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clocksource: kona: Add basic use of external clock

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When an clock is specified in the device tree, enable it and use it to
determine the external clock frequency.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Christian Daudt <bcm@fixthebug.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Christian Daudt <bcm@fixthebug.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Tim Kryger
2013-12-05 11:20:43 -08:00
committed by Olof Johansson
parent 7c762036e2
commit 50ac206102
1 changed files with 11 additions and 3 deletions
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14
drivers/clocksource/bcm_kona_timer.c
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@@ -17,6 +17,7 @@
#include <linux/jiffies.h> #include <linux/jiffies.h>
#include <linux/clockchips.h> #include <linux/clockchips.h>
#include <linux/types.h> #include <linux/types.h>
#include <linux/clk.h>
#include <linux/io.h> #include <linux/io.h>
#include <asm/mach/time.h> #include <asm/mach/time.h>
@@ -101,11 +102,18 @@ kona_timer_get_counter(void *timer_base, uint32_t *msw, uint32_t *lsw)
static void __init kona_timers_init(struct device_node *node) static void __init kona_timers_init(struct device_node *node)
{ {
u32 freq; u32 freq;
struct clk *external_clk;
if (!of_property_read_u32(node, "clock-frequency", &freq)) external_clk = of_clk_get_by_name(node, NULL);
if (!IS_ERR(external_clk)) {
arch_timer_rate = clk_get_rate(external_clk);
clk_prepare_enable(external_clk);
} else if (!of_property_read_u32(node, "clock-frequency", &freq)) {
arch_timer_rate = freq; arch_timer_rate = freq;
else } else {
panic("clock-frequency not set in the .dts file"); panic("unable to determine clock-frequency");
}
/* Setup IRQ numbers */ /* Setup IRQ numbers */
timers.tmr_irq = irq_of_parse_and_map(node, 0); timers.tmr_irq = irq_of_parse_and_map(node, 0);