rtc/tpo: Driver to support rtc and wakeup on PowerNV platform

The patch implements the OPAL rtc driver that binds with the rtc
driver subsystem. The driver uses the platform device infrastructure
to probe the rtc device and register it to rtc class framework. The
'wakeup' is supported depending upon the property 'has-tpo' present
in the OF node. It provides a way to load the generic rtc driver in
in the absence of an OPAL driver.

The patch also moves the existing OPAL rtc get/set time interfaces to the
new driver and exposes the necessary OPAL calls using EXPORT_SYMBOL_GPL.

Test results:
-------------
Host:
[root@tul169p1 ~]# ls -l /sys/class/rtc/
total 0
lrwxrwxrwx 1 root root 0 Oct 14 03:07 rtc0 -> ../../devices/opal-rtc/rtc/rtc0
[root@tul169p1 ~]# cat /sys/devices/opal-rtc/rtc/rtc0/time
08:10:07
[root@tul169p1 ~]# echo `date '+%s' -d '+ 2 minutes'` > /sys/class/rtc/rtc0/wakealarm
[root@tul169p1 ~]# cat /sys/class/rtc/rtc0/wakealarm
1413274345
[root@tul169p1 ~]#

FSP:
$ smgr mfgState
standby
$ rtim timeofday

System time is valid: 2014/10/14 08:12:04.225115

$ smgr mfgState
ipling
$

CC: devicetree@vger.kernel.org
CC: tglx@linutronix.de
CC: rtc-linux@googlegroups.com
CC: a.zummo@towertech.it
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 19 insertions, 46 deletions

diff --git a/arch/powerpc/platforms/powernv/opal-rtc.c b/arch/powerpc/platforms/powernv/opal-rtc.c
index 499707ddaa9c..37dbee15769f 100644
--- a/arch/powerpc/platforms/powernv/opal-rtc.c
+++ b/arch/powerpc/platforms/powernv/opal-rtc.c
@@ -15,6 +15,8 @@
 #include <linux/bcd.h>
 #include <linux/rtc.h>
 #include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
 
 #include <asm/opal.h>
 #include <asm/firmware.h>
@@ -43,7 +45,7 @@ unsigned long __init opal_get_boot_time(void)
 	long rc = OPAL_BUSY;
 
 	if (!opal_check_token(OPAL_RTC_READ))
-		goto out;
+		return 0;
 
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
@@ -53,62 +55,33 @@ unsigned long __init opal_get_boot_time(void)
 			mdelay(10);
 	}
 	if (rc != OPAL_SUCCESS)
-		goto out;
+		return 0;
 
 	y_m_d = be32_to_cpu(__y_m_d);
 	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
 	opal_to_tm(y_m_d, h_m_s_ms, &tm);
 	return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 		      tm.tm_hour, tm.tm_min, tm.tm_sec);
-out:
-	ppc_md.get_rtc_time = NULL;
-	ppc_md.set_rtc_time = NULL;
-	return 0;
 }
 
-void opal_get_rtc_time(struct rtc_time *tm)
+static __init int opal_time_init(void)
 {
-	long rc = OPAL_BUSY;
-	u32 y_m_d;
-	u64 h_m_s_ms;
-	__be32 __y_m_d;
-	__be64 __h_m_s_ms;
+	struct platform_device *pdev;
+	struct device_node *rtc;
 
-	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
-		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
-		if (rc == OPAL_BUSY_EVENT)
-			opal_poll_events(NULL);
+	rtc = of_find_node_by_path("/ibm,opal/rtc");
+	if (rtc) {
+		pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
+		of_node_put(rtc);
+	} else {
+		if (opal_check_token(OPAL_RTC_READ) ||
+		    opal_check_token(OPAL_READ_TPO))
+			pdev = platform_device_register_simple("opal-rtc", -1,
+							       NULL, 0);
 		else
-			mdelay(10);
+			return -ENODEV;
 	}
-	if (rc != OPAL_SUCCESS)
-		return;
-	y_m_d = be32_to_cpu(__y_m_d);
-	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
-	opal_to_tm(y_m_d, h_m_s_ms, tm);
-}
-
-int opal_set_rtc_time(struct rtc_time *tm)
-{
-	long rc = OPAL_BUSY;
-	u32 y_m_d = 0;
-	u64 h_m_s_ms = 0;
-
-	y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
-	y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
-	y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
-	y_m_d |= ((u32)bin2bcd(tm->tm_mday));
-
-	h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
-	h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
-	h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
 
-	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
-		rc = opal_rtc_write(y_m_d, h_m_s_ms);
-		if (rc == OPAL_BUSY_EVENT)
-			opal_poll_events(NULL);
-		else
-			mdelay(10);
-	}
-	return rc == OPAL_SUCCESS ? 0 : -EIO;
+	return PTR_ERR_OR_ZERO(pdev);
 }
+machine_subsys_initcall(powernv, opal_time_init);