Krzysztof Kozlowski writes:

On Tue, Sep 27, 2016 at 01:31:09AM +0200, Wolfgang Wiedmeyer wrote:

quoted

For MAX77693, the fast charge current also needs to be manipulated for
proper charging. The fast charge current is only set in the case of
the MAX77693 type, as the MAX77843 properly manipulates the fast
charge current.

Are you sure it has to be manipulated? Some time I didn't dig into this.
Now I looked at the datasheet and it says that usually there is no need
for changing the charge current during the operation. Maxim recommends
to setting it to a maximum safe value for the battery. The device will
manage charge current on its own.

However I agree that the charge current should be set... maybe once, to
a maximum value appropriate for battery. Probably this should be done
by max77693_charger in max77693_dt_init().

When charging is disabled (e.g. by removing the USB cable) the charge
current is not reset to zero. So if I expose the current by the
CURRENT_NOW property, it incorrectly reports the current that was set
when charging was enabled, although there is no charging going on
anymore. So I felt the need to update the charge current every time the
charger gets enabled or disabled.
Initially, the charge current is set to zero, so I think it needs to be
set at least at the beginning to enable charging.

Thanks,
Wolfgang

Best regards,
Krzysztof

quoted

The fast charge current is set to the next possible value below the
maximum input current.

quoted

Signed-off-by: Wolfgang Wiedmeyer <redacted>
---
 drivers/regulator/max77693-regulator.c | 45 +++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/max77693-regulator.c b/drivers/regulator/max77693-regulator.c
index cfbb951..e2f7584 100644
--- a/drivers/regulator/max77693-regulator.c
+++ b/drivers/regulator/max77693-regulator.c

@@ -54,14 +54,19 @@ struct chg_reg_data {
 	unsigned int linear_mask;
 	unsigned int uA_step;
 	unsigned int min_sel;
+
+	bool set_fast;
+	unsigned int fast_reg;
+	unsigned int fast_mask;
 };
 
 /*
  * MAX77693 CHARGER regulator - Min : 20mA, Max : 2580mA, step : 20mA
  * 0x00, 0x01, 0x2, 0x03	= 60 mA
  * 0x04 ~ 0x7E			= (60 + (X - 3) * 20) mA
- * Actually for MAX77693 the driver manipulates the maximum input current,
- * not the fast charge current (output). This should be fixed.
+ * Actually for MAX77693 the driver manipulates the maximum input current
+ * and the fast charge current (output) because the fast charge current
+ * is not set.
  *
  * On MAX77843 the calculation formula is the same (except values).
  * Fortunately it properly manipulates the fast charge current.

@@ -100,6 +105,8 @@ static int max77693_chg_set_current_limit(struct regulator_dev *rdev,
 	const struct chg_reg_data *reg_data = rdev_get_drvdata(rdev);
 	unsigned int chg_min_uA = rdev->constraints->min_uA;
 	int sel = 0;
+	unsigned int data;
+	int ret;
 
 	while (chg_min_uA + reg_data->uA_step * sel < min_uA)
 		sel++;

@@ -110,7 +117,35 @@ static int max77693_chg_set_current_limit(struct regulator_dev *rdev,
 	/* the first four codes for charger current are all 60mA */
 	sel += reg_data->min_sel;
 
-	return regmap_write(rdev->regmap, reg_data->linear_reg, sel);
+	ret = regmap_write(rdev->regmap, reg_data->linear_reg, sel);
+	if (ret < 0)
+		return ret;
+
+	if (reg_data->set_fast) {
+		/* disable fast charge if minimum value */
+		if (sel == reg_data->min_sel)
+			data = 0;
+		else {
+			/*
+			 * set the fast charge current to the closest value
+			 * below the input current
+			 */
+			ret = regmap_read(rdev->regmap, reg_data->fast_reg,
+					  &data);
+			if (ret < 0)
+				return ret;
+
+			sel *= reg_data->uA_step / 1000; /* convert to mA */
+			data &= ~reg_data->fast_mask;
+			data |= sel * 10 / 333; /* 0.1A/3 steps */
+		}
+
+		ret = regmap_write(rdev->regmap, reg_data->fast_reg, data);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
 }
 /* end of CHARGER regulator ops */
 

@@ -197,6 +232,9 @@ static const struct chg_reg_data max77693_chg_reg_data = {
 	.linear_mask	= CHG_CNFG_09_CHGIN_ILIM_MASK,
 	.uA_step	= 20000,
 	.min_sel	= 3,
+	.set_fast	= true,
+	.fast_reg	= MAX77693_CHG_REG_CHG_CNFG_02,
+	.fast_mask	= CHG_CNFG_02_CC_MASK,
 };
 
 #define	max77843_regulator_desc_esafeout(num)	{			\

@@ -237,6 +275,7 @@ static const struct chg_reg_data max77843_chg_reg_data = {
 	.linear_mask	= MAX77843_CHG_FAST_CHG_CURRENT_MASK,
 	.uA_step	= MAX77843_CHG_FAST_CHG_CURRENT_STEP,
 	.min_sel	= 2,
+	.set_fast	= false,
 };
 
 static int max77693_pmic_probe(struct platform_device *pdev)

-- 
2.8.0.rc3

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