rtc: use the IRQ callback interface in (old) RTC driver

the previous patch in the old RTC driver.  It also removes the direct
rtc_interrupt() call from arch/x86/kernel/hpetc.c so that there's finally no
(code) dependency to CONFIG_RTC in arch/x86/kernel/hpet.c.

Because of this, it's possible to compile the drivers/char/rtc.ko driver as
module and still use the HPET emulation functionality.  This is also expressed
in Kconfig.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Robert Picco <Robert.Picco@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 1 insertions, 3 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 81af31e5a9f1..4e911d0a4962 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -390,7 +390,7 @@ config HPET_TIMER
 
 config HPET_EMULATE_RTC
         def_bool y
-        depends on HPET_TIMER && RTC=y
+        depends on HPET_TIMER && (RTC=y || RTC=m)
 
 # Mark as embedded because too many people got it wrong.
 # The code disables itself when not needed.
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index d65ced59a18f..429d084e014d 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -705,8 +705,6 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
                 rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
                 if (irq_handler)
                         irq_handler(rtc_int_flag, dev_id);
-
-                rtc_interrupt(rtc_int_flag, dev_id);
         }
         return IRQ_HANDLED;
 }