power: supply: max8997-charger: Improve getting charger status

Detect charging and discharging state. Ported from downstream Samsung
Galaxy S2 (i9100) kernel fork.
Signed-off-by: Timon Baetz <timon.baetz@protonmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/max8997_charger.c

@@ -13,6 +13,20 @@
 #include <linux/mfd/max8997.h>
 #include <linux/mfd/max8997-private.h>
 
+/* MAX8997_REG_STATUS4 */
+#define DCINOK_SHIFT		1
+#define DCINOK_MASK		(1 << DCINOK_SHIFT)
+#define DETBAT_SHIFT		2
+#define DETBAT_MASK		(1 << DETBAT_SHIFT)
+
+/* MAX8997_REG_MBCCTRL1 */
+#define TFCH_SHIFT		4
+#define TFCH_MASK		(7 << TFCH_SHIFT)
+
+/* MAX8997_REG_MBCCTRL5 */
+#define ITOPOFF_SHIFT		0
+#define ITOPOFF_MASK		(0xF << ITOPOFF_SHIFT)
+
 struct charger_data {
 	struct device *dev;
 	struct max8997_dev *iodev;
@@ -20,7 +34,7 @@ struct charger_data {
 };
 
 static enum power_supply_property max8997_battery_props[] = {
-	POWER_SUPPLY_PROP_STATUS, /* "FULL" or "NOT FULL" only. */
+	POWER_SUPPLY_PROP_STATUS, /* "FULL", "CHARGING" or "DISCHARGING". */
 	POWER_SUPPLY_PROP_PRESENT, /* the presence of battery */
 	POWER_SUPPLY_PROP_ONLINE, /* charger is active or not */
 };
@@ -43,6 +57,10 @@ static int max8997_battery_get_property(struct power_supply *psy,
 			return ret;
 		if ((reg & (1 << 0)) == 0x1)
 			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else if ((reg & DCINOK_MASK))
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		else
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 
 		break;
 	case POWER_SUPPLY_PROP_PRESENT:
@@ -50,7 +68,7 @@ static int max8997_battery_get_property(struct power_supply *psy,
 		ret = max8997_read_reg(i2c, MAX8997_REG_STATUS4, &reg);
 		if (ret)
 			return ret;
-		if ((reg & (1 << 2)) == 0x0)
+		if ((reg & DETBAT_MASK) == 0x0)
 			val->intval = 1;
 
 		break;
@@ -59,8 +77,7 @@ static int max8997_battery_get_property(struct power_supply *psy,
 		ret = max8997_read_reg(i2c, MAX8997_REG_STATUS4, &reg);
 		if (ret)
 			return ret;
-		/* DCINOK */
-		if (reg & (1 << 1))
+		if (reg & DCINOK_MASK)
 			val->intval = 1;
 
 		break;
@@ -84,11 +101,14 @@ static int max8997_battery_probe(struct platform_device *pdev)
 	int ret = 0;
 	struct charger_data *charger;
 	struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+	struct i2c_client *i2c = iodev->i2c;
 	struct max8997_platform_data *pdata = iodev->pdata;
 	struct power_supply_config psy_cfg = {};
 
-	if (!pdata)
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data supplied.\n");
 		return -EINVAL;
+	}
 
 	if (pdata->eoc_mA) {
 		int val = (pdata->eoc_mA - 50) / 10;
@@ -97,30 +117,29 @@ static int max8997_battery_probe(struct platform_device *pdev)
 		if (val > 0xf)
 			val = 0xf;
 
-		ret = max8997_update_reg(iodev->i2c,
-				MAX8997_REG_MBCCTRL5, val, 0xf);
+		ret = max8997_update_reg(i2c, MAX8997_REG_MBCCTRL5,
+				val << ITOPOFF_SHIFT, ITOPOFF_MASK);
 		if (ret < 0) {
 			dev_err(&pdev->dev, "Cannot use i2c bus.\n");
 			return ret;
 		}
 	}
-
 	switch (pdata->timeout) {
 	case 5:
-		ret = max8997_update_reg(iodev->i2c, MAX8997_REG_MBCCTRL1,
-				0x2 << 4, 0x7 << 4);
+		ret = max8997_update_reg(i2c, MAX8997_REG_MBCCTRL1,
+				0x2 << TFCH_SHIFT, TFCH_MASK);
 		break;
 	case 6:
-		ret = max8997_update_reg(iodev->i2c, MAX8997_REG_MBCCTRL1,
-				0x3 << 4, 0x7 << 4);
+		ret = max8997_update_reg(i2c, MAX8997_REG_MBCCTRL1,
+				0x3 << TFCH_SHIFT, TFCH_MASK);
 		break;
 	case 7:
-		ret = max8997_update_reg(iodev->i2c, MAX8997_REG_MBCCTRL1,
-				0x4 << 4, 0x7 << 4);
+		ret = max8997_update_reg(i2c, MAX8997_REG_MBCCTRL1,
+				0x4 << TFCH_SHIFT, TFCH_MASK);
 		break;
 	case 0:
-		ret = max8997_update_reg(iodev->i2c, MAX8997_REG_MBCCTRL1,
-				0x7 << 4, 0x7 << 4);
+		ret = max8997_update_reg(i2c, MAX8997_REG_MBCCTRL1,
+				0x7 << TFCH_SHIFT, TFCH_MASK);
 		break;
 	default:
 		dev_err(&pdev->dev, "incorrect timeout value (%d)\n",
@@ -138,7 +157,6 @@ static int max8997_battery_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, charger);
 
-
 	charger->dev = &pdev->dev;
 	charger->iodev = iodev;