hwmon: (lm90) Add support to handle IRQ

When the temperature exceed the limit range value,
the driver can handle the interrupt.
Signed-off-by: NWei Ni <wni@nvidia.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/hwmon/lm90.c

@@ -89,6 +89,7 @@
 #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/sysfs.h>
+#include <linux/interrupt.h>
 
 /*
  * Addresses to scan
@@ -1445,6 +1446,17 @@ static bool lm90_is_tripped(struct i2c_client *client, u16 *status)
 	return true;
 }
 
+static irqreturn_t lm90_irq_thread(int irq, void *dev_id)
+{
+	struct i2c_client *client = dev_id;
+	u16 status;
+
+	if (lm90_is_tripped(client, &status))
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
+}
+
 static int lm90_probe(struct i2c_client *client,
 		      const struct i2c_device_id *id)
 {
@@ -1521,6 +1533,18 @@ static int lm90_probe(struct i2c_client *client,
 		goto exit_remove_files;
 	}
 
+	if (client->irq) {
+		dev_dbg(dev, "IRQ: %d\n", client->irq);
+		err = devm_request_threaded_irq(dev, client->irq,
+						NULL, lm90_irq_thread,
+						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						"lm90", client);
+		if (err < 0) {
+			dev_err(dev, "cannot request IRQ %d\n", client->irq);
+			goto exit_remove_files;
+		}
+	}
+
 	return 0;
 
 exit_remove_files: