clocksource: mips-gic: Add device-tree support

Parse the GIC timer frequency and interrupt from the device-tree.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8421/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 35 insertions, 7 deletions

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index cb7e7f417a60..89836dc7cf66 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -226,5 +226,6 @@ config CLKSRC_VERSATILE
 config CLKSRC_MIPS_GIC
         bool
         depends on MIPS_GIC
+        select CLKSRC_OF
 
 endmenu
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index a749c812e255..3bd31b1321f6 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -11,6 +11,7 @@
 #include <linux/interrupt.h>
 #include <linux/irqchip/mips-gic.h>
 #include <linux/notifier.h>
+#include <linux/of_irq.h>
 #include <linux/percpu.h>
 #include <linux/smp.h>
 #include <linux/time.h>
@@ -101,8 +102,6 @@ static int gic_clockevent_init(void)
         if (!cpu_has_counter || !gic_frequency)
                 return -ENXIO;
 
-        gic_timer_irq = MIPS_GIC_IRQ_BASE +
-                GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
         setup_percpu_irq(gic_timer_irq, &gic_compare_irqaction);
 
         register_cpu_notifier(&gic_cpu_nb);
@@ -123,17 +122,45 @@ static struct clocksource gic_clocksource = {
         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-void __init gic_clocksource_init(unsigned int frequency)
+static void __init __gic_clocksource_init(void)
 {
-        gic_frequency = frequency;
-
         /* Set clocksource mask. */
         gic_clocksource.mask = CLOCKSOURCE_MASK(gic_get_count_width());
 
         /* Calculate a somewhat reasonable rating value. */
-        gic_clocksource.rating = 200 + frequency / 10000000;
+        gic_clocksource.rating = 200 + gic_frequency / 10000000;
 
-        clocksource_register_hz(&gic_clocksource, frequency);
+        clocksource_register_hz(&gic_clocksource, gic_frequency);
 
         gic_clockevent_init();
 }
+
+void __init gic_clocksource_init(unsigned int frequency)
+{
+        gic_frequency = frequency;
+        gic_timer_irq = MIPS_GIC_IRQ_BASE +
+                GIC_LOCAL_TO_HWIRQ(GIC_LOCAL_INT_COMPARE);
+
+        __gic_clocksource_init();
+}
+
+static void __init gic_clocksource_of_init(struct device_node *node)
+{
+        if (WARN_ON(!gic_present || !node->parent ||
+                    !of_device_is_compatible(node->parent, "mti,gic")))
+                return;
+
+        if (of_property_read_u32(node, "clock-frequency", &gic_frequency)) {
+                pr_err("GIC frequency not specified.\n");
+                return;
+        }
+        gic_timer_irq = irq_of_parse_and_map(node, 0);
+        if (!gic_timer_irq) {
+                pr_err("GIC timer IRQ not specified.\n");
+                return;
+        }
+
+        __gic_clocksource_init();
+}
+CLOCKSOURCE_OF_DECLARE(mips_gic_timer, "mti,gic-timer",
+                       gic_clocksource_of_init);