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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-05-12 08:31:48 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-05-23 13:04:53 -0400
commit7ff550de99141cbd3be0129d563cc4554fdde9f6 (patch)
tree21381e1dcdbd69b461cefc696a1a1fd80f38ce8e /arch/arm/common
parentfb593cf38fc426331275d761fefe13096070f56a (diff)
clocksource: ARM sp804: obtain sp804 timer rate via clks
This allows platforms to specify the rate of the SP804 clocksource via the clk subsystem. While ARM boards clock these at 1MHz, BCMRing also has SP804 timers but are clocked at different rates. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/common')
-rw-r--r--arch/arm/common/timer-sp.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/arch/arm/common/timer-sp.c b/arch/arm/common/timer-sp.c
index f6b9011744aa..166f892a24d5 100644
--- a/arch/arm/common/timer-sp.c
+++ b/arch/arm/common/timer-sp.c
@@ -18,8 +18,10 @@
18 * along with this program; if not, write to the Free Software 18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */ 20 */
21#include <linux/clk.h>
21#include <linux/clocksource.h> 22#include <linux/clocksource.h>
22#include <linux/clockchips.h> 23#include <linux/clockchips.h>
24#include <linux/err.h>
23#include <linux/interrupt.h> 25#include <linux/interrupt.h>
24#include <linux/irq.h> 26#include <linux/irq.h>
25#include <linux/io.h> 27#include <linux/io.h>
@@ -32,8 +34,43 @@
32#define TIMER_FREQ_KHZ (1000) 34#define TIMER_FREQ_KHZ (1000)
33#define TIMER_RELOAD (TIMER_FREQ_KHZ * 1000 / HZ) 35#define TIMER_RELOAD (TIMER_FREQ_KHZ * 1000 / HZ)
34 36
37static long __init sp804_get_clock_rate(const char *name)
38{
39 struct clk *clk;
40 long rate;
41 int err;
42
43 clk = clk_get_sys("sp804", name);
44 if (IS_ERR(clk)) {
45 pr_err("sp804: %s clock not found: %d\n", name,
46 (int)PTR_ERR(clk));
47 return PTR_ERR(clk);
48 }
49
50 err = clk_enable(clk);
51 if (err) {
52 pr_err("sp804: %s clock failed to enable: %d\n", name, err);
53 clk_put(clk);
54 return err;
55 }
56
57 rate = clk_get_rate(clk);
58 if (rate < 0) {
59 pr_err("sp804: %s clock failed to get rate: %ld\n", name, rate);
60 clk_disable(clk);
61 clk_put(clk);
62 }
63
64 return rate;
65}
66
35void __init sp804_clocksource_init(void __iomem *base, const char *name) 67void __init sp804_clocksource_init(void __iomem *base, const char *name)
36{ 68{
69 long rate = sp804_get_clock_rate(name);
70
71 if (rate < 0)
72 return;
73
37 /* setup timer 0 as free-running clocksource */ 74 /* setup timer 0 as free-running clocksource */
38 writel(0, base + TIMER_CTRL); 75 writel(0, base + TIMER_CTRL);
39 writel(0xffffffff, base + TIMER_LOAD); 76 writel(0xffffffff, base + TIMER_LOAD);
@@ -42,7 +79,7 @@ void __init sp804_clocksource_init(void __iomem *base, const char *name)
42 base + TIMER_CTRL); 79 base + TIMER_CTRL);
43 80
44 clocksource_mmio_init(base + TIMER_VALUE, name, 81 clocksource_mmio_init(base + TIMER_VALUE, name,
45 TIMER_FREQ_KHZ * 1000, 200, 32, clocksource_mmio_readl_down); 82 rate, 200, 32, clocksource_mmio_readl_down);
46} 83}
47 84
48 85