power: supply: bq24735-charger: optionally poll the ac-detect gpio

If the ac-detect gpio does not support interrupts, provide a fallback
to poll the gpio at a configurable interval.
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

Documentation/devicetree/bindings/power/supply/ti,bq24735.txt

@@ -27,6 +27,8 @@ Optional properties :
  - ti,external-control : Indicates that the charger is configured externally
    and that the host should not attempt to enable/disable charging or set the
    charge voltage/current.
+ - poll-interval : In case 'interrupts' is not specified, poll AC presence
+   on the ti,ac-detect-gpios GPIO with this interval (milliseconds).
 
 Example:
 

drivers/power/supply/bq24735-charger.c

@@ -50,6 +50,8 @@ struct bq24735 {
 	struct bq24735_platform		*pdata;
 	struct mutex			lock;
 	struct gpio_desc		*status_gpio;
+	struct delayed_work		poll;
+	u32				poll_interval;
 	bool				charging;
 };
 
@@ -209,11 +211,8 @@ static int bq24735_charger_is_charging(struct bq24735 *charger)
 	return !(ret & BQ24735_CHG_OPT_CHARGE_DISABLE);
 }
 
-static irqreturn_t bq24735_charger_isr(int irq, void *devid)
+static void bq24735_update(struct bq24735 *charger)
 {
-	struct power_supply *psy = devid;
-	struct bq24735 *charger = to_bq24735(psy);
-
 	mutex_lock(&charger->lock);
 
 	if (charger->charging && bq24735_charger_is_present(charger))
@@ -223,11 +222,29 @@ static irqreturn_t bq24735_charger_isr(int irq, void *devid)
 
 	mutex_unlock(&charger->lock);
 
-	power_supply_changed(psy);
+	power_supply_changed(charger->charger);
+}
+
+static irqreturn_t bq24735_charger_isr(int irq, void *devid)
+{
+	struct power_supply *psy = devid;
+	struct bq24735 *charger = to_bq24735(psy);
+
+	bq24735_update(charger);
 
 	return IRQ_HANDLED;
 }
 
+static void bq24735_poll(struct work_struct *work)
+{
+	struct bq24735 *charger = container_of(work, struct bq24735, poll.work);
+
+	bq24735_update(charger);
+
+	schedule_delayed_work(&charger->poll,
+			      msecs_to_jiffies(charger->poll_interval));
+}
+
 static int bq24735_charger_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -455,11 +472,32 @@ static int bq24735_charger_probe(struct i2c_client *client,
 				client->irq, ret);
 			return ret;
 		}
+	} else if (charger->status_gpio) {
+		ret = device_property_read_u32(&client->dev, "poll-interval",
+					       &charger->poll_interval);
+		if (ret)
+			return 0;
+		if (!charger->poll_interval)
+			return 0;
+
+		INIT_DELAYED_WORK(&charger->poll, bq24735_poll);
+		schedule_delayed_work(&charger->poll,
+				      msecs_to_jiffies(charger->poll_interval));
 	}
 
 	return 0;
 }
 
+static int bq24735_charger_remove(struct i2c_client *client)
+{
+	struct bq24735 *charger = i2c_get_clientdata(client);
+
+	if (charger->poll_interval)
+		cancel_delayed_work_sync(&charger->poll);
+
+	return 0;
+}
+
 static const struct i2c_device_id bq24735_charger_id[] = {
 	{ "bq24735-charger", 0 },
 	{}
@@ -478,6 +516,7 @@ static struct i2c_driver bq24735_charger_driver = {
 		.of_match_table = bq24735_match_ids,
 	},
 	.probe = bq24735_charger_probe,
+	.remove = bq24735_charger_remove,
 	.id_table = bq24735_charger_id,
 };