drivers/rtc/rtc-ds3232.c: enable ds3232 to work as wakeup source

Add suspend/resume and device_init_wakeup to enable ds3232 as wakeup
source, /sys/class/rtc/rtcX/wakealarm for set wakeup alarm.

Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 70 insertions, 24 deletions

diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
index 813c6aa70d3d..adaf06c41479 100644
--- a/drivers/rtc/rtc-ds3232.c
+++ b/drivers/rtc/rtc-ds3232.c
@@ -57,6 +57,7 @@ struct ds3232 {
          * in the remove function.
          */
         struct mutex mutex;
+        bool suspended;
         int exiting;
 };
 
@@ -345,7 +346,15 @@ static irqreturn_t ds3232_irq(int irq, void *dev_id)
         struct ds3232 *ds3232 = i2c_get_clientdata(client);
 
         disable_irq_nosync(irq);
-        schedule_work(&ds3232->work);
+
+        /*
+         * If rtc as a wakeup source, can't schedule the work
+         * at system resume flow, because at this time the i2c bus
+         * has not been resumed.
+         */
+        if (!ds3232->suspended)
+                schedule_work(&ds3232->work);
+
         return IRQ_HANDLED;
 }
 
@@ -363,22 +372,26 @@ static void ds3232_work(struct work_struct *work)
 
         if (stat & DS3232_REG_SR_A1F) {
                 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
-                if (control < 0)
-                        goto out;
-                /* disable alarm1 interrupt */
-                control &= ~(DS3232_REG_CR_A1IE);
-                i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
-
-                /* clear the alarm pend flag */
-                stat &= ~DS3232_REG_SR_A1F;
-                i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
-
-                rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
+                if (control < 0) {
+                        pr_warn("Read DS3232 Control Register error."
+                                "Disable IRQ%d.\n", client->irq);
+                } else {
+                        /* disable alarm1 interrupt */
+                        control &= ~(DS3232_REG_CR_A1IE);
+                        i2c_smbus_write_byte_data(client, DS3232_REG_CR,
+                                                control);
+
+                        /* clear the alarm pend flag */
+                        stat &= ~DS3232_REG_SR_A1F;
+                        i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
+
+                        rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
+
+                        if (!ds3232->exiting)
+                                enable_irq(client->irq);
+                }
         }
 
-out:
-        if (!ds3232->exiting)
-                enable_irq(client->irq);
 unlock:
         mutex_unlock(&ds3232->mutex);
 }
@@ -411,21 +424,17 @@ static int ds3232_probe(struct i2c_client *client,
         if (ret)
                 return ret;
 
-        ds3232->rtc = devm_rtc_device_register(&client->dev, client->name,
-                                          &ds3232_rtc_ops, THIS_MODULE);
-        if (IS_ERR(ds3232->rtc)) {
-                return PTR_ERR(ds3232->rtc);
-        }
-
-        if (client->irq >= 0) {
+        if (client->irq > 0) {
                 ret = devm_request_irq(&client->dev, client->irq, ds3232_irq,
                                        IRQF_SHARED, "ds3232", client);
                 if (ret) {
                         dev_err(&client->dev, "unable to request IRQ\n");
                 }
+                device_init_wakeup(&client->dev, 1);
         }
-
-        return 0;
+        ds3232->rtc = devm_rtc_device_register(&client->dev, client->name,
+                                          &ds3232_rtc_ops, THIS_MODULE);
+        return PTR_ERR_OR_ZERO(ds3232->rtc);
 }
 
 static int ds3232_remove(struct i2c_client *client)
@@ -444,6 +453,42 @@ static int ds3232_remove(struct i2c_client *client)
         return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int ds3232_suspend(struct device *dev)
+{
+        struct ds3232 *ds3232 = dev_get_drvdata(dev);
+        struct i2c_client *client = to_i2c_client(dev);
+
+        if (device_can_wakeup(dev)) {
+                ds3232->suspended = true;
+                irq_set_irq_wake(client->irq, 1);
+        }
+
+        return 0;
+}
+
+static int ds3232_resume(struct device *dev)
+{
+        struct ds3232 *ds3232 = dev_get_drvdata(dev);
+        struct i2c_client *client = to_i2c_client(dev);
+
+        if (ds3232->suspended) {
+                ds3232->suspended = false;
+
+                /* Clear the hardware alarm pend flag */
+                schedule_work(&ds3232->work);
+
+                irq_set_irq_wake(client->irq, 0);
+        }
+
+        return 0;
+}
+#endif
+
+static const struct dev_pm_ops ds3232_pm_ops = {
+        SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume)
+};
+
 static const struct i2c_device_id ds3232_id[] = {
         { "ds3232", 0 },
         { }
@@ -454,6 +499,7 @@ static struct i2c_driver ds3232_driver = {
         .driver = {
                 .name = "rtc-ds3232",
                 .owner = THIS_MODULE,
+                .pm     = &ds3232_pm_ops,
         },
         .probe = ds3232_probe,
         .remove = ds3232_remove,