wm831x_power: Only register WM831x battery charger if enabled

Don't tell the system about the battery charger if it's not enabled, we
can reasonably assume that if the charger is not enabled then no battery
will ever be connected so reporting state is at best going to waste time
and at worst going to cause confusing information in the UI.

For simplicity and robustness we continue to register and handle interrupts
from the charger.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
diff --git a/drivers/power/wm831x_power.c b/drivers/power/wm831x_power.c
index 6cc2ca6..c32e6f8 100644
--- a/drivers/power/wm831x_power.c
+++ b/drivers/power/wm831x_power.c
@@ -27,6 +27,7 @@
 	char wall_name[20];
 	char usb_name[20];
 	char battery_name[20];
+	bool have_battery;
 };
 
 static int wm831x_power_check_online(struct wm831x *wm831x, int supply,
@@ -449,7 +450,8 @@
 
 	/* The battery charger is autonomous so we don't need to do
 	 * anything except kick user space */
-	power_supply_changed(&wm831x_power->battery);
+	if (wm831x_power->have_battery)
+		power_supply_changed(&wm831x_power->battery);
 
 	return IRQ_HANDLED;
 }
@@ -479,7 +481,8 @@
 	dev_dbg(wm831x->dev, "Power source changed\n");
 
 	/* Just notify for everything - little harm in overnotifying. */
-	power_supply_changed(&wm831x_power->battery);
+	if (wm831x_power->have_battery)
+		power_supply_changed(&wm831x_power->battery);
 	power_supply_changed(&wm831x_power->usb);
 	power_supply_changed(&wm831x_power->wall);
 
@@ -537,15 +540,6 @@
 	if (ret)
 		goto err_kmalloc;
 
-	battery->name = power->battery_name;
-	battery->properties = wm831x_bat_props;
-	battery->num_properties = ARRAY_SIZE(wm831x_bat_props);
-	battery->get_property = wm831x_bat_get_prop;
-	battery->use_for_apm = 1;
-	ret = power_supply_register(&pdev->dev, battery);
-	if (ret)
-		goto err_wall;
-
 	usb->name = power->usb_name,
 	usb->type = POWER_SUPPLY_TYPE_USB;
 	usb->properties = wm831x_usb_props;
@@ -553,7 +547,23 @@
 	usb->get_property = wm831x_usb_get_prop;
 	ret = power_supply_register(&pdev->dev, usb);
 	if (ret)
-		goto err_battery;
+		goto err_wall;
+
+	ret = wm831x_reg_read(wm831x, WM831X_CHARGER_CONTROL_1);
+	if (ret < 0)
+		goto err_wall;
+	power->have_battery = ret & WM831X_CHG_ENA;
+
+	if (power->have_battery) {
+		    battery->name = power->battery_name;
+		    battery->properties = wm831x_bat_props;
+		    battery->num_properties = ARRAY_SIZE(wm831x_bat_props);
+		    battery->get_property = wm831x_bat_get_prop;
+		    battery->use_for_apm = 1;
+		    ret = power_supply_register(&pdev->dev, battery);
+		    if (ret)
+			    goto err_usb;
+	}
 
 	irq = platform_get_irq_byname(pdev, "SYSLO");
 	ret = request_threaded_irq(irq, NULL, wm831x_syslo_irq,
@@ -562,7 +572,7 @@
 	if (ret != 0) {
 		dev_err(&pdev->dev, "Failed to request SYSLO IRQ %d: %d\n",
 			irq, ret);
-		goto err_usb;
+		goto err_battery;
 	}
 
 	irq = platform_get_irq_byname(pdev, "PWR SRC");
@@ -601,10 +611,11 @@
 err_syslo:
 	irq = platform_get_irq_byname(pdev, "SYSLO");
 	free_irq(irq, power);
+err_battery:
+	if (power->have_battery)
+		power_supply_unregister(battery);
 err_usb:
 	power_supply_unregister(usb);
-err_battery:
-	power_supply_unregister(battery);
 err_wall:
 	power_supply_unregister(wall);
 err_kmalloc:
@@ -628,7 +639,8 @@
 	irq = platform_get_irq_byname(pdev, "SYSLO");
 	free_irq(irq, wm831x_power);
 
-	power_supply_unregister(&wm831x_power->battery);
+	if (wm831x_power->have_battery)
+		power_supply_unregister(&wm831x_power->battery);
 	power_supply_unregister(&wm831x_power->wall);
 	power_supply_unregister(&wm831x_power->usb);
 	kfree(wm831x_power);