sparc: time: Replace update_persistent_clock() with CONFIG_RTC_SYSTOHC

On Sparc systems, update_persistent_clock() uses RTC drivers to do
the job, it makes more sense to hand it over to CONFIG_RTC_SYSTOHC.

In the long run, all the update_persistent_clock() should migrate to
proper class RTC drivers if any and use CONFIG_RTC_SYSTOHC instead.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

arch/sparc/Kconfig

@@ -25,6 +25,7 @@ config SPARC
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select RTC_CLASS
 	select RTC_DRV_M48T59
+	select RTC_SYSTOHC
 	select HAVE_DMA_ATTRS
 	select HAVE_DMA_API_DEBUG
 	select HAVE_ARCH_JUMP_LABEL if SPARC64
@@ -35,7 +36,6 @@ config SPARC
 	select HAVE_BPF_JIT
 	select HAVE_DEBUG_BUGVERBOSE
 	select GENERIC_SMP_IDLE_THREAD
-	select GENERIC_CMOS_UPDATE
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER

arch/sparc/kernel/time_32.c

@@ -23,7 +23,6 @@
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/time.h>
-#include <linux/rtc.h>
 #include <linux/rtc/m48t59.h>
 #include <linux/timex.h>
 #include <linux/clocksource.h>
@@ -65,8 +64,6 @@ DEFINE_PER_CPU(struct clock_event_device, sparc32_clockevent);
 DEFINE_SPINLOCK(rtc_lock);
 EXPORT_SYMBOL(rtc_lock);
 
-static int set_rtc_mmss(unsigned long);
-
 unsigned long profile_pc(struct pt_regs *regs)
 {
 	extern char __copy_user_begin[], __copy_user_end[];
@@ -87,11 +84,6 @@ EXPORT_SYMBOL(profile_pc);
 
 volatile u32 __iomem *master_l10_counter;
 
-int update_persistent_clock(struct timespec now)
-{
-	return set_rtc_mmss(now.tv_sec);
-}
-
 irqreturn_t notrace timer_interrupt(int dummy, void *dev_id)
 {
 	if (timer_cs_enabled) {
@@ -362,16 +354,3 @@ void __init time_init(void)
 		sbus_time_init();
 }
 
-
-static int set_rtc_mmss(unsigned long secs)
-{
-	struct rtc_device *rtc = rtc_class_open("rtc0");
-	int err = -1;
-
-	if (rtc) {
-		err = rtc_set_mmss(rtc, secs);
-		rtc_class_close(rtc);
-	}
-
-	return err;
-}

arch/sparc/kernel/time_64.c

@@ -28,7 +28,6 @@
 #include <linux/cpufreq.h>
 #include <linux/percpu.h>
 #include <linux/miscdevice.h>
-#include <linux/rtc.h>
 #include <linux/rtc/m48t59.h>
 #include <linux/kernel_stat.h>
 #include <linux/clockchips.h>
@@ -394,19 +393,6 @@ static struct sparc64_tick_ops hbtick_operations __read_mostly = {
 
 static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
 
-int update_persistent_clock(struct timespec now)
-{
-	struct rtc_device *rtc = rtc_class_open("rtc0");
-	int err = -1;
-
-	if (rtc) {
-		err = rtc_set_mmss(rtc, now.tv_sec);
-		rtc_class_close(rtc);
-	}
-
-	return err;
-}
-
 unsigned long cmos_regs;
 EXPORT_SYMBOL(cmos_regs);