With the recent pinctrl-single changes, SoCs such as Texas
Instrument's OMAP processors can treat wake-up events from deeper idle
states as interrupts.

Let's add support for the optional second interrupt for wake-up
events. And then SoC can wakeup and handle the event using it's
regular handler.

Finally, to pass the wake-up interrupt in the dts file,
interrupts-extended property needs to be passed.

This is similar in approach to commit 2a0b965cfb6e ("serial: omap: Add
support for optional wake-up")

Signed-off-by: Nishanth Menon <n...@ti.com>
---
 drivers/rtc/rtc-ds1307.c |   57 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index f03d5ba..5feedfc 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -15,6 +15,8 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
 #include <linux/string.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
@@ -115,6 +117,7 @@ struct ds1307 {
        struct i2c_client       *client;
        struct rtc_device       *rtc;
        struct work_struct      work;
+       int                     wakeirq;
        s32 (*read_block_data)(const struct i2c_client *client, u8 command,
                               u8 length, u8 *values);
        s32 (*write_block_data)(const struct i2c_client *client, u8 command,
@@ -835,6 +838,34 @@ ds1307_nvram_write(struct file *filp, struct kobject *kobj,
 
 /*----------------------------------------------------------------------*/
 
+static int ds1307_i2c_suspend(struct i2c_client *client,  pm_message_t mesg)
+{
+       struct ds1307 *ds1307 = i2c_get_clientdata(client);
+       struct device *dev = &client->dev;
+
+       if (!ds1307->wakeirq)
+               return 0;
+
+       if (device_may_wakeup(dev))
+               enable_irq(ds1307->wakeirq);
+
+       return 0;
+}
+
+static int ds1307_i2c_resume(struct i2c_client *client)
+{
+       struct ds1307 *ds1307 = i2c_get_clientdata(client);
+       struct device *dev = &client->dev;
+
+       if (!ds1307->wakeirq)
+               return 0;
+
+       if (device_may_wakeup(dev))
+               disable_irq_nosync(ds1307->wakeirq);
+
+       return 0;
+}
+
 static int ds1307_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
 {
@@ -1116,6 +1147,8 @@ read_rtc:
        }
 
        if (want_irq) {
+               struct device_node *node = client->dev.of_node;
+
                err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
                          ds1307->rtc->name, client);
                if (err) {
@@ -1125,6 +1158,28 @@ read_rtc:
 
                        set_bit(HAS_ALARM, &ds1307->flags);
                        dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
+                       if (node)
+                               ds1307->wakeirq = irq_of_parse_and_map(node, 1);
+
+                       if (ds1307->wakeirq <= 0)
+                               ds1307->wakeirq = 0;
+                       else
+                               err = devm_request_irq(&client->dev,
+                                                      ds1307->wakeirq,
+                                                      ds1307_irq,
+                                                      IRQF_ONESHOT,
+                                                      ds1307->rtc->name,
+                                                      client);
+                       if (err) {
+                               dev_err(&client->dev, "unable to get wakeIRQ 
%d\n",
+                                       err);
+                               free_irq(client->irq, client);
+                               goto exit;
+                       }
+
+                       /* We enable the interrupt only during suspend path */
+                       if (ds1307->wakeirq)
+                               disable_irq_nosync(ds1307->wakeirq);
                }
        }
 
@@ -1189,6 +1244,8 @@ static struct i2c_driver ds1307_driver = {
        },
        .probe          = ds1307_probe,
        .remove         = ds1307_remove,
+       .suspend        = ds1307_i2c_suspend,
+       .resume         = ds1307_i2c_resume,
        .id_table       = ds1307_id,
 };
 
-- 
1.7.9.5

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