[PATCH RFC 05/11] power: supply: max77693: Expose INPUT_CURRENT_LIMIT and CURRENT_MAX

[Artur Weber <aweber.kernel@gmail.com>]

There are two charger current limit registers:

- Fast charge current limit (which controls current going from the
  charger to the battery);
- CHGIN input current limit (which controls current going into the
  charger through the cable, and is managed by the CHARGER regulator).

Add the necessary functions to retrieve the CHGIN input limit (from CHARGER
regulator) and maximum fast charge current values, and expose them as power
supply properties.

Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
---
 drivers/power/supply/max77693_charger.c | 52 +++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/power/supply/max77693_charger.c b/drivers/power/supply/max77693_charger.c
index 2001e12c9f7d..894c35b750b3 100644
--- a/drivers/power/supply/max77693_charger.c
+++ b/drivers/power/supply/max77693_charger.c
@@ -9,6 +9,7 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/mfd/max77693.h>
 #include <linux/mfd/max77693-common.h>
 #include <linux/mfd/max77693-private.h>
@@ -21,6 +22,7 @@ struct max77693_charger {
 	struct device		*dev;
 	struct max77693_dev	*max77693;
 	struct power_supply	*charger;
+	struct regulator	*regu;
 
 	u32 constant_volt;
 	u32 min_system_volt;
@@ -197,12 +199,51 @@ static int max77693_get_online(struct regmap *regmap, int *val)
 	return 0;
 }
 
+/*
+ * There are *two* current limit registers:
+ * - CHGIN limit, which limits the input current from the external charger;
+ * - Fast charge current limit, which limits the current going to the battery.
+ */
+
+static int max77693_get_input_current_limit(struct max77693_charger *chg,
+					    int *val)
+{
+	int ret;
+
+	ret = regulator_get_current_limit(chg->regu);
+	if (ret < 0)
+		return ret;
+
+	*val = ret;
+
+	return 0;
+}
+
+static int max77693_get_fast_charge_current(struct regmap *regmap, int *val)
+{
+	unsigned int data;
+	int ret;
+
+	ret = regmap_read(regmap, MAX77693_CHG_REG_CHG_CNFG_02, &data);
+	if (ret < 0)
+		return ret;
+
+	data &= CHG_CNFG_02_CC_MASK;
+	data >>= CHG_CNFG_02_CC_SHIFT;
+
+	*val = (data * 333 / 10) * 1000; /* 3 steps/0.1A */
+
+	return 0;
+}
+
 static enum power_supply_property max77693_charger_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_CHARGE_TYPE,
 	POWER_SUPPLY_PROP_HEALTH,
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
+	POWER_SUPPLY_PROP_CURRENT_MAX,
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_MANUFACTURER,
 };
@@ -231,6 +272,12 @@ static int max77693_charger_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_ONLINE:
 		ret = max77693_get_online(regmap, &val->intval);
 		break;
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		ret = max77693_get_input_current_limit(chg, &val->intval);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		ret = max77693_get_fast_charge_current(regmap, &val->intval);
+		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME:
 		val->strval = max77693_charger_model;
 		break;
@@ -680,6 +727,11 @@ static int max77693_charger_probe(struct platform_device *pdev)
 	chg->dev = &pdev->dev;
 	chg->max77693 = max77693;
 
+	chg->regu = devm_regulator_get(chg->dev, "CHARGER");
+	if (IS_ERR(chg->regu))
+		return dev_err_probe(&pdev->dev, PTR_ERR(chg->regu),
+				     "failed to get charger regulator\n");
+
 	ret = max77693_dt_init(&pdev->dev, chg);
 	if (ret)
 		return ret;

-- 
2.45.1