[PATCH v3] iio: adc: mt6370: Fix ibus and ibat scaling value of some specific vendor ID chips

[ChiaEn Wu <chiaen_wu@richtek.com>]

The scale value of ibus and ibat on the datasheet is incorrect due to the
customer report after the experimentation with some specific vendor ID
chips.

Fixes: c1404d1b659f ("iio: adc: mt6370: Add MediaTek MT6370 support")
Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
---
v3:
- Add 'Fixes' tag
- Revise 'mt6370_adc_get_ibus_scale()' and 'mt6370_adc_get_ibat_scale()'
  from using 'if-else' to using 'switch-case'

v2:
- Move 'get_vendor_info' after iio_priv allocation done
- For the special case, bypass indent, make it out-of-line
- For a simple return, add a blank line
- Drop else
---
---
 drivers/iio/adc/mt6370-adc.c | 53 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/mt6370-adc.c b/drivers/iio/adc/mt6370-adc.c
index bc62e5a..0bc1121 100644
--- a/drivers/iio/adc/mt6370-adc.c
+++ b/drivers/iio/adc/mt6370-adc.c
@@ -19,6 +19,7 @@
 
 #include <dt-bindings/iio/adc/mediatek,mt6370_adc.h>
 
+#define MT6370_REG_DEV_INFO		0x100
 #define MT6370_REG_CHG_CTRL3		0x113
 #define MT6370_REG_CHG_CTRL7		0x117
 #define MT6370_REG_CHG_ADC		0x121
@@ -27,6 +28,7 @@
 #define MT6370_ADC_START_MASK		BIT(0)
 #define MT6370_ADC_IN_SEL_MASK		GENMASK(7, 4)
 #define MT6370_AICR_ICHG_MASK		GENMASK(7, 2)
+#define MT6370_VENID_MASK		GENMASK(7, 4)
 
 #define MT6370_AICR_100_mA		0x0
 #define MT6370_AICR_150_mA		0x1
@@ -47,6 +49,10 @@
 #define ADC_CONV_TIME_MS		35
 #define ADC_CONV_POLLING_TIME_US	1000
 
+#define MT6370_VID_RT5081		0x8
+#define MT6370_VID_RT5081A		0xA
+#define MT6370_VID_MT6370		0xE
+
 struct mt6370_adc_data {
 	struct device *dev;
 	struct regmap *regmap;
@@ -55,6 +61,7 @@ struct mt6370_adc_data {
 	 * from being read at the same time.
 	 */
 	struct mutex adc_lock;
+	unsigned int vid;
 };
 
 static int mt6370_adc_read_channel(struct mt6370_adc_data *priv, int chan,
@@ -98,6 +105,30 @@ static int mt6370_adc_read_channel(struct mt6370_adc_data *priv, int chan,
 	return ret;
 }
 
+static int mt6370_adc_get_ibus_scale(struct mt6370_adc_data *priv)
+{
+	switch (priv->vid) {
+	case MT6370_VID_RT5081:
+	case MT6370_VID_RT5081A:
+	case MT6370_VID_MT6370:
+		return 3350;
+	default:
+		return 3875;
+	}
+}
+
+static int mt6370_adc_get_ibat_scale(struct mt6370_adc_data *priv)
+{
+	switch (priv->vid) {
+	case MT6370_VID_RT5081:
+	case MT6370_VID_RT5081A:
+	case MT6370_VID_MT6370:
+		return 2680;
+	default:
+		return 3870;
+	}
+}
+
 static int mt6370_adc_read_scale(struct mt6370_adc_data *priv,
 				 int chan, int *val1, int *val2)
 {
@@ -123,7 +154,7 @@ static int mt6370_adc_read_scale(struct mt6370_adc_data *priv,
 		case MT6370_AICR_250_mA:
 		case MT6370_AICR_300_mA:
 		case MT6370_AICR_350_mA:
-			*val1 = 3350;
+			*val1 = mt6370_adc_get_ibus_scale(priv);
 			break;
 		default:
 			*val1 = 5000;
@@ -150,7 +181,7 @@ static int mt6370_adc_read_scale(struct mt6370_adc_data *priv,
 		case MT6370_ICHG_600_mA:
 		case MT6370_ICHG_700_mA:
 		case MT6370_ICHG_800_mA:
-			*val1 = 2680;
+			*val1 = mt6370_adc_get_ibat_scale(priv);
 			break;
 		default:
 			*val1 = 5000;
@@ -251,6 +282,20 @@ static const struct iio_chan_spec mt6370_adc_channels[] = {
 	MT6370_ADC_CHAN(TEMP_JC, IIO_TEMP, 12, BIT(IIO_CHAN_INFO_OFFSET)),
 };
 
+static int mt6370_get_vendor_info(struct mt6370_adc_data *priv)
+{
+	unsigned int dev_info;
+	int ret;
+
+	ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info);
+	if (ret)
+		return ret;
+
+	priv->vid = FIELD_GET(MT6370_VENID_MASK, dev_info);
+
+	return 0;
+}
+
 static int mt6370_adc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -272,6 +317,10 @@ static int mt6370_adc_probe(struct platform_device *pdev)
 	priv->regmap = regmap;
 	mutex_init(&priv->adc_lock);
 
+	ret = mt6370_get_vendor_info(priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get vid\n");
+
 	ret = regmap_write(priv->regmap, MT6370_REG_CHG_ADC, 0);
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to reset ADC\n");
-- 
2.7.4