diff options
Diffstat (limited to 'drivers/clocksource/i8253.c')
| -rw-r--r-- | drivers/clocksource/i8253.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c index 33735ebd2dc..e594f52eb88 100644 --- a/drivers/clocksource/i8253.c +++ b/drivers/clocksource/i8253.c @@ -6,10 +6,20 @@ #include <linux/io.h> #include <linux/spinlock.h> #include <linux/timex.h> - +#include <linux/module.h> #include <linux/i8253.h> /* + * Protects access to I/O ports + * + * 0040-0043 : timer0, i8253 / i8254 + * 0061-0061 : NMI Control Register which contains two speaker control bits. + */ +DEFINE_RAW_SPINLOCK(i8253_lock); +EXPORT_SYMBOL(i8253_lock); + +#ifdef CONFIG_CLKSRC_I8253 +/* * Since the PIT overflows every tick, its not very useful * to just read by itself. So use jiffies to emulate a free * running counter: @@ -86,3 +96,4 @@ int __init clocksource_i8253_init(void) { return clocksource_register_hz(&i8253_cs, PIT_TICK_RATE); } +#endif |