[PATCH] clk: vexpress: Add separate SP810 driver

Pawel Moll pawel.moll at arm.com
Fri Mar 15 10:40:09 EDT 2013


Factor out the SP810 clocking code into a separate driver,
selecting better (faster) parent at clk_prepare() time.
This is to avoid problems with clocking infrastructure
initialisation order, in particular to avoid dependency
of fixed clock being initialized before SP810. It also
makes vexpress platform OF-based clock initialisation code
unnecessary.

Signed-off-by: Pawel Moll <pawel.moll at arm.com>
---
 arch/arm/mach-vexpress/v2m.c         |    8 +-
 drivers/clk/versatile/Makefile       |    2 +-
 drivers/clk/versatile/clk-sp810.c    |  172 ++++++++++++++++++++++++++++++++++
 drivers/clk/versatile/clk-vexpress.c |   49 ----------
 4 files changed, 180 insertions(+), 51 deletions(-)
 create mode 100644 drivers/clk/versatile/clk-sp810.c

Hi Mike,

I'd like to get this merged in 3.10. After this arm64
will be able to avoid any platform clocking code. And
in case of v7 this will happen once Rob's SP804 work
is done.

Thanks!

Pawel

diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
index 915683c..c5e20b5 100644
--- a/arch/arm/mach-vexpress/v2m.c
+++ b/arch/arm/mach-vexpress/v2m.c
@@ -21,6 +21,8 @@
 #include <linux/regulator/fixed.h>
 #include <linux/regulator/machine.h>
 #include <linux/vexpress.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
 
 #include <asm/arch_timer.h>
 #include <asm/mach-types.h>
@@ -433,7 +435,7 @@ static void __init v2m_dt_timer_init(void)
 {
 	struct device_node *node = NULL;
 
-	vexpress_clk_of_init();
+	of_clk_init(NULL);
 
