1 files changed, 63 insertions, 32 deletions

diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index ab09ed3742ee..cef554432a33 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -20,6 +20,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/clk.h>
 
 #include <asm/mach/time.h>
 #include <asm/sched_clock.h>
@@ -27,14 +28,37 @@
 static void timer_get_base_and_rate(struct device_node *np,
 				    void __iomem **base, u32 *rate)
 {
+	struct clk *timer_clk;
+	struct clk *pclk;
+
 	*base = of_iomap(np, 0);
 
 	if (!*base)
 		panic("Unable to map regs for %s", np->name);
 
+	/*
+	 * Not all implementations use a periphal clock, so don't panic
+	 * if it's not present
+	 */
+	pclk = of_clk_get_by_name(np, "pclk");
+	if (!IS_ERR(pclk))
+		if (clk_prepare_enable(pclk))
+			pr_warn("pclk for %s is present, but could not be activated\n",
+				np->name);
+
+	timer_clk = of_clk_get_by_name(np, "timer");
+	if (IS_ERR(timer_clk))
+		goto try_clock_freq;
+
+	if (!clk_prepare_enable(timer_clk)) {
+		*rate = clk_get_rate(timer_clk);
+		return;
+	}
+
+try_clock_freq:
 	if (of_property_read_u32(np, "clock-freq", rate) &&
 		of_property_read_u32(np, "clock-frequency", rate))
-		panic("No clock-frequency property for %s", np->name);
+		panic("No clock nor clock-frequency property for %s", np->name);
 }
 
 static void add_clockevent(struct device_node *event_timer)
@@ -57,6 +81,9 @@ static void add_clockevent(struct device_node *event_timer)
 	dw_apb_clockevent_register(ced);
 }
 
+static void __iomem *sched_io_base;
+static u32 sched_rate;
+
 static void add_clocksource(struct device_node *source_timer)
 {
 	void __iomem *iobase;
@@ -71,9 +98,15 @@ static void add_clocksource(struct device_node *source_timer)
 
 	dw_apb_clocksource_start(cs);
 	dw_apb_clocksource_register(cs);
-}
 
-static void __iomem *sched_io_base;
+	/*
+	 * Fallback to use the clocksource as sched_clock if no separate
+	 * timer is found. sched_io_base then points to the current_value
+	 * register of the clocksource timer.
+	 */
+	sched_io_base = iobase + 0x04;
+	sched_rate = rate;
+}
 
 static u32 read_sched_clock(void)
 {
@@ -89,39 +122,37 @@ static const struct of_device_id sptimer_ids[] __initconst = {
 static void init_sched_clock(void)
 {
 	struct device_node *sched_timer;
-	u32 rate;
 
 	sched_timer = of_find_matching_node(NULL, sptimer_ids);
-	if (!sched_timer)
-		panic("No RTC for sched clock to use");
+	if (sched_timer) {
+		timer_get_base_and_rate(sched_timer, &sched_io_base,
+					&sched_rate);
+		of_node_put(sched_timer);
+	}
 
-	timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
-	of_node_put(sched_timer);
-
-	setup_sched_clock(read_sched_clock, 32, rate);
+	setup_sched_clock(read_sched_clock, 32, sched_rate);
 }
 
-static const struct of_device_id osctimer_ids[] __initconst = {
-	{ .compatible = "picochip,pc3x2-timer" },
-	{ .compatible = "snps,dw-apb-timer-osc" },
-	{},
-};
-
-void __init dw_apb_timer_init(void)
+static int num_called;
+static void __init dw_apb_timer_init(struct device_node *timer)
 {
-	struct device_node *event_timer, *source_timer;
-
-	event_timer = of_find_matching_node(NULL, osctimer_ids);
-	if (!event_timer)
-		panic("No timer for clockevent");
-	add_clockevent(event_timer);
-
-	source_timer = of_find_matching_node(event_timer, osctimer_ids);
-	if (!source_timer)
-		panic("No timer for clocksource");
-	add_clocksource(source_timer);
-
-	of_node_put(source_timer);
-
-	init_sched_clock();
+	switch (num_called) {
+	case 0:
+		pr_debug("%s: found clockevent timer\n", __func__);
+		add_clockevent(timer);
+		of_node_put(timer);
+		break;
+	case 1:
+		pr_debug("%s: found clocksource timer\n", __func__);
+		add_clocksource(timer);
+		of_node_put(timer);
+		init_sched_clock();
+		break;
+	default:
+		break;
+	}
+
+	num_called++;
 }
+CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer-osc", dw_apb_timer_init);