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Subject[RFC v2 6/9] arm/dt: add devicetree support to sp804 timer support
Date
This patch adds support to the sp804 code for retrieving timer
configuration from the device tree. sp804 channels can be used as
a clock event device or a clock source.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Russell King <linux@arm.linux.org.uk>
---
arch/arm/common/timer-sp.c | 72 ++++++++++++++++++++++++++---
arch/arm/include/asm/hardware/timer-sp.h | 2 +
2 files changed, 66 insertions(+), 8 deletions(-)
diff --git a/arch/arm/common/timer-sp.c b/arch/arm/common/timer-sp.c
index 2393b5b..93aed48 100644
--- a/arch/arm/common/timer-sp.c
+++ b/arch/arm/common/timer-sp.c
@@ -25,16 +25,18 @@
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_clk.h>
+#include <linux/of_irq.h>

#include <asm/hardware/arm_timer.h>

-static long __init sp804_get_clock_rate(const char *name)
+static long __init sp804_get_clock_rate(struct clk *clk, const char *name)
{
- struct clk *clk;
long rate;
int err;

- clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: %s clock not found: %d\n", name,
(int)PTR_ERR(clk));
@@ -67,9 +69,10 @@ static long __init sp804_get_clock_rate(const char *name)
return rate;
}

-void __init sp804_clocksource_init(void __iomem *base, const char *name)
+static void __init __sp804_clocksource_init(void __iomem *base,
+ const char *name, struct clk *clk)
{
- long rate = sp804_get_clock_rate(name);
+ long rate = sp804_get_clock_rate(clk, name);

if (rate < 0)
return;
@@ -85,6 +88,10 @@ void __init sp804_clocksource_init(void __iomem *base, const char *name)
rate, 200, 32, clocksource_mmio_readl_down);
}

+void __init sp804_clocksource_init(void __iomem *base, const char *name)
+{
+ __sp804_clocksource_init(base, name, clk_get_sys("sp804", name));
+}

static void __iomem *clkevt_base;
static unsigned long clkevt_reload;
@@ -158,11 +165,11 @@ static struct irqaction sp804_timer_irq = {
.dev_id = &sp804_clockevent,
};

-void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
- const char *name)
+static void __init __sp804_clockevents_init(void __iomem *base,
+ unsigned int irq, const char *name, struct clk *clk)
{
struct clock_event_device *evt = &sp804_clockevent;
- long rate = sp804_get_clock_rate(name);
+ long rate = sp804_get_clock_rate(clk, name);

if (rate < 0)
return;
@@ -179,3 +186,52 @@ void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
setup_irq(irq, &sp804_timer_irq);
clockevents_register_device(evt);
}
+
+void __init sp804_clockevents_init(void __iomem *base, unsigned int irq,
+ const char *name)
+{
+ __sp804_clockevents_init(base, irq, name, clk_get_sys("sp804", name));
+}
+
+#ifdef CONFIG_OF
+void __init sp804_dt_setup(struct device_node *node)
+{
+ struct clk *clk;
+ unsigned int irq;
+ __iomem void * base;
+
+ pr_debug("%s(): Setting up sp804 clock %s\n", __func__, node->name);
+
+ /* Find the base address of the clock */
+ base = of_iomap(node, 0);
+ if (!base) {
+ pr_err("ERROR: Cannot get base address of sp804 %s\n",
+ node->full_name);
+ return;
+ }
+
+ writel(0, base + TIMER_CTRL); /* Disable the clock */
+
+ clk = of_clk_get(node, 0);
+ if (!clk) {
+ pr_err("ERROR: Cannot get clock for sp804 %s\n", node->name);
+ return;
+ }
+
+ /*
+ * Figure out how to use this clock
+ *
+ * Note: This is kind of ugly since it requires linux-specific
+ * properties in the device tree so that Linux knows which sp804
+ * channels can be used as the clock source and the clock events
+ * trigger. Something OS agnostic would be nicer, but it isn't
+ * obvious what that should look like.
+ */
+ if (of_get_property(node, "linux,clock-source", NULL)) {
+ __sp804_clocksource_init(base, node->full_name, clk);
+ } else if (of_get_property(node, "linux,clockevents-device", NULL)) {
+ irq = irq_of_parse_and_map(node, 0);
+ __sp804_clockevents_init(base, irq, node->full_name, clk);
+ };
+}
+#endif /* CONFIG_OF */
diff --git a/arch/arm/include/asm/hardware/timer-sp.h b/arch/arm/include/asm/hardware/timer-sp.h
index 4384d81..edd0ec3 100644
--- a/arch/arm/include/asm/hardware/timer-sp.h
+++ b/arch/arm/include/asm/hardware/timer-sp.h
@@ -1,2 +1,4 @@
+struct device_node;
void sp804_clocksource_init(void __iomem *, const char *);
void sp804_clockevents_init(void __iomem *, unsigned int, const char *);
+void sp804_dt_setup(struct device_node *node);
--
1.7.5.4


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