[POWERPC] Add powerpc get/set_rtc_time interface to new generic rtc class

Add powerpc get/set_rtc_time interface to new generic rtc class. This
abstracts rtc chip specific code from the platform code for rtc-over-i2c
platforms.  Specific RTC chip support is now configured under
Device Drivers -> Real Time Clock. Setting time of day from the RTC
on startup is also configurable.

this time without the potentially platform breaking initcall.
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/time.c

@@ -1048,6 +1048,48 @@ void __init time_init(void)
 	set_dec(tb_ticks_per_jiffy);
 }
 
+#ifdef CONFIG_RTC_CLASS
+static int set_rtc_class_time(struct rtc_time *tm)
+{
+	int err;
+	struct class_device *class_dev =
+		rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
+
+	if (class_dev == NULL)
+		return -ENODEV;
+
+	err = rtc_set_time(class_dev, tm);
+
+	rtc_class_close(class_dev);
+
+	return 0;
+}
+
+static void get_rtc_class_time(struct rtc_time *tm)
+{
+	int err;
+	struct class_device *class_dev =
+		rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
+
+	if (class_dev == NULL)
+		return;
+
+	err = rtc_read_time(class_dev, tm);
+
+	rtc_class_close(class_dev);
+
+	return;
+}
+
+int __init rtc_class_hookup(void)
+{
+	ppc_md.get_rtc_time = get_rtc_class_time;
+	ppc_md.set_rtc_time = set_rtc_class_time;
+
+	return 0;
+}
+#endif /* CONFIG_RTC_CLASS */
+
 
 #define FEBRUARY	2
 #define	STARTOFTIME	1970

include/asm-powerpc/time.h

@@ -39,6 +39,10 @@ extern void generic_calibrate_decr(void);
 extern void wakeup_decrementer(void);
 extern void snapshot_timebase(void);
 
+#ifdef CONFIG_RTC_CLASS
+extern int __init rtc_class_hookup(void);
+#endif
+
 /* Some sane defaults: 125 MHz timebase, 1GHz processor */
 extern unsigned long ppc_proc_freq;
 #define DEFAULT_PROC_FREQ	(DEFAULT_TB_FREQ * 8)
@@ -234,4 +238,4 @@ extern void snapshot_timebases(void);
 #endif
 
 #endif /* __KERNEL__ */
-#endif /* __PPC64_TIME_H */
+#endif /* __POWERPC_TIME_H */