clocksource: dw_apb_timer_of: add clock-handling
Add the possibility to get the clock-frequency from a timer clock instead
of specifying it as dt property. Additionally also add the possibility
to also define a controlling periphal clock for the timer block.
The clock-frequency property is kept to act as fallback if no clocks
are specified.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Jamie Iles <jamie@jamieiles.com>
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index d6c0fda..1964f87 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)