clk: renesas: rcar-gen3: Add support for SCCG/Clean peripheral clocks

On R-Car Gen3 SoCs with a Spread Spectrum Clock Generator (e.g. R-Car
D3), a peripheral clock divider has been added, to select between clean
and spread spectrum parents.

Add a new clock type to the R-Car Gen3 driver core to handle this.
To avoid increasing the size of struct cpg_core_clk, both parents and
dividers are stored in the existing parent resp. div fields.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>

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

@@ -272,7 +272,7 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 	unsigned int div = 1;
 	u32 value;
 
-	parent = clks[core->parent];
+	parent = clks[core->parent & 0xffff];	/* CLK_TYPE_PE uses high bits */
 	if (IS_ERR(parent))
 		return ERR_CAST(parent);
 
@@ -355,6 +355,24 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 			parent = clks[cpg_clk_extalr];
 		break;
 
+	case CLK_TYPE_GEN3_PE:
+		/*
+		 * Peripheral clock with a fixed divider, selectable between
+		 * clean and spread spectrum parents using MD12
+		 */
+		if (cpg_mode & BIT(12)) {
+			/* Clean */
+			div = core->div & 0xffff;
+		} else {
+			/* SCCG */
+			parent = clks[core->parent >> 16];
+			if (IS_ERR(parent))
+				return ERR_CAST(parent);
+			div = core->div >> 16;
+		}
+		mult = 1;
+		break;
+
 	default:
 		return ERR_PTR(-EINVAL);
 	}

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

@@ -20,11 +20,18 @@ enum rcar_gen3_clk_types {
 	CLK_TYPE_GEN3_PLL4,
 	CLK_TYPE_GEN3_SD,
 	CLK_TYPE_GEN3_R,
+	CLK_TYPE_GEN3_PE,
 };
 
 #define DEF_GEN3_SD(_name, _id, _parent, _offset)	\
 	DEF_BASE(_name, _id, CLK_TYPE_GEN3_SD, _parent, .offset = _offset)
 
+#define DEF_GEN3_PE(_name, _id, _parent_sscg, _div_sscg, _parent_clean, \
+		    _div_clean) \
+	DEF_BASE(_name, _id, CLK_TYPE_GEN3_PE,			\
+		 (_parent_sscg) << 16 | (_parent_clean),	\
+		 .div = (_div_sscg) << 16 | (_div_clean))
+
 struct rcar_gen3_cpg_pll_config {
 	u8 extal_div;
 	u8 pll1_mult;