From 50ac206102660fe29e75d8a685178db95c530f4f Mon Sep 17 00:00:00 2001
From: Tim Kryger <tim.kryger@linaro.org>
Date: Thu, 5 Dec 2013 11:20:43 -0800
Subject: [PATCH] clocksource: kona: Add basic use of external clock
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>
---
drivers/clocksource/bcm_kona_timer.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/clocksource/bcm_kona_timer.c b/drivers/clocksource/bcm_kona_timer.c
index 5176e761166b..974b2db2fe10 100644
--- a/drivers/clocksource/bcm_kona_timer.c
+++ b/drivers/clocksource/bcm_kona_timer.c
@@ -17,6 +17,7 @@
#include <linux/jiffies.h>
#include <linux/clockchips.h>
#include <linux/types.h>
+#include <linux/clk.h>
#include <linux/io.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)
{
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;
- else
- panic("clock-frequency not set in the .dts file");
+ } else {
+ panic("unable to determine clock-frequency");
+ }
/* Setup IRQ numbers */
timers.tmr_irq = irq_of_parse_and_map(node, 0);