clk: renesas: rcar-gen3: Add support for ZG clock

A clock used for the 3D graphics appears to be common
among multiple SoC's, so add a generic gen3 clock
for clocking the graphics.  This is similar to the
cpg_z_clk, with a different frequency control register
and different flags.  Instead of duplicating the code,
make cpg_z_clk_register into a helper function and
call the help function with the FCR and flags as
a parameter.

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230617150302.38477-1-aford173@gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: aford173

drivers/clk/renesas/rcar-gen3-cpg.c

@@ -264,11 +264,13 @@ static const struct clk_ops cpg_z_clk_ops = {
 	.set_rate = cpg_z_clk_set_rate,
 };
 
-static struct clk * __init cpg_z_clk_register(const char *name,
+static struct clk * __init __cpg_z_clk_register(const char *name,
 					      const char *parent_name,
 					      void __iomem *reg,
 					      unsigned int div,
-					      unsigned int offset)
+					      unsigned int offset,
+					      unsigned int fcr,
+					      unsigned int flags)
 {
 	struct clk_init_data init = {};
 	struct cpg_z_clk *zclk;
@@ -280,11 +282,11 @@ static struct clk * __init cpg_z_clk_register(const char *name,
 
 	init.name = name;
 	init.ops = &cpg_z_clk_ops;
-	init.flags = CLK_SET_RATE_PARENT;
+	init.flags = flags;
 	init.parent_names = &parent_name;
 	init.num_parents = 1;
 
-	zclk->reg = reg + CPG_FRQCRC;
+	zclk->reg = reg + fcr;
 	zclk->kick_reg = reg + CPG_FRQCRB;
 	zclk->hw.init = &init;
 	zclk->mask = GENMASK(offset + 4, offset);
@@ -301,6 +303,27 @@ static struct clk * __init cpg_z_clk_register(const char *name,
 	return clk;
 }
 
+static struct clk * __init cpg_z_clk_register(const char *name,
+					      const char *parent_name,
+					      void __iomem *reg,
+					      unsigned int div,
+					      unsigned int offset)
+{
+	return __cpg_z_clk_register(name, parent_name, reg, div, offset,
+				    CPG_FRQCRC, CLK_SET_RATE_PARENT);
+}
+
+static struct clk * __init cpg_zg_clk_register(const char *name,
+					       const char *parent_name,
+					       void __iomem *reg,
+					       unsigned int div,
+					       unsigned int offset)
+{
+	return __cpg_z_clk_register(name, parent_name, reg, div, offset,
+				    CPG_FRQCRB, 0);
+
+}
+
 static const struct clk_div_table cpg_rpcsrc_div_table[] = {
 	{ 2, 5 }, { 3, 6 }, { 0, 0 },
 };
@@ -438,6 +461,10 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 		return cpg_z_clk_register(core->name, __clk_get_name(parent),
 					  base, core->div, core->offset);
 
+	case CLK_TYPE_GEN3_ZG:
+		return cpg_zg_clk_register(core->name, __clk_get_name(parent),
+					   base, core->div, core->offset);
+
 	case CLK_TYPE_GEN3_OSC:
 		/*
 		 * Clock combining OSC EXTAL predivider and a fixed divider

drivers/clk/renesas/rcar-gen3-cpg.h

@@ -22,6 +22,7 @@ enum rcar_gen3_clk_types {
 	CLK_TYPE_GEN3_R,
 	CLK_TYPE_GEN3_MDSEL,	/* Select parent/divider using mode pin */
 	CLK_TYPE_GEN3_Z,
+	CLK_TYPE_GEN3_ZG,
 	CLK_TYPE_GEN3_OSC,	/* OSC EXTAL predivider and fixed divider */
 	CLK_TYPE_GEN3_RCKSEL,	/* Select parent/divider using RCKCR.CKSEL */
 	CLK_TYPE_GEN3_RPCSRC,