clk: Common clocks implementation for Versatile Express

This patch adds a DT and non-DT based implementation of
the common clock infrastructure for Versatile Express
platform. It registers (statically or using DT) all
required fixed clocks, initialises motherboard's SP810
cell (that provides clocks for SP804 timers) and
explicitly registers VE "osc" driver, to make the
clock generators available early.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

arch/arm/include/asm/hardware/sp810.h

@@ -56,6 +56,8 @@
 #define SCCTRL_TIMEREN1SEL_REFCLK	(0 << 17)
 #define SCCTRL_TIMEREN1SEL_TIMCLK	(1 << 17)
 
+#define SCCTRL_TIMERENnSEL_SHIFT(n)	(15 + ((n) * 2))
+
 static inline void sysctl_soft_reset(void __iomem *base)
 {
 	/* switch to slow mode */

drivers/clk/Kconfig

@@ -42,10 +42,12 @@ config COMMON_CLK_WM831X
 
 config COMMON_CLK_VERSATILE
 	bool "Clock driver for ARM Reference designs"
-	depends on ARCH_INTEGRATOR || ARCH_REALVIEW
+	depends on ARCH_INTEGRATOR || ARCH_REALVIEW || ARCH_VEXPRESS
 	---help---
-          Supports clocking on ARM Reference designs Integrator/AP,
-	  Integrator/CP, RealView PB1176, EB, PB11MP and PBX.
+          Supports clocking on ARM Reference designs:
+	  - Integrator/AP and Integrator/CP
+	  - RealView PB1176, EB, PB11MP and PBX
+	  - Versatile Express
 
 config COMMON_CLK_MAX77686
 	tristate "Clock driver for Maxim 77686 MFD"

drivers/clk/versatile/Makefile

@@ -2,4 +2,5 @@
 obj-$(CONFIG_ICST)		+= clk-icst.o
 obj-$(CONFIG_ARCH_INTEGRATOR)	+= clk-integrator.o
 obj-$(CONFIG_ARCH_REALVIEW)	+= clk-realview.o
+obj-$(CONFIG_ARCH_VEXPRESS)	+= clk-vexpress.o
 obj-$(CONFIG_VEXPRESS_CONFIG)	+= clk-vexpress-osc.o

drivers/clk/versatile/clk-vexpress.c

@@ -0,0 +1,142 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/vexpress.h>
+
+#include <asm/hardware/sp810.h>
+
+static struct clk *vexpress_sp810_timerclken[4];
+static DEFINE_SPINLOCK(vexpress_sp810_lock);
+
+static void __init vexpress_sp810_init(void __iomem *base)
+{
+	int i;
+
+	if (WARN_ON(!base))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++) {
+		char name[12];
+		const char *parents[] = {
+			"v2m:refclk32khz", /* REFCLK */
+			"v2m:refclk1mhz" /* TIMCLK */
+		};
+
+		snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
+
+		vexpress_sp810_timerclken[i] = clk_register_mux(NULL, name,
+				parents, 2, 0, base + SCCTRL,
+				SCCTRL_TIMERENnSEL_SHIFT(i), 1,
+				0, &vexpress_sp810_lock);
+
+		if (WARN_ON(IS_ERR(vexpress_sp810_timerclken[i])))
+			break;
+	}
+}
+
+
+static const char * const vexpress_clk_24mhz_periphs[] __initconst = {
+	"mb:uart0", "mb:uart1", "mb:uart2", "mb:uart3",
+	"mb:mmci", "mb:kmi0", "mb:kmi1"
+};
+
+void __init vexpress_clk_init(void __iomem *sp810_base)
+{
+	struct clk *clk;
+	int i;
+
+	clk = clk_register_fixed_rate(NULL, "dummy_apb_pclk", NULL,
+			CLK_IS_ROOT, 0);
+	WARN_ON(clk_register_clkdev(clk, "apb_pclk", NULL));
+
+	clk = clk_register_fixed_rate(NULL, "v2m:clk_24mhz", NULL,
+			CLK_IS_ROOT, 24000000);
+	for (i = 0; i < ARRAY_SIZE(vexpress_clk_24mhz_periphs); i++)
+		WARN_ON(clk_register_clkdev(clk, NULL,
+				vexpress_clk_24mhz_periphs[i]));
+
+	clk = clk_register_fixed_rate(NULL, "v2m:refclk32khz", NULL,
+			CLK_IS_ROOT, 32768);
+	WARN_ON(clk_register_clkdev(clk, NULL, "v2m:wdt"));
+
+	clk = clk_register_fixed_rate(NULL, "v2m:refclk1mhz", NULL,
+			CLK_IS_ROOT, 1000000);
+
+	vexpress_sp810_init(sp810_base);
+
+	for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
+		WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i], clk));
+
+	WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
+				"v2m-timer0", "sp804"));
+	WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
+				"v2m-timer1", "sp804"));
+}
+
+#if defined(CONFIG_OF)
+
+struct clk *vexpress_sp810_of_get(struct of_phandle_args *clkspec, void *data)
+{
+	if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
+			ARRAY_SIZE(vexpress_sp810_timerclken)))
+		return NULL;
+
+	return vexpress_sp810_timerclken[clkspec->args[0]];
+}
+
+static const __initconst struct of_device_id vexpress_fixed_clk_match[] = {
+	{ .compatible = "fixed-clock", .data = of_fixed_clk_setup, },
+	{ .compatible = "arm,vexpress-osc", .data = vexpress_osc_of_setup, },
+	{}
+};
+
+void __init vexpress_clk_of_init(void)
+{
+	struct device_node *node;
+	struct clk *clk;
+	struct clk *refclk, *timclk;
+
+	of_clk_init(vexpress_fixed_clk_match);
+
+	node = of_find_compatible_node(NULL, NULL, "arm,sp810");
+	vexpress_sp810_init(of_iomap(node, 0));
+	of_clk_add_provider(node, vexpress_sp810_of_get, NULL);
+
+	/* Select "better" (faster) parent for SP804 timers */
+	refclk = of_clk_get_by_name(node, "refclk");
+	timclk = of_clk_get_by_name(node, "timclk");
+	if (!WARN_ON(IS_ERR(refclk) || IS_ERR(timclk))) {
+		int i = 0;
+
+		if (clk_get_rate(refclk) > clk_get_rate(timclk))
+			clk = refclk;
+		else
+			clk = timclk;
+
+		for (i = 0; i < ARRAY_SIZE(vexpress_sp810_timerclken); i++)
+			WARN_ON(clk_set_parent(vexpress_sp810_timerclken[i],
+					clk));
+	}
+
+	WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[0],
+				"v2m-timer0", "sp804"));
+	WARN_ON(clk_register_clkdev(vexpress_sp810_timerclken[1],
+				"v2m-timer1", "sp804"));
+}
+
+#endif