clk: ti: Add support for dm814x ADPLL

On dm814x we have 13 ADPLLs with 3 to 4 outputs on each. The
ADPLLs have several dividers and muxes controlled by a shared
control register for each PLL.

Note that for the clocks to work as device drivers for booting on
dm814x, this patch depends on "ARM: OMAP2+: Change core_initcall
levels to postcore_initcall" that has already been merged.

Also note that this patch does not implement clk_set_rate for the
PLL, that will be posted later on when available.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

Documentation/devicetree/bindings/clock/ti/adpll.txt

+Binding for Texas Instruments ADPLL clock.
+
+Binding status: Unstable - ABI compatibility may be broken in the future
+
+This binding uses the common clock binding[1]. It assumes a
+register-mapped ADPLL with two to three selectable input clocks
+and three to four children.
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be one of "ti,dm814-adpll-s-clock" or
+  "ti,dm814-adpll-lj-clock" depending on the type of the ADPLL
+- #clock-cells : from common clock binding; shall be set to 1.
+- clocks : link phandles of parent clocks clkinp and clkinpulow, note
+  that the adpll-s-clock also has an optional clkinphif
+- reg : address and length of the register set for controlling the ADPLL.
+
+Examples:
+	adpll_mpu_ck: adpll@40 {
+		#clock-cells = <1>;
+		compatible = "ti,dm814-adpll-s-clock";
+		reg = <0x40 0x40>;
+		clocks = <&devosc_ck &devosc_ck &devosc_ck>;
+		clock-names = "clkinp", "clkinpulow", "clkinphif";
+		clock-output-names = "481c5040.adpll.dcoclkldo",
+				     "481c5040.adpll.clkout",
+				     "481c5040.adpll.clkoutx2",
+				     "481c5040.adpll.clkouthif";
+	};
+
+	adpll_dsp_ck: adpll@80 {
+		#clock-cells = <1>;
+		compatible = "ti,dm814-adpll-lj-clock";
+		reg = <0x80 0x30>;
+		clocks = <&devosc_ck &devosc_ck>;
+		clock-names = "clkinp", "clkinpulow";
+		clock-output-names = "481c5080.adpll.dcoclkldo",
+				     "481c5080.adpll.clkout",
+				     "481c5080.adpll.clkoutldo";
+	};

drivers/clk/Kconfig

@@ -203,6 +203,7 @@ config COMMON_CLK_CDCE706
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/qcom/Kconfig"
+source "drivers/clk/ti/Kconfig"
 
 endmenu
 

drivers/clk/ti/Kconfig

+config COMMON_CLK_TI_ADPLL
+	tristate "Clock driver for dm814x ADPLL"
+	depends on ARCH_OMAP2PLUS || COMPILE_TEST
+	default y if SOC_TI81XX
+	---help---
+	  ADPLL clock driver for the dm814x SoC using common clock framework.

drivers/clk/ti/Makefile

@@ -18,3 +18,5 @@ obj-$(CONFIG_SOC_AM43XX)		+= $(clk-common) dpll3xxx.o clk-43xx.o
 ifdef CONFIG_ATAGS
 obj-$(CONFIG_ARCH_OMAP3)                += clk-3xxx-legacy.o
 endif
+
+obj-$(CONFIG_COMMON_CLK_TI_ADPLL)	+= adpll.o

drivers/clk/ti/clk-814x.c

@@ -5,8 +5,10 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/clk/ti.h>
+#include <linux/of_platform.h>
 
 #include "clock.h"
 
@@ -27,11 +29,62 @@ static struct ti_dt_clk dm814_clks[] = {
 	{ .node_name = NULL },
 };
 
+static bool timer_clocks_initialized;
+
+int __init dm814x_adpll_early_init(void)
+{
+	struct device_node *np;
+
+	if (!timer_clocks_initialized)
+		return -ENODEV;
+
+	np = of_find_node_by_name(NULL, "pllss");
+	if (!np) {
+		pr_err("Could not find node for plls\n");
+		return -ENODEV;
+	}
+
+	of_platform_populate(np, NULL, NULL, NULL);
+
+	return 0;
+}
+core_initcall(dm814x_adpll_early_init);
+
+static const char * const init_clocks[] = {
+	"pll040clkout",		/* MPU 481c5040.adpll.clkout */
+	"pll290clkout",		/* DDR 481c5290.adpll.clkout */
+};
+
+int __init dm814x_adpll_enable_init_clocks(void)
+{
+	int i, err;
+
+	if (!timer_clocks_initialized)
+		return -ENODEV;
+
+	for (i = 0; i < ARRAY_SIZE(init_clocks); i++) {
+		struct clk *clock;
+
+		clock = clk_get(NULL, init_clocks[i]);
+		if (WARN(IS_ERR(clock), "could not find init clock %s\n",
+			 init_clocks[i]))
+			continue;
+		err = clk_prepare_enable(clock);
+		if (WARN(err, "could not enable init clock %s\n",
+			 init_clocks[i]))
+			continue;
+	}
+
+	return 0;
+}
+postcore_initcall(dm814x_adpll_enable_init_clocks);
+
 int __init dm814x_dt_clk_init(void)
 {
 	ti_dt_clocks_register(dm814_clks);
 	omap2_clk_disable_autoidle_all();
 	omap2_clk_enable_init_clocks(NULL, 0);
+	timer_clocks_initialized = true;
 
 	return 0;
 }