clk: renesas: r8a7778: Obtain mode pin values using R-Car RST driver

Obtain the values of the mode pins from the R-Car RST driver, which
relies on the presence in DT of a device node for the RESET/WDT module.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>

drivers/clk/renesas/clk-r8a7778.c

@@ -12,6 +12,7 @@
 #include <linux/clk/renesas.h>
 #include <linux/of_address.h>
 #include <linux/slab.h>
+#include <linux/soc/renesas/rcar-rst.h>
 
 struct r8a7778_cpg {
 	struct clk_onecell_data data;
@@ -83,6 +84,18 @@ static void __init r8a7778_cpg_clocks_init(struct device_node *np)
 	struct clk **clks;
 	unsigned int i;
 	int num_clks;
+	u32 mode;
+
+	if (rcar_rst_read_mode_pins(&mode))
+		return;
+
+	BUG_ON(!(mode & BIT(19)));
+
+	cpg_mode_rates = (!!(mode & BIT(18)) << 2) |
+			 (!!(mode & BIT(12)) << 1) |
+			 (!!(mode & BIT(11)));
+	cpg_mode_divs = (!!(mode & BIT(2)) << 1) |
+			(!!(mode & BIT(1)));
 
 	num_clks = of_property_count_strings(np, "clock-output-names");
 	if (num_clks < 0) {