Input: elants_i2c - fix wake-on-touch

When sending "SLEEP" command to the controller it ceases scanning
completely and is unable to wake the system up from sleep, so if it is
configured as a wakeup source we should simply configure interrupt for
wakeup and rely on idle logic within the controller to reduce power
consumption while it is not used.
Signed-off-by: James Chen <james.chen@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/elants_i2c.c

@@ -1316,7 +1316,13 @@ static int __maybe_unused elants_i2c_suspend(struct device *dev)
 
 	disable_irq(client->irq);
 
-	if (device_may_wakeup(dev) || ts->keep_power_in_suspend) {
+	if (device_may_wakeup(dev)) {
+		/*
+		 * The device will automatically enter idle mode
+		 * that has reduced power consumption.
+		 */
+		ts->wake_irq_enabled = (enable_irq_wake(client->irq) == 0);
+	} else if (ts->keep_power_in_suspend) {
 		for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
 			error = elants_i2c_send(client, set_sleep_cmd,
 						sizeof(set_sleep_cmd));
@@ -1326,10 +1332,6 @@ static int __maybe_unused elants_i2c_suspend(struct device *dev)
 			dev_err(&client->dev,
 				"suspend command failed: %d\n", error);
 		}
-
-		if (device_may_wakeup(dev))
-			ts->wake_irq_enabled =
-					(enable_irq_wake(client->irq) == 0);
 	} else {
 		elants_i2c_power_off(ts);
 	}
@@ -1345,10 +1347,11 @@ static int __maybe_unused elants_i2c_resume(struct device *dev)
 	int retry_cnt;
 	int error;
 
-	if (device_may_wakeup(dev) && ts->wake_irq_enabled)
-		disable_irq_wake(client->irq);
-
-	if (ts->keep_power_in_suspend) {
+	if (device_may_wakeup(dev)) {
+		if (ts->wake_irq_enabled)
+			disable_irq_wake(client->irq);
+		elants_i2c_sw_reset(client);
+	} else if (ts->keep_power_in_suspend) {
 		for (retry_cnt = 0; retry_cnt < MAX_RETRIES; retry_cnt++) {
 			error = elants_i2c_send(client, set_active_cmd,
 						sizeof(set_active_cmd));