clk: renesas: r8a774c0: Add RPC clocks

Describe the RPCSRC internal clock and the RPC[D2] clocks derived from it,
as well as the RPC-IF module clock, in the RZ/G2E (R8A774C0) CPG/MSSR
driver.

Add new clk type CLK_TYPE_GEN3_E3_RPCSRC to register rpcsrc as a fixed
clock on R-Car Gen3 E3 (and also RZ/G2E which is identical to E3 SoC),
parent and the divider is set based on the register value CPG_RPCCKCR[4:3]
which has been set prior to booting the kernel.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20201116101002.5986-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index a7debddf7d09..063b61151488 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -695,6 +695,34 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev,
 						  cpg_rpcsrc_div_table,
 						  &cpg_lock);
 
+	case CLK_TYPE_GEN3_E3_RPCSRC:
+		/*
+		 * Register RPCSRC as fixed factor clock based on the
+		 * MD[4:1] pins and CPG_RPCCKCR[4:3] register value for
+		 * which has been set prior to booting the kernel.
+		 */
+		value = (readl(base + CPG_RPCCKCR) & GENMASK(4, 3)) >> 3;
+
+		switch (value) {
+		case 0:
+			div = 5;
+			break;
+		case 1:
+			div = 3;
+			break;
+		case 2:
+			parent = clks[core->parent >> 16];
+			if (IS_ERR(parent))
+				return ERR_CAST(parent);
+			div = core->div;
+			break;
+		case 3:
+		default:
+			div = 2;
+			break;
+		}
+		break;
+
 	case CLK_TYPE_GEN3_RPC:
 		return cpg_rpc_clk_register(core->name, base,
 					    __clk_get_name(parent), notifiers);