drivers/rtc/rtc-omap.c: add rtc wakeup support to alarm events

On some platforms (like AM33xx), a special register (RTC_IRQWAKEEN) is
available to enable Alarm Wakeup feature.  This register needs to be
properly handled for the rtcwake to work properly.

Platforms using such IP should set "ti,am3352-rtc" in rtc device dt
compatibility node.

Signed-off-by: Hebbar Gururaja <gururaja.hebbar@ti.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 52 insertions, 8 deletions

diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index c6ffbaec32a4..c7d97ee59327 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -70,6 +70,8 @@
 #define OMAP_RTC_KICK0_REG              0x6c
 #define OMAP_RTC_KICK1_REG              0x70
 
+#define OMAP_RTC_IRQWAKEEN              0x7c
+
 /* OMAP_RTC_CTRL_REG bit fields: */
 #define OMAP_RTC_CTRL_SPLIT             (1<<7)
 #define OMAP_RTC_CTRL_DISABLE           (1<<6)
@@ -94,12 +96,21 @@
 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
 
+/* OMAP_RTC_IRQWAKEEN bit fields: */
+#define OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN    (1<<1)
+
 /* OMAP_RTC_KICKER values */
 #define KICK0_VALUE                     0x83e70b13
 #define KICK1_VALUE                     0x95a4f1e0
 
 #define OMAP_RTC_HAS_KICKER             0x1
 
+/*
+ * Few RTC IP revisions has special WAKE-EN Register to enable Wakeup
+ * generation for event Alarm.
+ */
+#define OMAP_RTC_HAS_IRQWAKEEN          0x2
+
 static void __iomem     *rtc_base;
 
 #define rtc_read(addr)          readb(rtc_base + (addr))
@@ -299,12 +310,18 @@ static struct rtc_class_ops omap_rtc_ops = {
 static int omap_rtc_alarm;
 static int omap_rtc_timer;
 
-#define OMAP_RTC_DATA_DA830_IDX 1
+#define OMAP_RTC_DATA_AM3352_IDX        1
+#define OMAP_RTC_DATA_DA830_IDX         2
 
 static struct platform_device_id omap_rtc_devtype[] = {
         {
                 .name   = DRIVER_NAME,
-        }, {
+        },
+        [OMAP_RTC_DATA_AM3352_IDX] = {
+                .name   = "am3352-rtc",
+                .driver_data = OMAP_RTC_HAS_KICKER | OMAP_RTC_HAS_IRQWAKEEN,
+        },
+        [OMAP_RTC_DATA_DA830_IDX] = {
                 .name   = "da830-rtc",
                 .driver_data = OMAP_RTC_HAS_KICKER,
         },
@@ -316,6 +333,9 @@ static const struct of_device_id omap_rtc_of_match[] = {
         {       .compatible     = "ti,da830-rtc",
                 .data           = &omap_rtc_devtype[OMAP_RTC_DATA_DA830_IDX],
         },
+        {       .compatible     = "ti,am3352-rtc",
+                .data           = &omap_rtc_devtype[OMAP_RTC_DATA_AM3352_IDX],
+        },
         {},
 };
 MODULE_DEVICE_TABLE(of, omap_rtc_of_match);
@@ -464,16 +484,28 @@ static u8 irqstat;
 
 static int omap_rtc_suspend(struct device *dev)
 {
+        u8 irqwake_stat;
+        struct platform_device *pdev = to_platform_device(dev);
+        const struct platform_device_id *id_entry =
+                                        platform_get_device_id(pdev);
+
         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 
         /* FIXME the RTC alarm is not currently acting as a wakeup event
-         * source, and in fact this enable() call is just saving a flag
-         * that's never used...
+         * source on some platforms, and in fact this enable() call is just
+         * saving a flag that's never used...
          */
-        if (device_may_wakeup(dev))
+        if (device_may_wakeup(dev)) {
                 enable_irq_wake(omap_rtc_alarm);
-        else
+
+                if (id_entry->driver_data & OMAP_RTC_HAS_IRQWAKEEN) {
+                        irqwake_stat = rtc_read(OMAP_RTC_IRQWAKEEN);
+                        irqwake_stat |= OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
+                        rtc_write(irqwake_stat, OMAP_RTC_IRQWAKEEN);
+                }
+        } else {
                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
+        }
 
         /* Disable the clock/module */
         pm_runtime_put_sync(dev);
@@ -483,13 +515,25 @@ static int omap_rtc_suspend(struct device *dev)
 
 static int omap_rtc_resume(struct device *dev)
 {
+        u8 irqwake_stat;
+        struct platform_device *pdev = to_platform_device(dev);
+        const struct platform_device_id *id_entry =
+                                platform_get_device_id(pdev);
+
         /* Enable the clock/module so that we can access the registers */
         pm_runtime_get_sync(dev);
 
-        if (device_may_wakeup(dev))
+        if (device_may_wakeup(dev)) {
                 disable_irq_wake(omap_rtc_alarm);
-        else
+
+                if (id_entry->driver_data & OMAP_RTC_HAS_IRQWAKEEN) {
+                        irqwake_stat = rtc_read(OMAP_RTC_IRQWAKEEN);
+                        irqwake_stat &= ~OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN;
+                        rtc_write(irqwake_stat, OMAP_RTC_IRQWAKEEN);
+                }
+        } else {
                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
+        }
         return 0;
 }
 #endif