[RFC 1/3] clk: renesas: rcar-gen3: Add support for ZG clock

[Adam Ford <aford173@gmail.com>]

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.

Signed-off-by: Adam Ford <aford173@gmail.com>

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index b3ef62fa612e..7abfbf77a497 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -301,6 +301,39 @@ static struct clk * __init cpg_z_clk_register(const char *name,
 	return clk;
 }
 
+static struct clk * __init cpg_zg_clk_register(const char *name,
+					       const char *parent_name,
+					       void __iomem *reg,
+					       unsigned int div,
+					       unsigned int offset)
+{
+	struct clk_init_data init;
+	struct cpg_z_clk *zclk;
+	struct clk *clk;
+
+	zclk = kzalloc(sizeof(*zclk), GFP_KERNEL);
+	if (!zclk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &cpg_z_clk_ops;
+	init.flags = 0;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	zclk->reg = reg + CPG_FRQCRB;
+	zclk->kick_reg = reg + CPG_FRQCRB;
+	zclk->hw.init = &init;
+	zclk->mask = GENMASK(offset + 4, offset);
+	zclk->fixed_div = div; /* PLLVCO x 1/div1 x 3DGE divider x 1/div2 */
+
+	clk = clk_register(NULL, &zclk->hw);
+	if (IS_ERR(clk))
+		kfree(zclk);
+
+	return clk;
+}
+
 static const struct clk_div_table cpg_rpcsrc_div_table[] = {
 	{ 2, 5 }, { 3, 6 }, { 0, 0 },
 };
@@ -502,6 +535,9 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 	case CLK_TYPE_GEN3_RPCD2:
 		return cpg_rpcd2_clk_register(core->name, base + CPG_RPCCKCR,
 					      __clk_get_name(parent));
+	case CLK_TYPE_GEN3_ZG:
+		return cpg_zg_clk_register(core->name, __clk_get_name(parent),
+					   base, core->div, core->offset);
 
 	default:
 		return ERR_PTR(-EINVAL);
diff --git a/drivers/clk/renesas/rcar-gen3-cpg.h b/drivers/clk/renesas/rcar-gen3-cpg.h
index 9028bf4295ce..bfdc649bdf12 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.h
+++ b/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,
-- 
2.39.2