power: max77843_charger: update to support OTG VBUS control

This patch adds OTG VBUS control function via extcon framwork.
If OTG accessories attached to MUIC(Micro USB Inter), current direction
should change to reverse(Battary -> USB VBUS).

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>

2 files changed, 72 insertions, 1 deletions

diff --git a/drivers/power/max77843_charger.c b/drivers/power/max77843_charger.c
index 392eebc1ae84..3ec08f984620 100644
--- a/drivers/power/max77843_charger.c
+++ b/drivers/power/max77843_charger.c
@@ -9,6 +9,7 @@
  * published bythe Free Software Foundation.
  */
 
+#include <linux/extcon.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
@@ -26,8 +27,12 @@ struct max77843_charger {
 	struct i2c_client	*client;
 	struct regmap		*regmap;
 	struct power_supply	psy;
-
+	struct extcon_dev	*edev;
+	struct work_struct	work;
+	struct notifier_block	otg_nb;
+	struct extcon_specific_cable_nb otg_cable_nb;
 	struct max77843_charger_info	*info;
+	int			extcon_state;
 };
 
 static int max77843_charger_get_max_current(struct max77843_charger *charger)
@@ -438,6 +443,64 @@ static struct max77843_charger_info *max77843_charger_dt_init(
 	return info;
 }
 
+static void max77843_charger_otg_worker(struct work_struct *work)
+{
+	struct max77843_charger *charger =
+		container_of(work, struct max77843_charger, work);
+
+	if (charger->extcon_state) {
+		/* OTG Cable attached */
+		regmap_update_bits(charger->regmap,
+			MAX77843_CHG_REG_CHG_CNFG_00,
+			MAX77843_CHG_MODE_MASK,
+			MAX77843_CHG_OTG_MASK | MAX77843_CHG_BOOST_MASK);
+	} else {
+		/* OTG Cable detached */
+		regmap_update_bits(charger->regmap,
+			MAX77843_CHG_REG_CHG_CNFG_00,
+			MAX77843_CHG_MODE_MASK,
+			MAX77843_CHG_ENABLE | MAX77843_CHG_BUCK_MASK);
+	}
+}
+
+static int max77843_charger_otg_notifier(struct notifier_block *nb,
+		unsigned long event, void *ptr)
+{
+	struct max77843_charger *charger = container_of(nb,
+			struct max77843_charger, otg_nb);
+
+	charger->extcon_state = event;
+	schedule_work(&charger->work);
+
+	return 0;
+}
+
+static int max77843_extcon_register(struct max77843_charger *charger)
+{
+	struct device_node *np = charger->dev->of_node;
+	struct extcon_dev *edev;
+	int ret;
+
+	if (of_property_read_bool(np, "extcon")) {
+		charger->otg_nb.notifier_call = max77843_charger_otg_notifier;
+
+		edev = extcon_get_edev_by_phandle(charger->dev, 0);
+		if (IS_ERR(charger->edev)) {
+			dev_dbg(charger->dev, "Cannot get extcon device\n");
+			return -EPROBE_DEFER;
+		}
+
+		ret = extcon_register_interest(&charger->otg_cable_nb,
+				edev->name, "USB-HOST", &charger->otg_nb);
+		if (ret < 0) {
+			dev_err(charger->dev, "Cannot register OTG notifier\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 static int max77843_charger_probe(struct platform_device *pdev)
 {
 	struct max77843 *max77843 = dev_get_drvdata(pdev->dev.parent);
@@ -453,6 +516,11 @@ static int max77843_charger_probe(struct platform_device *pdev)
 	charger->max77843 = max77843;
 	charger->client = max77843->i2c_chg;
 	charger->regmap = max77843->regmap_chg;
+	INIT_WORK(&charger->work, max77843_charger_otg_worker);
+
+	ret = max77843_extcon_register(charger);
+	if (ret)
+		return ret;
 
 	charger->info = max77843_charger_dt_init(pdev);
 	if (IS_ERR_OR_NULL(charger->info))
diff --git a/include/linux/mfd/max77843-private.h b/include/linux/mfd/max77843-private.h
index 542086c23110..a56e096eb206 100644
--- a/include/linux/mfd/max77843-private.h
+++ b/include/linux/mfd/max77843-private.h
@@ -278,10 +278,13 @@ enum max77843_irq_muic {
 #define MAX77843_CHG_OVER_CURRENT_BAT		(0x06 << 4)
 
 /* MAX77843 CHG_CNFG_00 register */
+#define MAX77843_CHG_MODE_MASK			0x0f
 #define MAX77843_CHG_DISABLE			0x00
 #define MAX77843_CHG_ENABLE			0x05
 #define MAX77843_CHG_MASK			0x01
+#define MAX77843_CHG_OTG_MASK			0x02
 #define MAX77843_CHG_BUCK_MASK			0x04
+#define MAX77843_CHG_BOOST_MASK			0x08
 
 /* MAX77843 CHG_CNFG_01 register */
 #define MAX77843_CHG_RESTART_THRESHOLD_100	0x00