From: Daniel González Cabanelas <dgcbueu@gmail.com>
Subject: [PATCH 2/2] rtc: rs5c372: let the alarm to be used as wakeup source

Currently there is no use for the interrupts on the rs5c372 RTC and the
wakealarm isn't enabled. There are some devices like NASes which use this
RTC to wake up from the power off state when the INTR pin is activated by
the alarm clock.

Enable the alarm and let to be used as a wakeup source.

Tested on a Buffalo LS421DE NAS.

Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
---
 drivers/rtc/rtc-rs5c372.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -833,6 +833,7 @@ static int rs5c372_probe(struct i2c_clie
 	int err = 0;
 	int smbus_mode = 0;
 	struct rs5c372 *rs5c372;
+	bool rs5c372_can_wakeup_device = false;
 
 	dev_dbg(&client->dev, "%s\n", __func__);
 
@@ -868,6 +869,12 @@ static int rs5c372_probe(struct i2c_clie
 	else
 		rs5c372->type = id->driver_data;
 
+#ifdef CONFIG_OF
+	if(of_property_read_bool(client->dev.of_node,
+					      "wakeup-source"))
+		rs5c372_can_wakeup_device = true;
+#endif
+
 	/* we read registers 0x0f then 0x00-0x0f; skip the first one */
 	rs5c372->regs = &rs5c372->buf[1];
 	rs5c372->smbus = smbus_mode;
@@ -901,6 +908,8 @@ static int rs5c372_probe(struct i2c_clie
 		goto exit;
 	}
 
+	rs5c372->has_irq = 1;
+
 	/* if the oscillator lost power and no other software (like
 	 * the bootloader) set it up, do it here.
 	 *
@@ -927,6 +936,10 @@ static int rs5c372_probe(struct i2c_clie
 			);
 
 	/* REVISIT use client->irq to register alarm irq ... */
+	if (rs5c372_can_wakeup_device) {
+		device_init_wakeup(&client->dev, true);
+	}
+
 	rs5c372->rtc = devm_rtc_device_register(&client->dev,
 					rs5c372_driver.driver.name,
 					&rs5c372_rtc_ops, THIS_MODULE);
@@ -940,6 +953,10 @@ static int rs5c372_probe(struct i2c_clie
 	if (err)
 		goto exit;
 
+	/* the rs5c372 alarm only supports a minute accuracy */
+	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rs5c372->rtc->features);
+	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rs5c372->rtc->features);
+
 	return 0;
 
 exit:
