[PATCH v2 4/7] power: supply: bq24190_charger: add extcon support for USB OTG

[Brian Masney <masneyb@onstation.org>]

Add extcon support so that we can notify USB drivers of cable state
changes. Based on work from Jonathan Marek. USB OTG was tested on a LG
Nexus 5 (hammerhead) phone.

Signed-off-by: Brian Masney <masneyb@onstation.org>
---
 drivers/power/supply/bq24190_charger.c | 37 +++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c
index 9e7f3e33458a..4e64e6ac95c5 100644
--- a/drivers/power/supply/bq24190_charger.c
+++ b/drivers/power/supply/bq24190_charger.c
@@ -21,6 +21,7 @@
 #include <linux/workqueue.h>
 #include <linux/gpio.h>
 #include <linux/i2c.h>
+#include <linux/extcon-provider.h>
 
 #define	BQ24190_MANUFACTURER	"Texas Instruments"
 
@@ -159,6 +160,7 @@
 struct bq24190_dev_info {
 	struct i2c_client		*client;
 	struct device			*dev;
+	struct extcon_dev		*edev;
 	struct power_supply		*charger;
 	struct power_supply		*battery;
 	struct delayed_work		input_current_limit_work;
@@ -174,6 +176,11 @@ struct bq24190_dev_info {
 	u8				watchdog;
 };
 
+static const unsigned int bq24190_usb_extcon_cable[] = {
+	EXTCON_USB,
+	EXTCON_NONE,
+};
+
 /*
  * The tables below provide a 2-way mapping for the value that goes in
  * the register field and the real-world value that it represents.
@@ -1528,6 +1535,20 @@ static const struct power_supply_desc bq24190_battery_desc = {
 	.property_is_writeable	= bq24190_battery_property_is_writeable,
 };
 
+static int bq24190_configure_usb_otg(struct bq24190_dev_info *bdi, u8 ss_reg)
+{
+	bool otg_enabled;
+	int ret;
+
+	otg_enabled = !!(ss_reg & BQ24190_REG_SS_VBUS_STAT_MASK);
+	ret = extcon_set_state_sync(bdi->edev, EXTCON_USB, otg_enabled);
+	if (ret < 0)
+		dev_err(bdi->dev, "Can't set extcon state to %d: %d\n",
+			otg_enabled, ret);
+
+	return ret;
+}
+
 static void bq24190_check_status(struct bq24190_dev_info *bdi)
 {
 	const u8 battery_mask_ss = BQ24190_REG_SS_CHRG_STAT_MASK;
@@ -1597,8 +1618,10 @@ static void bq24190_check_status(struct bq24190_dev_info *bdi)
 		bdi->ss_reg = ss_reg;
 	}
 
-	if (alert_charger || alert_battery)
+	if (alert_charger || alert_battery) {
 		power_supply_changed(bdi->charger);
+		bq24190_configure_usb_otg(bdi, ss_reg);
+	}
 	if (alert_battery && bdi->battery)
 		power_supply_changed(bdi->battery);
 
@@ -1732,6 +1755,14 @@ static int bq24190_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
+	bdi->edev = devm_extcon_dev_allocate(dev, bq24190_usb_extcon_cable);
+	if (IS_ERR(bdi->edev))
+		return PTR_ERR(bdi->edev);
+
+	ret = devm_extcon_dev_register(dev, bdi->edev);
+	if (ret < 0)
+		return ret;
+
 	pm_runtime_enable(dev);
 	pm_runtime_use_autosuspend(dev);
 	pm_runtime_set_autosuspend_delay(dev, 600);
@@ -1778,6 +1809,10 @@ static int bq24190_probe(struct i2c_client *client,
 		goto out_charger;
 	}
 
+	ret = bq24190_configure_usb_otg(bdi, bdi->ss_reg);
+	if (ret < 0)
+		goto out_charger;
+
 	ret = bq24190_sysfs_create_group(bdi);
 	if (ret < 0) {
 		dev_err(dev, "Can't create sysfs entries\n");
-- 
2.17.2