#define COMPOSITE_NOMUX_HALFDIV(_id, cname, pname, f, mo, ds, dw, df,	\
+			go, gs, gf)				\
+	{							\
+		.id		= _id,				\
+		.branch_type	= branch_half_divider,		\
+		.name		= cname,			\
+		.parent_names	= (const char *[]){ pname },	\
+		.num_parents	= 1,				\
+		.flags		= f,				\
+		.muxdiv_offset	= mo,				\
+		.div_shift	= ds,				\
+		.div_width	= dw,				\
+		.div_flags	= df,				\
+		.gate_offset	= go,				\
+		.gate_shift	= gs,				\
+		.gate_flags	= gf,				\
+	}
+
+#define DIV_HALF(_id, cname, pname, f, o, s, w, df)			\
+	{							\
+		.id		= _id,				\
+		.branch_type	= branch_half_divider,		\
+		.name		= cname,			\
+		.parent_names	= (const char *[]){ pname },	\
+		.num_parents	= 1,				\
+		.flags		= f,				\
+		.muxdiv_offset	= o,				\
+		.div_shift	= s,				\
+		.div_width	= w,				\
+		.div_flags	= df,				\
+		.gate_offset	= -1,				\
+	}
+
 struct rockchip_clk_provider *rockchip_clk_init(struct device_node *np,
 			void __iomem *base, unsigned long nr_clks);
 void rockchip_clk_of_add_provider(struct device_node *np,
@@ -708,6 +782,17 @@ void rockchip_register_restart_notifier(struct rockchip_clk_provider *ctx,
 
 #define ROCKCHIP_SOFTRST_HIWORD_MASK	BIT(0)
 
+struct clk *rockchip_clk_register_halfdiv(const char *name,
+					  const char *const *parent_names,
+					  u8 num_parents, void __iomem *base,
+					  int muxdiv_offset, u8 mux_shift,
+					  u8 mux_width, u8 mux_flags,
+					  u8 div_shift, u8 div_width,
+					  u8 div_flags, int gate_offset,
+					  u8 gate_shift, u8 gate_flags,
+					  unsigned long flags,
+					  spinlock_t *lock);
+
 #ifdef CONFIG_RESET_CONTROLLER
 void rockchip_register_softrst(struct device_node *np,
 			       unsigned int num_regs,