 	do {
 		node = of_find_compatible_node(node, NULL, "arm,sp804");
@@ -441,6 +443,10 @@ static void __init v2m_dt_timer_init(void)
 	if (node) {
 		pr_info("Using SP804 '%s' as a clock & events source\n",
 				node->full_name);
+		WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
+				"timclken1"), "v2m-timer0", "sp804"));
+		WARN_ON(clk_register_clkdev(of_clk_get_by_name(node,
+				"timclken2"), "v2m-timer1", "sp804"));
 		v2m_sp804_init(of_iomap(node, 0),
 				irq_of_parse_and_map(node, 0));
 	}
diff --git a/drivers/clk/versatile/Makefile b/drivers/clk/versatile/Makefile
index ec3b88f..c16ca78 100644
--- a/drivers/clk/versatile/Makefile
+++ b/drivers/clk/versatile/Makefile
@@ -3,5 +3,5 @@ obj-$(CONFIG_ICST)		+= clk-icst.o
 obj-$(CONFIG_ARCH_INTEGRATOR)	+= clk-integrator.o
 obj-$(CONFIG_INTEGRATOR_IMPD1)	+= clk-impd1.o
 obj-$(CONFIG_ARCH_REALVIEW)	+= clk-realview.o
-obj-$(CONFIG_ARCH_VEXPRESS)	+= clk-vexpress.o
+obj-$(CONFIG_ARCH_VEXPRESS)	+= clk-vexpress.o clk-sp810.o
 obj-$(CONFIG_VEXPRESS_CONFIG)	+= clk-vexpress-osc.o
diff --git a/drivers/clk/versatile/clk-sp810.c b/drivers/clk/versatile/clk-sp810.c
new file mode 100644
index 0000000..1c2a7f4
--- /dev/null
+++ b/drivers/clk/versatile/clk-sp810.c
@@ -0,0 +1,172 @@
+/*
+ * 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) 2013 ARM Limited
+ */
+
+#include <linux/amba/sp810.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define to_clk_sp810_timerclken(_hw) \
+		container_of(_hw, struct clk_sp810_timerclken, hw)
+
+struct clk_sp810;
+
+struct clk_sp810_timerclken {
+	struct clk_hw hw;
+	struct clk *clk;
+	struct clk_sp810 *sp810;
+	int channel;
+};
+
+struct clk_sp810 {
+	struct device_node *node;
+	int refclk_index, timclk_index;
+	void __iomem *base;
+	spinlock_t lock;
+	struct clk_sp810_timerclken timerclken[4];
+};
+
+static u8 clk_sp810_timerclken_get_parent(struct clk_hw *hw)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	u32 val = readl(timerclken->sp810->base + SCCTRL);
+
+	return !!(val & (1 << SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel)));
+}
+
+static int clk_sp810_timerclken_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	struct clk_sp810 *sp810 = timerclken->sp810;
+	u32 val, shift = SCCTRL_TIMERENnSEL_SHIFT(timerclken->channel);
+	unsigned long flags = 0;
+
+	if (WARN_ON(index > 1))
+		return -EINVAL;
+
+	spin_lock_irqsave(&sp810->lock, flags);
+
+	val = readl(sp810->base + SCCTRL);
+	val &= ~(1 << shift);
+	val |= index << shift;
+	writel(val, sp810->base + SCCTRL);
+
+	spin_unlock_irqrestore(&sp810->lock, flags);
+
+	return 0;
+}
+
+static int clk_sp810_timerclken_prepare(struct clk_hw *hw)
+{
+	struct clk_sp810_timerclken *timerclken = to_clk_sp810_timerclken(hw);
+	struct clk_sp810 *sp810 = timerclken->sp810;
+	struct clk *refclk = of_clk_get(sp810->node, sp810->refclk_index);
+	struct clk *timclk = of_clk_get(sp810->node, sp810->timclk_index);
+	struct clk *old_parent = __clk_get_parent(hw->clk);
+	struct clk *new_parent = old_parent;
+	int new_parent_index;
+
+	if (WARN_ON(IS_ERR(refclk) || IS_ERR(timclk)))
+		return -ENOENT;
+
+	/* Select "better" (faster) parent */
+	if (__clk_get_rate(refclk) > __clk_get_rate(timclk)) {
+		new_parent = refclk;
+		new_parent_index = 0;
+	} else {
+		new_parent = timclk;
+		new_parent_index = 1;
+	}
+
+	/* Switch the parent if necessary */
+	if (old_parent != new_parent) {
+		__clk_prepare(new_parent);
+		clk_sp810_timerclken_set_parent(hw, new_parent_index);
+		__clk_reparent(hw->clk, new_parent);
+		__clk_unprepare(old_parent);
+	}
+
+	return 0;
+}
+
+static const struct clk_ops clk_sp810_timerclken_ops = {
+	.prepare = clk_sp810_timerclken_prepare,
+	.get_parent = clk_sp810_timerclken_get_parent,
+	.set_parent = clk_sp810_timerclken_set_parent,
+};
+
+struct clk *clk_sp810_timerclken_of_get(struct of_phandle_args *clkspec,
+		void *data)
+{
+	struct clk_sp810 *sp810 = data;
+
+	if (WARN_ON(clkspec->args_count != 1 || clkspec->args[0] >
+			ARRAY_SIZE(sp810->timerclken)))
+		return NULL;
+
+	return sp810->timerclken[clkspec->args[0]].clk;
+}
+
+void __init clk_sp810_of_setup(struct device_node *node)
+{
+	struct clk_sp810 *sp810 = kzalloc(sizeof(*sp810), GFP_KERNEL);
+	const char *parent_names[2];
+	char name[12];
+	struct clk_init_data init;
+	int i;
+
+	if (!sp810) {
+		pr_err("Failed to allocate memory for SP810!\n");
+		return;
+	}
+
+	sp810->refclk_index = of_property_match_string(node, "clock-names",
+			"refclk");
+	parent_names[0] = of_clk_get_parent_name(node, sp810->refclk_index);
+
+	sp810->timclk_index = of_property_match_string(node, "clock-names",
+			"timclk");
+	parent_names[1] = of_clk_get_parent_name(node, sp810->timclk_index);
+
+	if (parent_names[0] <= 0 || parent_names[1] <= 0) {
+		pr_warn("Failed to obtain parent clocks for SP810!\n");
+		return;
+	}
+
+	sp810->node = node;
+	sp810->base = of_iomap(node, 0);
+	spin_lock_init(&sp810->lock);
+
+	init.name = name;
+	init.ops = &clk_sp810_timerclken_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = ARRAY_SIZE(parent_names);
+
+	for (i = 0; i < ARRAY_SIZE(sp810->timerclken); i++) {
+		snprintf(name, ARRAY_SIZE(name), "timerclken%d", i);
+
+		sp810->timerclken[i].sp810 = sp810;
+		sp810->timerclken[i].channel = i;
+		sp810->timerclken[i].hw.init = &init;
+
+		sp810->timerclken[i].clk = clk_register(NULL,
+				&sp810->timerclken[i].hw);
+		WARN_ON(IS_ERR(sp810->timerclken[i].clk));
+	}
+
+	of_clk_add_provider(node, clk_sp810_timerclken_of_get, sp810);
+}
+CLK_OF_DECLARE(sp810, "arm,sp810", clk_sp810_of_setup);
diff --git a/drivers/clk/versatile/clk-vexpress.c b/drivers/clk/versatile/clk-vexpress.c
index 82b45aa..a4a728d 100644
--- a/drivers/clk/versatile/clk-vexpress.c
+++ b/drivers/clk/versatile/clk-vexpress.c
@@ -15,8 +15,6 @@
 #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>
 
 static struct clk *vexpress_sp810_timerclken[4];
@@ -86,50 +84,3 @@ void __init vexpress_clk_init(void __iomem *sp810_base)
 	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]];
-}
-
-void __init vexpress_clk_of_init(void)
-{
-	struct device_node *node;
-	struct clk *clk;
-	struct clk *refclk, *timclk;
-
-	of_clk_init(NULL);
-
-	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
-- 
1.7.10.4





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