clk: renesas: r8a7790: Add new CPG/MSSR driver

Add a new R-Car H2 Clock Pulse Generator / Module Standby and Software
Reset driver, using the CPG/MSSR driver core.  This will enable support
for module resets, which are not supported by the existing driver.

The old driver can still be used through a Kconfig option, to preserve
backward compatibility with old DTBs.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/clk/renesas/Kconfig

@@ -19,6 +19,16 @@ config CLK_RENESAS
 
 if CLK_RENESAS
 
+config CLK_RENESAS_LEGACY
+	bool "Legacy DT clock support"
+	depends on CLK_R8A7790
+	default y
+	help
+	  Enable backward compatibility with old device trees describing a
+	  hierarchical representation of the various CPG and MSTP clocks.
+
+	  Say Y if you want your kernel to work with old DTBs.
+
 # SoC
 config CLK_EMEV2
 	bool "Emma Mobile EV2 clock support" if COMPILE_TEST
@@ -55,7 +65,8 @@ config CLK_R8A7779
 
 config CLK_R8A7790
 	bool
-	select CLK_RCAR_GEN2
+	select CLK_RCAR_GEN2 if CLK_RENESAS_LEGACY
+	select CLK_RCAR_GEN2_CPG
 	select CLK_RENESAS_DIV6
 
 config CLK_R8A7791

drivers/clk/renesas/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_CLK_R8A7743)		+= r8a7743-cpg-mssr.o
 obj-$(CONFIG_CLK_R8A7745)		+= r8a7745-cpg-mssr.o
 obj-$(CONFIG_CLK_R8A7778)		+= clk-r8a7778.o
 obj-$(CONFIG_CLK_R8A7779)		+= clk-r8a7779.o
+obj-$(CONFIG_CLK_R8A7790)		+= r8a7790-cpg-mssr.o
 obj-$(CONFIG_CLK_R8A7795)		+= r8a7795-cpg-mssr.o
 obj-$(CONFIG_CLK_R8A7796)		+= r8a7796-cpg-mssr.o
 obj-$(CONFIG_CLK_SH73A0)		+= clk-sh73a0.o

drivers/clk/renesas/renesas-cpg-mssr.c

@@ -639,6 +639,12 @@ static const struct of_device_id cpg_mssr_match[] = {
 		.data = &r8a7745_cpg_mssr_info,
 	},
 #endif
+#ifdef CONFIG_CLK_R8A7790
+	{
+		.compatible = "renesas,r8a7790-cpg-mssr",
+		.data = &r8a7790_cpg_mssr_info,
+	},
+#endif
 #ifdef CONFIG_CLK_R8A7795
 	{
 		.compatible = "renesas,r8a7795-cpg-mssr",

drivers/clk/renesas/renesas-cpg-mssr.h

@@ -132,6 +132,7 @@ struct cpg_mssr_info {
 
 extern const struct cpg_mssr_info r8a7743_cpg_mssr_info;
 extern const struct cpg_mssr_info r8a7745_cpg_mssr_info;
+extern const struct cpg_mssr_info r8a7790_cpg_mssr_info;
 extern const struct cpg_mssr_info r8a7795_cpg_mssr_info;
 extern const struct cpg_mssr_info r8a7796_cpg_mssr_info;