ARM: AT91: Add DT support to AT91RM9200 System Timer

Based on AT91 PIT DT patch from Jean-Christophe PLAGNIOL-VILLARD.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

1 files changed, 61 insertions, 2 deletions

diff --git a/arch/arm/mach-at91/at91rm9200_time.c b/arch/arm/mach-at91/at91rm9200_time.c
index aaa443b48c91..cafe98836c8a 100644
--- a/arch/arm/mach-at91/at91rm9200_time.c
+++ b/arch/arm/mach-at91/at91rm9200_time.c
@@ -24,6 +24,9 @@
 #include <linux/irq.h>
 #include <linux/clockchips.h>
 #include <linux/export.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
 
 #include <asm/mach/time.h>
 
@@ -91,7 +94,8 @@ static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
 static struct irqaction at91rm9200_timer_irq = {
         .name           = "at91_tick",
         .flags          = IRQF_SHARED | IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
-        .handler        = at91rm9200_timer_interrupt
+        .handler        = at91rm9200_timer_interrupt,
+        .irq            = NR_IRQS_LEGACY + AT91_ID_SYS,
 };
 
 static cycle_t read_clk32k(struct clocksource *cs)
@@ -179,8 +183,60 @@ static struct clock_event_device clkevt = {
 void __iomem *at91_st_base;
 EXPORT_SYMBOL_GPL(at91_st_base);
 
+#ifdef CONFIG_OF
+static struct of_device_id at91rm9200_st_timer_ids[] = {
+        { .compatible = "atmel,at91rm9200-st" },
+        { /* sentinel */ }
+};
+
+static int __init of_at91rm9200_st_init(void)
+{
+        struct device_node *np;
+        int ret;
+
+        np = of_find_matching_node(NULL, at91rm9200_st_timer_ids);
+        if (!np)
+                goto err;
+
+        at91_st_base = of_iomap(np, 0);
+        if (!at91_st_base)
+                goto node_err;
+
+        /* Get the interrupts property */
+        ret = irq_of_parse_and_map(np, 0);
+        if (!ret)
+                goto ioremap_err;
+        at91rm9200_timer_irq.irq = ret;
+
+        of_node_put(np);
+
+        return 0;
+
+ioremap_err:
+        iounmap(at91_st_base);
+node_err:
+        of_node_put(np);
+err:
+        return -EINVAL;
+}
+#else
+static int __init of_at91rm9200_st_init(void)
+{
+        return -EINVAL;
+}
+#endif
+
 void __init at91rm9200_ioremap_st(u32 addr)
 {
+#ifdef CONFIG_OF
+        struct device_node *np;
+
+        np = of_find_matching_node(NULL, at91rm9200_st_timer_ids);
+        if (np) {
+                of_node_put(np);
+                return;
+        }
+#endif
         at91_st_base = ioremap(addr, 256);
         if (!at91_st_base)
                 panic("Impossible to ioremap ST\n");
@@ -191,13 +247,16 @@ void __init at91rm9200_ioremap_st(u32 addr)
  */
 void __init at91rm9200_timer_init(void)
 {
+        /* For device tree enabled device: initialize here */
+        of_at91rm9200_st_init();
+
         /* Disable all timer interrupts, and clear any pending ones */
         at91_st_write(AT91_ST_IDR,
                 AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS);
         at91_st_read(AT91_ST_SR);
 
         /* Make IRQs happen for the system timer */
-        setup_irq(NR_IRQS_LEGACY + AT91_ID_SYS, &at91rm9200_timer_irq);
+        setup_irq(at91rm9200_timer_irq.irq, &at91rm9200_timer_irq);
 
         /* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used
          * directly for the clocksource and all clockevents, after adjusting